Add Stream wrappers for memory and text-based types

[ViveliDuCh]

Fixes#82801

Introduces standardized stream wrappers for text and memory types as public sealed classes (StringStream, ReadOnlyMemoryStream, WritableMemoryStream, and ReadOnlySequenceStream ) as approved in API review (video).

What's included

• StringStream (System.IO, CoreLib): non-seekable, read-only stream that encodes string or ReadOnlyMemory<char> on-the-fly. Encoding is required (no default). Never emits BOMs.
• ReadOnlyMemoryStream (System.IO, CoreLib): seekable, read-only stream over ReadOnlyMemory<byte>
• WritableMemoryStream (System.IO, CoreLib): seekable, read-write stream over Memory<byte> with fixed capacity
• ReadOnlySequenceStream (System.Buffers, System.Memory): seekable, read-only stream over ReadOnlySequence<byte>
• Ref assembly updates for System.Runtime and System.Memory
• Updated 3 internal call sites (ReadOnlyMemoryContent, XmlPreloadedResolver, JsonXmlDataContract) to use the new types
• Conformance and behavioral tests for all 4 types

Implementation notes

• All types are public sealed with direct constructors: the review moved away from factory methods on Stream to avoid derived-type IntelliSense noise
• StringStream encodes directly into the caller's buffer in Read() rather than using an internal byte buffer
• ReadOnlyMemoryStream and WritableMemoryStream derive from MemoryStream.
• TryGetBuffer returns false and GetBuffer throws on the memory stream types (no publiclyVisible support for now)

Limitations

• The internal shared-sourceReadOnlyMemoryStream in Common/ cannot be fully replaced:
  • System.Memory.Data multi-targets netstandard2.0 where the new public type doesn't exist.
  • System.Net.Http (net11.0 only) can adopt it directly.

Follow-up work

• IBufferWriter<byte> → Stream wrapper (separate proposal per #100434)

[Copilot]

Pull request overview

This PR introduces new standardized Stream wrapper types across CoreLib and System.Memory, aligning with the approved API shape from #82801 and updating a few internal call sites to use the new wrappers.

Changes:

• Added new public sealed stream wrappers: StringStream, ReadOnlyMemoryStream, WritableMemoryStream (CoreLib) and ReadOnlySequenceStream (System.Memory).
• Updated reference assemblies and project files to expose/compile the new APIs.
• Added conformance + targeted behavioral tests, and updated select internal consumers to use StringStream.

Reviewed changes

Copilot reviewed 23 out of 23 changed files in this pull request and generated 9 comments.

Show a summary per file

File	Description
src/libraries/System.Private.CoreLib/src/System/IO/StringStream.cs	Implements the new StringStream API (read-only, non-seekable, on-the-fly encoding).
src/libraries/System.Private.CoreLib/src/System/IO/ReadOnlyMemoryStream.cs	Implements seekable read-only stream over ReadOnlyMemory<byte>.
src/libraries/System.Private.CoreLib/src/System/IO/WritableMemoryStream.cs	Implements seekable fixed-capacity read/write stream over Memory<byte>.
src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitems	Wires new CoreLib stream wrapper source files into the build.
src/libraries/System.Private.CoreLib/src/Resources/Strings.resx	Adds a new resource string entry (currently appears unused).
src/libraries/System.Runtime/ref/System.Runtime.cs	Updates public API surface to include the new stream wrapper types (and a small ref signature normalization change).
src/libraries/System.Runtime/tests/System.IO.Tests/System.IO.Tests.csproj	Includes the new test files in the System.IO test project.
src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamConformanceTests.cs	Adds conformance coverage for StringStream (string + ReadOnlyMemory<char> overloads).
src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_String.cs	Adds targeted StringStream(string, Encoding) behavioral tests.
src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_Memory.cs	Adds targeted StringStream(ReadOnlyMemory<char>, Encoding) behavioral tests.
src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamConformanceTests.cs	Adds conformance coverage for ReadOnlyMemoryStream.
src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamTests.cs	Adds targeted ReadOnlyMemoryStream behavioral tests.
src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamConformanceTests.cs	Adds conformance coverage for WritableMemoryStream (with some overridden tests).
src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamTests.cs	Adds targeted WritableMemoryStream behavioral tests.
src/libraries/System.Memory/src/System/Buffers/ReadOnlySequenceStream.cs	Implements ReadOnlySequenceStream over ReadOnlySequence<byte>.
src/libraries/System.Memory/src/System.Memory.csproj	Includes the new ReadOnlySequenceStream source file in System.Memory.
src/libraries/System.Memory/src/Resources/Strings.resx	Adds SR strings needed for stream-like exception messages in System.Memory.
src/libraries/System.Memory/ref/System.Memory.cs	Adds ReadOnlySequenceStream to the System.Memory ref surface.
src/libraries/System.Memory/tests/System.Memory.Tests.csproj	Adds tests for ReadOnlySequenceStream and references StreamConformanceTests.
src/libraries/System.Memory/tests/ReadOnlyBuffer/ReadOnlySequenceStreamTests.cs	Adds targeted behavioral tests for multi-segment ReadOnlySequenceStream scenarios.
src/libraries/System.Memory/tests/ReadOnlyBuffer/ReadOnlySequenceStream.ConformanceTests.cs	Adds conformance coverage for ReadOnlySequenceStream.
src/libraries/System.Private.Xml/src/System/Xml/Resolvers/XmlPreloadedResolver.cs	Switches internal string-to-stream conversion to StringStream.
src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.cs	Switches internal string-to-stream conversion to StringStream.

Comments suppressed due to low confidence (1)

src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.cs:38

• Variable is still named 'memoryStream' but the implementation is now StringStream (not a MemoryStream). Rename the local to avoid implying the stream is seekable/in-memory-buffered (e.g., 'xmlContentStream').

 Stream memoryStream = new StringStream(xmlContent, Encoding.UTF8);
object? xmlValue;
XmlDictionaryReaderQuotas? quotas = ((JsonReaderDelegator)jsonReader).ReaderQuotas;
if (quotas == null)
{
xmlValue = dataContractSerializer.ReadObject(memoryStream);

[Copilot]

Pull request overview

Copilot reviewed 23 out of 23 changed files in this pull request and generated 10 comments.

[Copilot]

Pull request overview

Copilot reviewed 23 out of 23 changed files in this pull request and generated 3 comments.

[Copilot]

Pull request overview

Copilot reviewed 28 out of 29 changed files in this pull request and generated 1 comment.

[SimonCropp]

awesome. that .net preview will this be in?

[jozkee]

/backport to release/11.0-preview6

[github-actions]

Started backporting to release/11.0-preview6 (link to workflow run)

[github-actions]

@jozkee backporting to release/11.0-preview6 failed, the patch most likely resulted in conflicts. Please backport manually!

git am output

$ git am --3way --empty=keep --ignore-whitespace --keep-non-patch changes.patchApplying: First API proposal implementationUsing index info to reconstruct a base tree...M	src/libraries/System.Memory/ref/System.Memory.csM	src/libraries/System.Memory/tests/System.Memory.Tests.csprojM	src/libraries/System.Private.CoreLib/src/Resources/Strings.resxM	src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitemsM	src/libraries/System.Runtime/ref/System.Runtime.csFalling back to patching base and 3-way merge...Auto-merging src/libraries/System.Memory/ref/System.Memory.csAuto-merging src/libraries/System.Memory/tests/System.Memory.Tests.csprojAuto-merging src/libraries/System.Private.CoreLib/src/Resources/Strings.resxAuto-merging src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitemsAuto-merging src/libraries/System.Runtime/ref/System.Runtime.csApplying: API replacements in production codeApplying: Implementation update based on latest API Review final consensusApplying: Address PR feedback. MemoryStream base change. Spillover buffer for Convert edge case. Flush strategy update.Applying: Address PR feedbackApplying: Address PR feedback: fix StringStream flush offset, WritableMemoryStream length/seek semantics, ReadOnlySequenceStream safety, and consolidate testsApplying: Address PR feedback: remove redundant code, improve test coverage and structureUsing index info to reconstruct a base tree...M	src/libraries/System.Memory/src/System/Buffers/ReadOnlySequenceStream.csM	src/libraries/System.Net.Http/src/System.Net.Http.csprojM	src/libraries/System.Private.CoreLib/src/System/IO/WritableMemoryStream.csM	src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.csM	src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamConformanceTests.csM	src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_Memory.csM	src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_String.csM	src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamConformanceTests.csM	src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamTests.csFalling back to patching base and 3-way merge...Auto-merging src/libraries/System.Memory/src/System/Buffers/ReadOnlySequenceStream.csAuto-merging src/libraries/System.Net.Http/src/System.Net.Http.csprojAuto-merging src/libraries/System.Private.CoreLib/src/System/IO/WritableMemoryStream.csAuto-merging src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.csCONFLICT (content): Merge conflict in src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamConformanceTests.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamConformanceTests.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_Memory.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_Memory.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_String.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_String.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamConformanceTests.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamConformanceTests.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamTests.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamTests.cserror: Failed to merge in the changes.hint: Use 'git am --show-current-patch=diff' to see the failed patchhint: When you have resolved this problem, run "git am --continue".hint: If you prefer to skip this patch, run "git am --skip" instead.hint: To restore the original branch and stop patching, run "git am --abort".hint: Disable this message with "git config set advice.mergeConflict false"Patch failed at 0007 Address PR feedback: remove redundant code, improve test coverage and structureError: The process '/usr/bin/git' failed with exit code 128

Link to workflow output

[ViveliDuCh]

Fixes#82801

Introduces standardized stream wrappers for text and memory types as public sealed classes (StringStream, ReadOnlyMemoryStream, WritableMemoryStream, and ReadOnlySequenceStream ) as approved in API review (video).

What's included

• StringStream (System.IO, CoreLib): non-seekable, read-only stream that encodes string or ReadOnlyMemory<char> on-the-fly. Encoding is required (no default). Never emits BOMs.
• ReadOnlyMemoryStream (System.IO, CoreLib): seekable, read-only stream over ReadOnlyMemory<byte>
• WritableMemoryStream (System.IO, CoreLib): seekable, read-write stream over Memory<byte> with fixed capacity
• ReadOnlySequenceStream (System.Buffers, System.Memory): seekable, read-only stream over ReadOnlySequence<byte>
• Ref assembly updates for System.Runtime and System.Memory
• Updated 3 internal call sites (ReadOnlyMemoryContent, XmlPreloadedResolver, JsonXmlDataContract) to use the new types
• Conformance and behavioral tests for all 4 types

Implementation notes

• All types are public sealed with direct constructors: the review moved away from factory methods on Stream to avoid derived-type IntelliSense noise
• StringStream encodes directly into the caller's buffer in Read() rather than using an internal byte buffer
• ReadOnlyMemoryStream and WritableMemoryStream derive from MemoryStream.
• TryGetBuffer returns false and GetBuffer throws on the memory stream types (no publiclyVisible support for now)

Limitations

• The internal shared-sourceReadOnlyMemoryStream in Common/ cannot be fully replaced:
  • System.Memory.Data multi-targets netstandard2.0 where the new public type doesn't exist.
  • System.Net.Http (net11.0 only) can adopt it directly.

Follow-up work

• IBufferWriter<byte> → Stream wrapper (separate proposal per #100434)

[Copilot]

Pull request overview

This PR introduces new standardized Stream wrapper types across CoreLib and System.Memory, aligning with the approved API shape from #82801 and updating a few internal call sites to use the new wrappers.

Changes:

• Added new public sealed stream wrappers: StringStream, ReadOnlyMemoryStream, WritableMemoryStream (CoreLib) and ReadOnlySequenceStream (System.Memory).
• Updated reference assemblies and project files to expose/compile the new APIs.
• Added conformance + targeted behavioral tests, and updated select internal consumers to use StringStream.

Reviewed changes

Copilot reviewed 23 out of 23 changed files in this pull request and generated 9 comments.

Show a summary per file

File	Description
src/libraries/System.Private.CoreLib/src/System/IO/StringStream.cs	Implements the new StringStream API (read-only, non-seekable, on-the-fly encoding).
src/libraries/System.Private.CoreLib/src/System/IO/ReadOnlyMemoryStream.cs	Implements seekable read-only stream over ReadOnlyMemory<byte>.
src/libraries/System.Private.CoreLib/src/System/IO/WritableMemoryStream.cs	Implements seekable fixed-capacity read/write stream over Memory<byte>.
src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitems	Wires new CoreLib stream wrapper source files into the build.
src/libraries/System.Private.CoreLib/src/Resources/Strings.resx	Adds a new resource string entry (currently appears unused).
src/libraries/System.Runtime/ref/System.Runtime.cs	Updates public API surface to include the new stream wrapper types (and a small ref signature normalization change).
src/libraries/System.Runtime/tests/System.IO.Tests/System.IO.Tests.csproj	Includes the new test files in the System.IO test project.
src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamConformanceTests.cs	Adds conformance coverage for StringStream (string + ReadOnlyMemory<char> overloads).
src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_String.cs	Adds targeted StringStream(string, Encoding) behavioral tests.
src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_Memory.cs	Adds targeted StringStream(ReadOnlyMemory<char>, Encoding) behavioral tests.
src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamConformanceTests.cs	Adds conformance coverage for ReadOnlyMemoryStream.
src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamTests.cs	Adds targeted ReadOnlyMemoryStream behavioral tests.
src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamConformanceTests.cs	Adds conformance coverage for WritableMemoryStream (with some overridden tests).
src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamTests.cs	Adds targeted WritableMemoryStream behavioral tests.
src/libraries/System.Memory/src/System/Buffers/ReadOnlySequenceStream.cs	Implements ReadOnlySequenceStream over ReadOnlySequence<byte>.
src/libraries/System.Memory/src/System.Memory.csproj	Includes the new ReadOnlySequenceStream source file in System.Memory.
src/libraries/System.Memory/src/Resources/Strings.resx	Adds SR strings needed for stream-like exception messages in System.Memory.
src/libraries/System.Memory/ref/System.Memory.cs	Adds ReadOnlySequenceStream to the System.Memory ref surface.
src/libraries/System.Memory/tests/System.Memory.Tests.csproj	Adds tests for ReadOnlySequenceStream and references StreamConformanceTests.
src/libraries/System.Memory/tests/ReadOnlyBuffer/ReadOnlySequenceStreamTests.cs	Adds targeted behavioral tests for multi-segment ReadOnlySequenceStream scenarios.
src/libraries/System.Memory/tests/ReadOnlyBuffer/ReadOnlySequenceStream.ConformanceTests.cs	Adds conformance coverage for ReadOnlySequenceStream.
src/libraries/System.Private.Xml/src/System/Xml/Resolvers/XmlPreloadedResolver.cs	Switches internal string-to-stream conversion to StringStream.
src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.cs	Switches internal string-to-stream conversion to StringStream.

Comments suppressed due to low confidence (1)

src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.cs:38

• Variable is still named 'memoryStream' but the implementation is now StringStream (not a MemoryStream). Rename the local to avoid implying the stream is seekable/in-memory-buffered (e.g., 'xmlContentStream').

 Stream memoryStream = new StringStream(xmlContent, Encoding.UTF8);
object? xmlValue;
XmlDictionaryReaderQuotas? quotas = ((JsonReaderDelegator)jsonReader).ReaderQuotas;
if (quotas == null)
{
xmlValue = dataContractSerializer.ReadObject(memoryStream);

[Copilot]

Pull request overview

Copilot reviewed 23 out of 23 changed files in this pull request and generated 10 comments.

[Copilot]

Pull request overview

Copilot reviewed 23 out of 23 changed files in this pull request and generated 3 comments.

[Copilot]

Pull request overview

Copilot reviewed 28 out of 29 changed files in this pull request and generated 1 comment.

[SimonCropp]

awesome. that .net preview will this be in?

[jozkee]

/backport to release/11.0-preview6

[github-actions]

Started backporting to release/11.0-preview6 (link to workflow run)

[github-actions]

@jozkee backporting to release/11.0-preview6 failed, the patch most likely resulted in conflicts. Please backport manually!

git am output

$ git am --3way --empty=keep --ignore-whitespace --keep-non-patch changes.patchApplying: First API proposal implementationUsing index info to reconstruct a base tree...M	src/libraries/System.Memory/ref/System.Memory.csM	src/libraries/System.Memory/tests/System.Memory.Tests.csprojM	src/libraries/System.Private.CoreLib/src/Resources/Strings.resxM	src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitemsM	src/libraries/System.Runtime/ref/System.Runtime.csFalling back to patching base and 3-way merge...Auto-merging src/libraries/System.Memory/ref/System.Memory.csAuto-merging src/libraries/System.Memory/tests/System.Memory.Tests.csprojAuto-merging src/libraries/System.Private.CoreLib/src/Resources/Strings.resxAuto-merging src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitemsAuto-merging src/libraries/System.Runtime/ref/System.Runtime.csApplying: API replacements in production codeApplying: Implementation update based on latest API Review final consensusApplying: Address PR feedback. MemoryStream base change. Spillover buffer for Convert edge case. Flush strategy update.Applying: Address PR feedbackApplying: Address PR feedback: fix StringStream flush offset, WritableMemoryStream length/seek semantics, ReadOnlySequenceStream safety, and consolidate testsApplying: Address PR feedback: remove redundant code, improve test coverage and structureUsing index info to reconstruct a base tree...M	src/libraries/System.Memory/src/System/Buffers/ReadOnlySequenceStream.csM	src/libraries/System.Net.Http/src/System.Net.Http.csprojM	src/libraries/System.Private.CoreLib/src/System/IO/WritableMemoryStream.csM	src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.csM	src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamConformanceTests.csM	src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_Memory.csM	src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_String.csM	src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamConformanceTests.csM	src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamTests.csFalling back to patching base and 3-way merge...Auto-merging src/libraries/System.Memory/src/System/Buffers/ReadOnlySequenceStream.csAuto-merging src/libraries/System.Net.Http/src/System.Net.Http.csprojAuto-merging src/libraries/System.Private.CoreLib/src/System/IO/WritableMemoryStream.csAuto-merging src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.csCONFLICT (content): Merge conflict in src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamConformanceTests.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamConformanceTests.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_Memory.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_Memory.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_String.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_String.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamConformanceTests.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamConformanceTests.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamTests.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamTests.cserror: Failed to merge in the changes.hint: Use 'git am --show-current-patch=diff' to see the failed patchhint: When you have resolved this problem, run "git am --continue".hint: If you prefer to skip this patch, run "git am --skip" instead.hint: To restore the original branch and stop patching, run "git am --abort".hint: Disable this message with "git config set advice.mergeConflict false"Patch failed at 0007 Address PR feedback: remove redundant code, improve test coverage and structureError: The process '/usr/bin/git' failed with exit code 128

Link to workflow output

[ViveliDuCh]

Fixes#82801

Introduces standardized stream wrappers for text and memory types as public sealed classes (StringStream, ReadOnlyMemoryStream, WritableMemoryStream, and ReadOnlySequenceStream ) as approved in API review (video).

What's included

• StringStream (System.IO, CoreLib): non-seekable, read-only stream that encodes string or ReadOnlyMemory<char> on-the-fly. Encoding is required (no default). Never emits BOMs.
• ReadOnlyMemoryStream (System.IO, CoreLib): seekable, read-only stream over ReadOnlyMemory<byte>
• WritableMemoryStream (System.IO, CoreLib): seekable, read-write stream over Memory<byte> with fixed capacity
• ReadOnlySequenceStream (System.Buffers, System.Memory): seekable, read-only stream over ReadOnlySequence<byte>
• Ref assembly updates for System.Runtime and System.Memory
• Updated 3 internal call sites (ReadOnlyMemoryContent, XmlPreloadedResolver, JsonXmlDataContract) to use the new types
• Conformance and behavioral tests for all 4 types

Implementation notes

• All types are public sealed with direct constructors: the review moved away from factory methods on Stream to avoid derived-type IntelliSense noise
• StringStream encodes directly into the caller's buffer in Read() rather than using an internal byte buffer
• ReadOnlyMemoryStream and WritableMemoryStream derive from MemoryStream.
• TryGetBuffer returns false and GetBuffer throws on the memory stream types (no publiclyVisible support for now)

Limitations

• The internal shared-sourceReadOnlyMemoryStream in Common/ cannot be fully replaced:
  • System.Memory.Data multi-targets netstandard2.0 where the new public type doesn't exist.
  • System.Net.Http (net11.0 only) can adopt it directly.

Follow-up work

• IBufferWriter<byte> → Stream wrapper (separate proposal per #100434)

[Copilot]

Pull request overview

This PR introduces new standardized Stream wrapper types across CoreLib and System.Memory, aligning with the approved API shape from #82801 and updating a few internal call sites to use the new wrappers.

Changes:

• Added new public sealed stream wrappers: StringStream, ReadOnlyMemoryStream, WritableMemoryStream (CoreLib) and ReadOnlySequenceStream (System.Memory).
• Updated reference assemblies and project files to expose/compile the new APIs.
• Added conformance + targeted behavioral tests, and updated select internal consumers to use StringStream.

Reviewed changes

Copilot reviewed 23 out of 23 changed files in this pull request and generated 9 comments.

Show a summary per file

File	Description
src/libraries/System.Private.CoreLib/src/System/IO/StringStream.cs	Implements the new StringStream API (read-only, non-seekable, on-the-fly encoding).
src/libraries/System.Private.CoreLib/src/System/IO/ReadOnlyMemoryStream.cs	Implements seekable read-only stream over ReadOnlyMemory<byte>.
src/libraries/System.Private.CoreLib/src/System/IO/WritableMemoryStream.cs	Implements seekable fixed-capacity read/write stream over Memory<byte>.
src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitems	Wires new CoreLib stream wrapper source files into the build.
src/libraries/System.Private.CoreLib/src/Resources/Strings.resx	Adds a new resource string entry (currently appears unused).
src/libraries/System.Runtime/ref/System.Runtime.cs	Updates public API surface to include the new stream wrapper types (and a small ref signature normalization change).
src/libraries/System.Runtime/tests/System.IO.Tests/System.IO.Tests.csproj	Includes the new test files in the System.IO test project.
src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamConformanceTests.cs	Adds conformance coverage for StringStream (string + ReadOnlyMemory<char> overloads).
src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_String.cs	Adds targeted StringStream(string, Encoding) behavioral tests.
src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_Memory.cs	Adds targeted StringStream(ReadOnlyMemory<char>, Encoding) behavioral tests.
src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamConformanceTests.cs	Adds conformance coverage for ReadOnlyMemoryStream.
src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamTests.cs	Adds targeted ReadOnlyMemoryStream behavioral tests.
src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamConformanceTests.cs	Adds conformance coverage for WritableMemoryStream (with some overridden tests).
src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamTests.cs	Adds targeted WritableMemoryStream behavioral tests.
src/libraries/System.Memory/src/System/Buffers/ReadOnlySequenceStream.cs	Implements ReadOnlySequenceStream over ReadOnlySequence<byte>.
src/libraries/System.Memory/src/System.Memory.csproj	Includes the new ReadOnlySequenceStream source file in System.Memory.
src/libraries/System.Memory/src/Resources/Strings.resx	Adds SR strings needed for stream-like exception messages in System.Memory.
src/libraries/System.Memory/ref/System.Memory.cs	Adds ReadOnlySequenceStream to the System.Memory ref surface.
src/libraries/System.Memory/tests/System.Memory.Tests.csproj	Adds tests for ReadOnlySequenceStream and references StreamConformanceTests.
src/libraries/System.Memory/tests/ReadOnlyBuffer/ReadOnlySequenceStreamTests.cs	Adds targeted behavioral tests for multi-segment ReadOnlySequenceStream scenarios.
src/libraries/System.Memory/tests/ReadOnlyBuffer/ReadOnlySequenceStream.ConformanceTests.cs	Adds conformance coverage for ReadOnlySequenceStream.
src/libraries/System.Private.Xml/src/System/Xml/Resolvers/XmlPreloadedResolver.cs	Switches internal string-to-stream conversion to StringStream.
src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.cs	Switches internal string-to-stream conversion to StringStream.

Comments suppressed due to low confidence (1)

src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.cs:38

• Variable is still named 'memoryStream' but the implementation is now StringStream (not a MemoryStream). Rename the local to avoid implying the stream is seekable/in-memory-buffered (e.g., 'xmlContentStream').

 Stream memoryStream = new StringStream(xmlContent, Encoding.UTF8);
object? xmlValue;
XmlDictionaryReaderQuotas? quotas = ((JsonReaderDelegator)jsonReader).ReaderQuotas;
if (quotas == null)
{
xmlValue = dataContractSerializer.ReadObject(memoryStream);

[Copilot]

Pull request overview

Copilot reviewed 23 out of 23 changed files in this pull request and generated 10 comments.

[Copilot]

Pull request overview

Copilot reviewed 23 out of 23 changed files in this pull request and generated 3 comments.

[Copilot]

Pull request overview

Copilot reviewed 28 out of 29 changed files in this pull request and generated 1 comment.

[SimonCropp]

awesome. that .net preview will this be in?

[jozkee]

/backport to release/11.0-preview6

[github-actions]

Started backporting to release/11.0-preview6 (link to workflow run)

[github-actions]

@jozkee backporting to release/11.0-preview6 failed, the patch most likely resulted in conflicts. Please backport manually!

git am output

$ git am --3way --empty=keep --ignore-whitespace --keep-non-patch changes.patchApplying: First API proposal implementationUsing index info to reconstruct a base tree...M	src/libraries/System.Memory/ref/System.Memory.csM	src/libraries/System.Memory/tests/System.Memory.Tests.csprojM	src/libraries/System.Private.CoreLib/src/Resources/Strings.resxM	src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitemsM	src/libraries/System.Runtime/ref/System.Runtime.csFalling back to patching base and 3-way merge...Auto-merging src/libraries/System.Memory/ref/System.Memory.csAuto-merging src/libraries/System.Memory/tests/System.Memory.Tests.csprojAuto-merging src/libraries/System.Private.CoreLib/src/Resources/Strings.resxAuto-merging src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitemsAuto-merging src/libraries/System.Runtime/ref/System.Runtime.csApplying: API replacements in production codeApplying: Implementation update based on latest API Review final consensusApplying: Address PR feedback. MemoryStream base change. Spillover buffer for Convert edge case. Flush strategy update.Applying: Address PR feedbackApplying: Address PR feedback: fix StringStream flush offset, WritableMemoryStream length/seek semantics, ReadOnlySequenceStream safety, and consolidate testsApplying: Address PR feedback: remove redundant code, improve test coverage and structureUsing index info to reconstruct a base tree...M	src/libraries/System.Memory/src/System/Buffers/ReadOnlySequenceStream.csM	src/libraries/System.Net.Http/src/System.Net.Http.csprojM	src/libraries/System.Private.CoreLib/src/System/IO/WritableMemoryStream.csM	src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.csM	src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamConformanceTests.csM	src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_Memory.csM	src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_String.csM	src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamConformanceTests.csM	src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamTests.csFalling back to patching base and 3-way merge...Auto-merging src/libraries/System.Memory/src/System/Buffers/ReadOnlySequenceStream.csAuto-merging src/libraries/System.Net.Http/src/System.Net.Http.csprojAuto-merging src/libraries/System.Private.CoreLib/src/System/IO/WritableMemoryStream.csAuto-merging src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.csCONFLICT (content): Merge conflict in src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamConformanceTests.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamConformanceTests.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_Memory.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_Memory.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_String.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_String.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamConformanceTests.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamConformanceTests.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamTests.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamTests.cserror: Failed to merge in the changes.hint: Use 'git am --show-current-patch=diff' to see the failed patchhint: When you have resolved this problem, run "git am --continue".hint: If you prefer to skip this patch, run "git am --skip" instead.hint: To restore the original branch and stop patching, run "git am --abort".hint: Disable this message with "git config set advice.mergeConflict false"Patch failed at 0007 Address PR feedback: remove redundant code, improve test coverage and structureError: The process '/usr/bin/git' failed with exit code 128

Link to workflow output

[ViveliDuCh]

Fixes#82801

Introduces standardized stream wrappers for text and memory types as public sealed classes (StringStream, ReadOnlyMemoryStream, WritableMemoryStream, and ReadOnlySequenceStream ) as approved in API review (video).

What's included

• StringStream (System.IO, CoreLib): non-seekable, read-only stream that encodes string or ReadOnlyMemory<char> on-the-fly. Encoding is required (no default). Never emits BOMs.
• ReadOnlyMemoryStream (System.IO, CoreLib): seekable, read-only stream over ReadOnlyMemory<byte>
• WritableMemoryStream (System.IO, CoreLib): seekable, read-write stream over Memory<byte> with fixed capacity
• ReadOnlySequenceStream (System.Buffers, System.Memory): seekable, read-only stream over ReadOnlySequence<byte>
• Ref assembly updates for System.Runtime and System.Memory
• Updated 3 internal call sites (ReadOnlyMemoryContent, XmlPreloadedResolver, JsonXmlDataContract) to use the new types
• Conformance and behavioral tests for all 4 types

Implementation notes

• All types are public sealed with direct constructors: the review moved away from factory methods on Stream to avoid derived-type IntelliSense noise
• StringStream encodes directly into the caller's buffer in Read() rather than using an internal byte buffer
• ReadOnlyMemoryStream and WritableMemoryStream derive from MemoryStream.
• TryGetBuffer returns false and GetBuffer throws on the memory stream types (no publiclyVisible support for now)

Limitations

• The internal shared-sourceReadOnlyMemoryStream in Common/ cannot be fully replaced:
  • System.Memory.Data multi-targets netstandard2.0 where the new public type doesn't exist.
  • System.Net.Http (net11.0 only) can adopt it directly.

Follow-up work

• IBufferWriter<byte> → Stream wrapper (separate proposal per #100434)

[Copilot]

Pull request overview

This PR introduces new standardized Stream wrapper types across CoreLib and System.Memory, aligning with the approved API shape from #82801 and updating a few internal call sites to use the new wrappers.

Changes:

• Added new public sealed stream wrappers: StringStream, ReadOnlyMemoryStream, WritableMemoryStream (CoreLib) and ReadOnlySequenceStream (System.Memory).
• Updated reference assemblies and project files to expose/compile the new APIs.
• Added conformance + targeted behavioral tests, and updated select internal consumers to use StringStream.

Reviewed changes

Copilot reviewed 23 out of 23 changed files in this pull request and generated 9 comments.

Show a summary per file

File	Description
src/libraries/System.Private.CoreLib/src/System/IO/StringStream.cs	Implements the new StringStream API (read-only, non-seekable, on-the-fly encoding).
src/libraries/System.Private.CoreLib/src/System/IO/ReadOnlyMemoryStream.cs	Implements seekable read-only stream over ReadOnlyMemory<byte>.
src/libraries/System.Private.CoreLib/src/System/IO/WritableMemoryStream.cs	Implements seekable fixed-capacity read/write stream over Memory<byte>.
src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitems	Wires new CoreLib stream wrapper source files into the build.
src/libraries/System.Private.CoreLib/src/Resources/Strings.resx	Adds a new resource string entry (currently appears unused).
src/libraries/System.Runtime/ref/System.Runtime.cs	Updates public API surface to include the new stream wrapper types (and a small ref signature normalization change).
src/libraries/System.Runtime/tests/System.IO.Tests/System.IO.Tests.csproj	Includes the new test files in the System.IO test project.
src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamConformanceTests.cs	Adds conformance coverage for StringStream (string + ReadOnlyMemory<char> overloads).
src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_String.cs	Adds targeted StringStream(string, Encoding) behavioral tests.
src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_Memory.cs	Adds targeted StringStream(ReadOnlyMemory<char>, Encoding) behavioral tests.
src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamConformanceTests.cs	Adds conformance coverage for ReadOnlyMemoryStream.
src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamTests.cs	Adds targeted ReadOnlyMemoryStream behavioral tests.
src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamConformanceTests.cs	Adds conformance coverage for WritableMemoryStream (with some overridden tests).
src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamTests.cs	Adds targeted WritableMemoryStream behavioral tests.
src/libraries/System.Memory/src/System/Buffers/ReadOnlySequenceStream.cs	Implements ReadOnlySequenceStream over ReadOnlySequence<byte>.
src/libraries/System.Memory/src/System.Memory.csproj	Includes the new ReadOnlySequenceStream source file in System.Memory.
src/libraries/System.Memory/src/Resources/Strings.resx	Adds SR strings needed for stream-like exception messages in System.Memory.
src/libraries/System.Memory/ref/System.Memory.cs	Adds ReadOnlySequenceStream to the System.Memory ref surface.
src/libraries/System.Memory/tests/System.Memory.Tests.csproj	Adds tests for ReadOnlySequenceStream and references StreamConformanceTests.
src/libraries/System.Memory/tests/ReadOnlyBuffer/ReadOnlySequenceStreamTests.cs	Adds targeted behavioral tests for multi-segment ReadOnlySequenceStream scenarios.
src/libraries/System.Memory/tests/ReadOnlyBuffer/ReadOnlySequenceStream.ConformanceTests.cs	Adds conformance coverage for ReadOnlySequenceStream.
src/libraries/System.Private.Xml/src/System/Xml/Resolvers/XmlPreloadedResolver.cs	Switches internal string-to-stream conversion to StringStream.
src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.cs	Switches internal string-to-stream conversion to StringStream.

Comments suppressed due to low confidence (1)

src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.cs:38

• Variable is still named 'memoryStream' but the implementation is now StringStream (not a MemoryStream). Rename the local to avoid implying the stream is seekable/in-memory-buffered (e.g., 'xmlContentStream').

 Stream memoryStream = new StringStream(xmlContent, Encoding.UTF8);
object? xmlValue;
XmlDictionaryReaderQuotas? quotas = ((JsonReaderDelegator)jsonReader).ReaderQuotas;
if (quotas == null)
{
xmlValue = dataContractSerializer.ReadObject(memoryStream);

[Copilot]

Pull request overview

Copilot reviewed 23 out of 23 changed files in this pull request and generated 10 comments.

[Copilot]

Pull request overview

Copilot reviewed 23 out of 23 changed files in this pull request and generated 3 comments.

[Copilot]

Pull request overview

Copilot reviewed 28 out of 29 changed files in this pull request and generated 1 comment.

[SimonCropp]

awesome. that .net preview will this be in?

[jozkee]

/backport to release/11.0-preview6

[github-actions]

Started backporting to release/11.0-preview6 (link to workflow run)

[github-actions]

@jozkee backporting to release/11.0-preview6 failed, the patch most likely resulted in conflicts. Please backport manually!

git am output

$ git am --3way --empty=keep --ignore-whitespace --keep-non-patch changes.patchApplying: First API proposal implementationUsing index info to reconstruct a base tree...M	src/libraries/System.Memory/ref/System.Memory.csM	src/libraries/System.Memory/tests/System.Memory.Tests.csprojM	src/libraries/System.Private.CoreLib/src/Resources/Strings.resxM	src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitemsM	src/libraries/System.Runtime/ref/System.Runtime.csFalling back to patching base and 3-way merge...Auto-merging src/libraries/System.Memory/ref/System.Memory.csAuto-merging src/libraries/System.Memory/tests/System.Memory.Tests.csprojAuto-merging src/libraries/System.Private.CoreLib/src/Resources/Strings.resxAuto-merging src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitemsAuto-merging src/libraries/System.Runtime/ref/System.Runtime.csApplying: API replacements in production codeApplying: Implementation update based on latest API Review final consensusApplying: Address PR feedback. MemoryStream base change. Spillover buffer for Convert edge case. Flush strategy update.Applying: Address PR feedbackApplying: Address PR feedback: fix StringStream flush offset, WritableMemoryStream length/seek semantics, ReadOnlySequenceStream safety, and consolidate testsApplying: Address PR feedback: remove redundant code, improve test coverage and structureUsing index info to reconstruct a base tree...M	src/libraries/System.Memory/src/System/Buffers/ReadOnlySequenceStream.csM	src/libraries/System.Net.Http/src/System.Net.Http.csprojM	src/libraries/System.Private.CoreLib/src/System/IO/WritableMemoryStream.csM	src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.csM	src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamConformanceTests.csM	src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_Memory.csM	src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_String.csM	src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamConformanceTests.csM	src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamTests.csFalling back to patching base and 3-way merge...Auto-merging src/libraries/System.Memory/src/System/Buffers/ReadOnlySequenceStream.csAuto-merging src/libraries/System.Net.Http/src/System.Net.Http.csprojAuto-merging src/libraries/System.Private.CoreLib/src/System/IO/WritableMemoryStream.csAuto-merging src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.csCONFLICT (content): Merge conflict in src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamConformanceTests.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamConformanceTests.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_Memory.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_Memory.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_String.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_String.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamConformanceTests.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamConformanceTests.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamTests.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamTests.cserror: Failed to merge in the changes.hint: Use 'git am --show-current-patch=diff' to see the failed patchhint: When you have resolved this problem, run "git am --continue".hint: If you prefer to skip this patch, run "git am --skip" instead.hint: To restore the original branch and stop patching, run "git am --abort".hint: Disable this message with "git config set advice.mergeConflict false"Patch failed at 0007 Address PR feedback: remove redundant code, improve test coverage and structureError: The process '/usr/bin/git' failed with exit code 128

Link to workflow output

[ViveliDuCh]

Fixes#82801

Introduces standardized stream wrappers for text and memory types as public sealed classes (StringStream, ReadOnlyMemoryStream, WritableMemoryStream, and ReadOnlySequenceStream ) as approved in API review (video).

What's included

• StringStream (System.IO, CoreLib): non-seekable, read-only stream that encodes string or ReadOnlyMemory<char> on-the-fly. Encoding is required (no default). Never emits BOMs.
• ReadOnlyMemoryStream (System.IO, CoreLib): seekable, read-only stream over ReadOnlyMemory<byte>
• WritableMemoryStream (System.IO, CoreLib): seekable, read-write stream over Memory<byte> with fixed capacity
• ReadOnlySequenceStream (System.Buffers, System.Memory): seekable, read-only stream over ReadOnlySequence<byte>
• Ref assembly updates for System.Runtime and System.Memory
• Updated 3 internal call sites (ReadOnlyMemoryContent, XmlPreloadedResolver, JsonXmlDataContract) to use the new types
• Conformance and behavioral tests for all 4 types

Implementation notes

• All types are public sealed with direct constructors: the review moved away from factory methods on Stream to avoid derived-type IntelliSense noise
• StringStream encodes directly into the caller's buffer in Read() rather than using an internal byte buffer
• ReadOnlyMemoryStream and WritableMemoryStream derive from MemoryStream.
• TryGetBuffer returns false and GetBuffer throws on the memory stream types (no publiclyVisible support for now)

Limitations

• The internal shared-sourceReadOnlyMemoryStream in Common/ cannot be fully replaced:
  • System.Memory.Data multi-targets netstandard2.0 where the new public type doesn't exist.
  • System.Net.Http (net11.0 only) can adopt it directly.

Follow-up work

• IBufferWriter<byte> → Stream wrapper (separate proposal per #100434)

[Copilot]

Pull request overview

This PR introduces new standardized Stream wrapper types across CoreLib and System.Memory, aligning with the approved API shape from #82801 and updating a few internal call sites to use the new wrappers.

Changes:

• Added new public sealed stream wrappers: StringStream, ReadOnlyMemoryStream, WritableMemoryStream (CoreLib) and ReadOnlySequenceStream (System.Memory).
• Updated reference assemblies and project files to expose/compile the new APIs.
• Added conformance + targeted behavioral tests, and updated select internal consumers to use StringStream.

Reviewed changes

Copilot reviewed 23 out of 23 changed files in this pull request and generated 9 comments.

Show a summary per file

File	Description
src/libraries/System.Private.CoreLib/src/System/IO/StringStream.cs	Implements the new StringStream API (read-only, non-seekable, on-the-fly encoding).
src/libraries/System.Private.CoreLib/src/System/IO/ReadOnlyMemoryStream.cs	Implements seekable read-only stream over ReadOnlyMemory<byte>.
src/libraries/System.Private.CoreLib/src/System/IO/WritableMemoryStream.cs	Implements seekable fixed-capacity read/write stream over Memory<byte>.
src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitems	Wires new CoreLib stream wrapper source files into the build.
src/libraries/System.Private.CoreLib/src/Resources/Strings.resx	Adds a new resource string entry (currently appears unused).
src/libraries/System.Runtime/ref/System.Runtime.cs	Updates public API surface to include the new stream wrapper types (and a small ref signature normalization change).
src/libraries/System.Runtime/tests/System.IO.Tests/System.IO.Tests.csproj	Includes the new test files in the System.IO test project.
src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamConformanceTests.cs	Adds conformance coverage for StringStream (string + ReadOnlyMemory<char> overloads).
src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_String.cs	Adds targeted StringStream(string, Encoding) behavioral tests.
src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_Memory.cs	Adds targeted StringStream(ReadOnlyMemory<char>, Encoding) behavioral tests.
src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamConformanceTests.cs	Adds conformance coverage for ReadOnlyMemoryStream.
src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamTests.cs	Adds targeted ReadOnlyMemoryStream behavioral tests.
src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamConformanceTests.cs	Adds conformance coverage for WritableMemoryStream (with some overridden tests).
src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamTests.cs	Adds targeted WritableMemoryStream behavioral tests.
src/libraries/System.Memory/src/System/Buffers/ReadOnlySequenceStream.cs	Implements ReadOnlySequenceStream over ReadOnlySequence<byte>.
src/libraries/System.Memory/src/System.Memory.csproj	Includes the new ReadOnlySequenceStream source file in System.Memory.
src/libraries/System.Memory/src/Resources/Strings.resx	Adds SR strings needed for stream-like exception messages in System.Memory.
src/libraries/System.Memory/ref/System.Memory.cs	Adds ReadOnlySequenceStream to the System.Memory ref surface.
src/libraries/System.Memory/tests/System.Memory.Tests.csproj	Adds tests for ReadOnlySequenceStream and references StreamConformanceTests.
src/libraries/System.Memory/tests/ReadOnlyBuffer/ReadOnlySequenceStreamTests.cs	Adds targeted behavioral tests for multi-segment ReadOnlySequenceStream scenarios.
src/libraries/System.Memory/tests/ReadOnlyBuffer/ReadOnlySequenceStream.ConformanceTests.cs	Adds conformance coverage for ReadOnlySequenceStream.
src/libraries/System.Private.Xml/src/System/Xml/Resolvers/XmlPreloadedResolver.cs	Switches internal string-to-stream conversion to StringStream.
src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.cs	Switches internal string-to-stream conversion to StringStream.

Comments suppressed due to low confidence (1)

src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.cs:38

• Variable is still named 'memoryStream' but the implementation is now StringStream (not a MemoryStream). Rename the local to avoid implying the stream is seekable/in-memory-buffered (e.g., 'xmlContentStream').

 Stream memoryStream = new StringStream(xmlContent, Encoding.UTF8);
object? xmlValue;
XmlDictionaryReaderQuotas? quotas = ((JsonReaderDelegator)jsonReader).ReaderQuotas;
if (quotas == null)
{
xmlValue = dataContractSerializer.ReadObject(memoryStream);

[Copilot]

Pull request overview

Copilot reviewed 23 out of 23 changed files in this pull request and generated 10 comments.

[Copilot]

Pull request overview

Copilot reviewed 23 out of 23 changed files in this pull request and generated 3 comments.

[Copilot]

Pull request overview

Copilot reviewed 28 out of 29 changed files in this pull request and generated 1 comment.

[SimonCropp]

awesome. that .net preview will this be in?

[jozkee]

/backport to release/11.0-preview6

[github-actions]

Started backporting to release/11.0-preview6 (link to workflow run)

[github-actions]

@jozkee backporting to release/11.0-preview6 failed, the patch most likely resulted in conflicts. Please backport manually!

git am output

$ git am --3way --empty=keep --ignore-whitespace --keep-non-patch changes.patchApplying: First API proposal implementationUsing index info to reconstruct a base tree...M	src/libraries/System.Memory/ref/System.Memory.csM	src/libraries/System.Memory/tests/System.Memory.Tests.csprojM	src/libraries/System.Private.CoreLib/src/Resources/Strings.resxM	src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitemsM	src/libraries/System.Runtime/ref/System.Runtime.csFalling back to patching base and 3-way merge...Auto-merging src/libraries/System.Memory/ref/System.Memory.csAuto-merging src/libraries/System.Memory/tests/System.Memory.Tests.csprojAuto-merging src/libraries/System.Private.CoreLib/src/Resources/Strings.resxAuto-merging src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitemsAuto-merging src/libraries/System.Runtime/ref/System.Runtime.csApplying: API replacements in production codeApplying: Implementation update based on latest API Review final consensusApplying: Address PR feedback. MemoryStream base change. Spillover buffer for Convert edge case. Flush strategy update.Applying: Address PR feedbackApplying: Address PR feedback: fix StringStream flush offset, WritableMemoryStream length/seek semantics, ReadOnlySequenceStream safety, and consolidate testsApplying: Address PR feedback: remove redundant code, improve test coverage and structureUsing index info to reconstruct a base tree...M	src/libraries/System.Memory/src/System/Buffers/ReadOnlySequenceStream.csM	src/libraries/System.Net.Http/src/System.Net.Http.csprojM	src/libraries/System.Private.CoreLib/src/System/IO/WritableMemoryStream.csM	src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.csM	src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamConformanceTests.csM	src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_Memory.csM	src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_String.csM	src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamConformanceTests.csM	src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamTests.csFalling back to patching base and 3-way merge...Auto-merging src/libraries/System.Memory/src/System/Buffers/ReadOnlySequenceStream.csAuto-merging src/libraries/System.Net.Http/src/System.Net.Http.csprojAuto-merging src/libraries/System.Private.CoreLib/src/System/IO/WritableMemoryStream.csAuto-merging src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.csCONFLICT (content): Merge conflict in src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamConformanceTests.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamConformanceTests.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_Memory.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_Memory.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_String.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_String.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamConformanceTests.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamConformanceTests.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamTests.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamTests.cserror: Failed to merge in the changes.hint: Use 'git am --show-current-patch=diff' to see the failed patchhint: When you have resolved this problem, run "git am --continue".hint: If you prefer to skip this patch, run "git am --skip" instead.hint: To restore the original branch and stop patching, run "git am --abort".hint: Disable this message with "git config set advice.mergeConflict false"Patch failed at 0007 Address PR feedback: remove redundant code, improve test coverage and structureError: The process '/usr/bin/git' failed with exit code 128

Link to workflow output

[ViveliDuCh]

Fixes#82801

Introduces standardized stream wrappers for text and memory types as public sealed classes (StringStream, ReadOnlyMemoryStream, WritableMemoryStream, and ReadOnlySequenceStream ) as approved in API review (video).

What's included

• StringStream (System.IO, CoreLib): non-seekable, read-only stream that encodes string or ReadOnlyMemory<char> on-the-fly. Encoding is required (no default). Never emits BOMs.
• ReadOnlyMemoryStream (System.IO, CoreLib): seekable, read-only stream over ReadOnlyMemory<byte>
• WritableMemoryStream (System.IO, CoreLib): seekable, read-write stream over Memory<byte> with fixed capacity
• ReadOnlySequenceStream (System.Buffers, System.Memory): seekable, read-only stream over ReadOnlySequence<byte>
• Ref assembly updates for System.Runtime and System.Memory
• Updated 3 internal call sites (ReadOnlyMemoryContent, XmlPreloadedResolver, JsonXmlDataContract) to use the new types
• Conformance and behavioral tests for all 4 types

Implementation notes

• All types are public sealed with direct constructors: the review moved away from factory methods on Stream to avoid derived-type IntelliSense noise
• StringStream encodes directly into the caller's buffer in Read() rather than using an internal byte buffer
• ReadOnlyMemoryStream and WritableMemoryStream derive from MemoryStream.
• TryGetBuffer returns false and GetBuffer throws on the memory stream types (no publiclyVisible support for now)

Limitations

• The internal shared-sourceReadOnlyMemoryStream in Common/ cannot be fully replaced:
  • System.Memory.Data multi-targets netstandard2.0 where the new public type doesn't exist.
  • System.Net.Http (net11.0 only) can adopt it directly.

Follow-up work

• IBufferWriter<byte> → Stream wrapper (separate proposal per #100434)

[Copilot]

Pull request overview

This PR introduces new standardized Stream wrapper types across CoreLib and System.Memory, aligning with the approved API shape from #82801 and updating a few internal call sites to use the new wrappers.

Changes:

• Added new public sealed stream wrappers: StringStream, ReadOnlyMemoryStream, WritableMemoryStream (CoreLib) and ReadOnlySequenceStream (System.Memory).
• Updated reference assemblies and project files to expose/compile the new APIs.
• Added conformance + targeted behavioral tests, and updated select internal consumers to use StringStream.

Reviewed changes

Copilot reviewed 23 out of 23 changed files in this pull request and generated 9 comments.

Show a summary per file

File	Description
src/libraries/System.Private.CoreLib/src/System/IO/StringStream.cs	Implements the new StringStream API (read-only, non-seekable, on-the-fly encoding).
src/libraries/System.Private.CoreLib/src/System/IO/ReadOnlyMemoryStream.cs	Implements seekable read-only stream over ReadOnlyMemory<byte>.
src/libraries/System.Private.CoreLib/src/System/IO/WritableMemoryStream.cs	Implements seekable fixed-capacity read/write stream over Memory<byte>.
src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitems	Wires new CoreLib stream wrapper source files into the build.
src/libraries/System.Private.CoreLib/src/Resources/Strings.resx	Adds a new resource string entry (currently appears unused).
src/libraries/System.Runtime/ref/System.Runtime.cs	Updates public API surface to include the new stream wrapper types (and a small ref signature normalization change).
src/libraries/System.Runtime/tests/System.IO.Tests/System.IO.Tests.csproj	Includes the new test files in the System.IO test project.
src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamConformanceTests.cs	Adds conformance coverage for StringStream (string + ReadOnlyMemory<char> overloads).
src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_String.cs	Adds targeted StringStream(string, Encoding) behavioral tests.
src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_Memory.cs	Adds targeted StringStream(ReadOnlyMemory<char>, Encoding) behavioral tests.
src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamConformanceTests.cs	Adds conformance coverage for ReadOnlyMemoryStream.
src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamTests.cs	Adds targeted ReadOnlyMemoryStream behavioral tests.
src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamConformanceTests.cs	Adds conformance coverage for WritableMemoryStream (with some overridden tests).
src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamTests.cs	Adds targeted WritableMemoryStream behavioral tests.
src/libraries/System.Memory/src/System/Buffers/ReadOnlySequenceStream.cs	Implements ReadOnlySequenceStream over ReadOnlySequence<byte>.
src/libraries/System.Memory/src/System.Memory.csproj	Includes the new ReadOnlySequenceStream source file in System.Memory.
src/libraries/System.Memory/src/Resources/Strings.resx	Adds SR strings needed for stream-like exception messages in System.Memory.
src/libraries/System.Memory/ref/System.Memory.cs	Adds ReadOnlySequenceStream to the System.Memory ref surface.
src/libraries/System.Memory/tests/System.Memory.Tests.csproj	Adds tests for ReadOnlySequenceStream and references StreamConformanceTests.
src/libraries/System.Memory/tests/ReadOnlyBuffer/ReadOnlySequenceStreamTests.cs	Adds targeted behavioral tests for multi-segment ReadOnlySequenceStream scenarios.
src/libraries/System.Memory/tests/ReadOnlyBuffer/ReadOnlySequenceStream.ConformanceTests.cs	Adds conformance coverage for ReadOnlySequenceStream.
src/libraries/System.Private.Xml/src/System/Xml/Resolvers/XmlPreloadedResolver.cs	Switches internal string-to-stream conversion to StringStream.
src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.cs	Switches internal string-to-stream conversion to StringStream.

Comments suppressed due to low confidence (1)

src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.cs:38

• Variable is still named 'memoryStream' but the implementation is now StringStream (not a MemoryStream). Rename the local to avoid implying the stream is seekable/in-memory-buffered (e.g., 'xmlContentStream').

 Stream memoryStream = new StringStream(xmlContent, Encoding.UTF8);
object? xmlValue;
XmlDictionaryReaderQuotas? quotas = ((JsonReaderDelegator)jsonReader).ReaderQuotas;
if (quotas == null)
{
xmlValue = dataContractSerializer.ReadObject(memoryStream);

[Copilot]

Pull request overview

Copilot reviewed 23 out of 23 changed files in this pull request and generated 10 comments.

[Copilot]

Pull request overview

Copilot reviewed 23 out of 23 changed files in this pull request and generated 3 comments.

[Copilot]

Pull request overview

Copilot reviewed 28 out of 29 changed files in this pull request and generated 1 comment.

[SimonCropp]

awesome. that .net preview will this be in?

[jozkee]

/backport to release/11.0-preview6

[github-actions]

Started backporting to release/11.0-preview6 (link to workflow run)

[github-actions]

@jozkee backporting to release/11.0-preview6 failed, the patch most likely resulted in conflicts. Please backport manually!

git am output

$ git am --3way --empty=keep --ignore-whitespace --keep-non-patch changes.patchApplying: First API proposal implementationUsing index info to reconstruct a base tree...M	src/libraries/System.Memory/ref/System.Memory.csM	src/libraries/System.Memory/tests/System.Memory.Tests.csprojM	src/libraries/System.Private.CoreLib/src/Resources/Strings.resxM	src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitemsM	src/libraries/System.Runtime/ref/System.Runtime.csFalling back to patching base and 3-way merge...Auto-merging src/libraries/System.Memory/ref/System.Memory.csAuto-merging src/libraries/System.Memory/tests/System.Memory.Tests.csprojAuto-merging src/libraries/System.Private.CoreLib/src/Resources/Strings.resxAuto-merging src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitemsAuto-merging src/libraries/System.Runtime/ref/System.Runtime.csApplying: API replacements in production codeApplying: Implementation update based on latest API Review final consensusApplying: Address PR feedback. MemoryStream base change. Spillover buffer for Convert edge case. Flush strategy update.Applying: Address PR feedbackApplying: Address PR feedback: fix StringStream flush offset, WritableMemoryStream length/seek semantics, ReadOnlySequenceStream safety, and consolidate testsApplying: Address PR feedback: remove redundant code, improve test coverage and structureUsing index info to reconstruct a base tree...M	src/libraries/System.Memory/src/System/Buffers/ReadOnlySequenceStream.csM	src/libraries/System.Net.Http/src/System.Net.Http.csprojM	src/libraries/System.Private.CoreLib/src/System/IO/WritableMemoryStream.csM	src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.csM	src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamConformanceTests.csM	src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_Memory.csM	src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_String.csM	src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamConformanceTests.csM	src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamTests.csFalling back to patching base and 3-way merge...Auto-merging src/libraries/System.Memory/src/System/Buffers/ReadOnlySequenceStream.csAuto-merging src/libraries/System.Net.Http/src/System.Net.Http.csprojAuto-merging src/libraries/System.Private.CoreLib/src/System/IO/WritableMemoryStream.csAuto-merging src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.csCONFLICT (content): Merge conflict in src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamConformanceTests.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamConformanceTests.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_Memory.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_Memory.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_String.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_String.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamConformanceTests.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamConformanceTests.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamTests.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamTests.cserror: Failed to merge in the changes.hint: Use 'git am --show-current-patch=diff' to see the failed patchhint: When you have resolved this problem, run "git am --continue".hint: If you prefer to skip this patch, run "git am --skip" instead.hint: To restore the original branch and stop patching, run "git am --abort".hint: Disable this message with "git config set advice.mergeConflict false"Patch failed at 0007 Address PR feedback: remove redundant code, improve test coverage and structureError: The process '/usr/bin/git' failed with exit code 128

Link to workflow output

[ViveliDuCh]

Fixes#82801

Introduces standardized stream wrappers for text and memory types as public sealed classes (StringStream, ReadOnlyMemoryStream, WritableMemoryStream, and ReadOnlySequenceStream ) as approved in API review (video).

What's included

• StringStream (System.IO, CoreLib): non-seekable, read-only stream that encodes string or ReadOnlyMemory<char> on-the-fly. Encoding is required (no default). Never emits BOMs.
• ReadOnlyMemoryStream (System.IO, CoreLib): seekable, read-only stream over ReadOnlyMemory<byte>
• WritableMemoryStream (System.IO, CoreLib): seekable, read-write stream over Memory<byte> with fixed capacity
• ReadOnlySequenceStream (System.Buffers, System.Memory): seekable, read-only stream over ReadOnlySequence<byte>
• Ref assembly updates for System.Runtime and System.Memory
• Updated 3 internal call sites (ReadOnlyMemoryContent, XmlPreloadedResolver, JsonXmlDataContract) to use the new types
• Conformance and behavioral tests for all 4 types

Implementation notes

• All types are public sealed with direct constructors: the review moved away from factory methods on Stream to avoid derived-type IntelliSense noise
• StringStream encodes directly into the caller's buffer in Read() rather than using an internal byte buffer
• ReadOnlyMemoryStream and WritableMemoryStream derive from MemoryStream.
• TryGetBuffer returns false and GetBuffer throws on the memory stream types (no publiclyVisible support for now)

Limitations

• The internal shared-sourceReadOnlyMemoryStream in Common/ cannot be fully replaced:
  • System.Memory.Data multi-targets netstandard2.0 where the new public type doesn't exist.
  • System.Net.Http (net11.0 only) can adopt it directly.

Follow-up work

• IBufferWriter<byte> → Stream wrapper (separate proposal per #100434)

[Copilot]

Pull request overview

This PR introduces new standardized Stream wrapper types across CoreLib and System.Memory, aligning with the approved API shape from #82801 and updating a few internal call sites to use the new wrappers.

Changes:

• Added new public sealed stream wrappers: StringStream, ReadOnlyMemoryStream, WritableMemoryStream (CoreLib) and ReadOnlySequenceStream (System.Memory).
• Updated reference assemblies and project files to expose/compile the new APIs.
• Added conformance + targeted behavioral tests, and updated select internal consumers to use StringStream.

Reviewed changes

Copilot reviewed 23 out of 23 changed files in this pull request and generated 9 comments.

Show a summary per file

File	Description
src/libraries/System.Private.CoreLib/src/System/IO/StringStream.cs	Implements the new StringStream API (read-only, non-seekable, on-the-fly encoding).
src/libraries/System.Private.CoreLib/src/System/IO/ReadOnlyMemoryStream.cs	Implements seekable read-only stream over ReadOnlyMemory<byte>.
src/libraries/System.Private.CoreLib/src/System/IO/WritableMemoryStream.cs	Implements seekable fixed-capacity read/write stream over Memory<byte>.
src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitems	Wires new CoreLib stream wrapper source files into the build.
src/libraries/System.Private.CoreLib/src/Resources/Strings.resx	Adds a new resource string entry (currently appears unused).
src/libraries/System.Runtime/ref/System.Runtime.cs	Updates public API surface to include the new stream wrapper types (and a small ref signature normalization change).
src/libraries/System.Runtime/tests/System.IO.Tests/System.IO.Tests.csproj	Includes the new test files in the System.IO test project.
src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamConformanceTests.cs	Adds conformance coverage for StringStream (string + ReadOnlyMemory<char> overloads).
src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_String.cs	Adds targeted StringStream(string, Encoding) behavioral tests.
src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_Memory.cs	Adds targeted StringStream(ReadOnlyMemory<char>, Encoding) behavioral tests.
src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamConformanceTests.cs	Adds conformance coverage for ReadOnlyMemoryStream.
src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamTests.cs	Adds targeted ReadOnlyMemoryStream behavioral tests.
src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamConformanceTests.cs	Adds conformance coverage for WritableMemoryStream (with some overridden tests).
src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamTests.cs	Adds targeted WritableMemoryStream behavioral tests.
src/libraries/System.Memory/src/System/Buffers/ReadOnlySequenceStream.cs	Implements ReadOnlySequenceStream over ReadOnlySequence<byte>.
src/libraries/System.Memory/src/System.Memory.csproj	Includes the new ReadOnlySequenceStream source file in System.Memory.
src/libraries/System.Memory/src/Resources/Strings.resx	Adds SR strings needed for stream-like exception messages in System.Memory.
src/libraries/System.Memory/ref/System.Memory.cs	Adds ReadOnlySequenceStream to the System.Memory ref surface.
src/libraries/System.Memory/tests/System.Memory.Tests.csproj	Adds tests for ReadOnlySequenceStream and references StreamConformanceTests.
src/libraries/System.Memory/tests/ReadOnlyBuffer/ReadOnlySequenceStreamTests.cs	Adds targeted behavioral tests for multi-segment ReadOnlySequenceStream scenarios.
src/libraries/System.Memory/tests/ReadOnlyBuffer/ReadOnlySequenceStream.ConformanceTests.cs	Adds conformance coverage for ReadOnlySequenceStream.
src/libraries/System.Private.Xml/src/System/Xml/Resolvers/XmlPreloadedResolver.cs	Switches internal string-to-stream conversion to StringStream.
src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.cs	Switches internal string-to-stream conversion to StringStream.

Comments suppressed due to low confidence (1)

src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.cs:38

• Variable is still named 'memoryStream' but the implementation is now StringStream (not a MemoryStream). Rename the local to avoid implying the stream is seekable/in-memory-buffered (e.g., 'xmlContentStream').

 Stream memoryStream = new StringStream(xmlContent, Encoding.UTF8);
object? xmlValue;
XmlDictionaryReaderQuotas? quotas = ((JsonReaderDelegator)jsonReader).ReaderQuotas;
if (quotas == null)
{
xmlValue = dataContractSerializer.ReadObject(memoryStream);

[Copilot]

Pull request overview

Copilot reviewed 23 out of 23 changed files in this pull request and generated 10 comments.

[Copilot]

Pull request overview

Copilot reviewed 23 out of 23 changed files in this pull request and generated 3 comments.

[Copilot]

Pull request overview

Copilot reviewed 28 out of 29 changed files in this pull request and generated 1 comment.

[SimonCropp]

awesome. that .net preview will this be in?

[jozkee]

/backport to release/11.0-preview6

[github-actions]

Started backporting to release/11.0-preview6 (link to workflow run)

[github-actions]

@jozkee backporting to release/11.0-preview6 failed, the patch most likely resulted in conflicts. Please backport manually!

git am output

$ git am --3way --empty=keep --ignore-whitespace --keep-non-patch changes.patchApplying: First API proposal implementationUsing index info to reconstruct a base tree...M	src/libraries/System.Memory/ref/System.Memory.csM	src/libraries/System.Memory/tests/System.Memory.Tests.csprojM	src/libraries/System.Private.CoreLib/src/Resources/Strings.resxM	src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitemsM	src/libraries/System.Runtime/ref/System.Runtime.csFalling back to patching base and 3-way merge...Auto-merging src/libraries/System.Memory/ref/System.Memory.csAuto-merging src/libraries/System.Memory/tests/System.Memory.Tests.csprojAuto-merging src/libraries/System.Private.CoreLib/src/Resources/Strings.resxAuto-merging src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitemsAuto-merging src/libraries/System.Runtime/ref/System.Runtime.csApplying: API replacements in production codeApplying: Implementation update based on latest API Review final consensusApplying: Address PR feedback. MemoryStream base change. Spillover buffer for Convert edge case. Flush strategy update.Applying: Address PR feedbackApplying: Address PR feedback: fix StringStream flush offset, WritableMemoryStream length/seek semantics, ReadOnlySequenceStream safety, and consolidate testsApplying: Address PR feedback: remove redundant code, improve test coverage and structureUsing index info to reconstruct a base tree...M	src/libraries/System.Memory/src/System/Buffers/ReadOnlySequenceStream.csM	src/libraries/System.Net.Http/src/System.Net.Http.csprojM	src/libraries/System.Private.CoreLib/src/System/IO/WritableMemoryStream.csM	src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.csM	src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamConformanceTests.csM	src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_Memory.csM	src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_String.csM	src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamConformanceTests.csM	src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamTests.csFalling back to patching base and 3-way merge...Auto-merging src/libraries/System.Memory/src/System/Buffers/ReadOnlySequenceStream.csAuto-merging src/libraries/System.Net.Http/src/System.Net.Http.csprojAuto-merging src/libraries/System.Private.CoreLib/src/System/IO/WritableMemoryStream.csAuto-merging src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.csCONFLICT (content): Merge conflict in src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamConformanceTests.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamConformanceTests.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_Memory.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_Memory.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_String.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_String.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamConformanceTests.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamConformanceTests.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamTests.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamTests.cserror: Failed to merge in the changes.hint: Use 'git am --show-current-patch=diff' to see the failed patchhint: When you have resolved this problem, run "git am --continue".hint: If you prefer to skip this patch, run "git am --skip" instead.hint: To restore the original branch and stop patching, run "git am --abort".hint: Disable this message with "git config set advice.mergeConflict false"Patch failed at 0007 Address PR feedback: remove redundant code, improve test coverage and structureError: The process '/usr/bin/git' failed with exit code 128

Link to workflow output

[ViveliDuCh]

Fixes#82801

Introduces standardized stream wrappers for text and memory types as public sealed classes (StringStream, ReadOnlyMemoryStream, WritableMemoryStream, and ReadOnlySequenceStream ) as approved in API review (video).

What's included

• StringStream (System.IO, CoreLib): non-seekable, read-only stream that encodes string or ReadOnlyMemory<char> on-the-fly. Encoding is required (no default). Never emits BOMs.
• ReadOnlyMemoryStream (System.IO, CoreLib): seekable, read-only stream over ReadOnlyMemory<byte>
• WritableMemoryStream (System.IO, CoreLib): seekable, read-write stream over Memory<byte> with fixed capacity
• ReadOnlySequenceStream (System.Buffers, System.Memory): seekable, read-only stream over ReadOnlySequence<byte>
• Ref assembly updates for System.Runtime and System.Memory
• Updated 3 internal call sites (ReadOnlyMemoryContent, XmlPreloadedResolver, JsonXmlDataContract) to use the new types
• Conformance and behavioral tests for all 4 types

Implementation notes

• All types are public sealed with direct constructors: the review moved away from factory methods on Stream to avoid derived-type IntelliSense noise
• StringStream encodes directly into the caller's buffer in Read() rather than using an internal byte buffer
• ReadOnlyMemoryStream and WritableMemoryStream derive from MemoryStream.
• TryGetBuffer returns false and GetBuffer throws on the memory stream types (no publiclyVisible support for now)

Limitations

• The internal shared-sourceReadOnlyMemoryStream in Common/ cannot be fully replaced:
  • System.Memory.Data multi-targets netstandard2.0 where the new public type doesn't exist.
  • System.Net.Http (net11.0 only) can adopt it directly.

Follow-up work

• IBufferWriter<byte> → Stream wrapper (separate proposal per #100434)

[Copilot]

Pull request overview

This PR introduces new standardized Stream wrapper types across CoreLib and System.Memory, aligning with the approved API shape from #82801 and updating a few internal call sites to use the new wrappers.

Changes:

• Added new public sealed stream wrappers: StringStream, ReadOnlyMemoryStream, WritableMemoryStream (CoreLib) and ReadOnlySequenceStream (System.Memory).
• Updated reference assemblies and project files to expose/compile the new APIs.
• Added conformance + targeted behavioral tests, and updated select internal consumers to use StringStream.

Reviewed changes

Copilot reviewed 23 out of 23 changed files in this pull request and generated 9 comments.

Show a summary per file

File	Description
src/libraries/System.Private.CoreLib/src/System/IO/StringStream.cs	Implements the new StringStream API (read-only, non-seekable, on-the-fly encoding).
src/libraries/System.Private.CoreLib/src/System/IO/ReadOnlyMemoryStream.cs	Implements seekable read-only stream over ReadOnlyMemory<byte>.
src/libraries/System.Private.CoreLib/src/System/IO/WritableMemoryStream.cs	Implements seekable fixed-capacity read/write stream over Memory<byte>.
src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitems	Wires new CoreLib stream wrapper source files into the build.
src/libraries/System.Private.CoreLib/src/Resources/Strings.resx	Adds a new resource string entry (currently appears unused).
src/libraries/System.Runtime/ref/System.Runtime.cs	Updates public API surface to include the new stream wrapper types (and a small ref signature normalization change).
src/libraries/System.Runtime/tests/System.IO.Tests/System.IO.Tests.csproj	Includes the new test files in the System.IO test project.
src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamConformanceTests.cs	Adds conformance coverage for StringStream (string + ReadOnlyMemory<char> overloads).
src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_String.cs	Adds targeted StringStream(string, Encoding) behavioral tests.
src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_Memory.cs	Adds targeted StringStream(ReadOnlyMemory<char>, Encoding) behavioral tests.
src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamConformanceTests.cs	Adds conformance coverage for ReadOnlyMemoryStream.
src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamTests.cs	Adds targeted ReadOnlyMemoryStream behavioral tests.
src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamConformanceTests.cs	Adds conformance coverage for WritableMemoryStream (with some overridden tests).
src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamTests.cs	Adds targeted WritableMemoryStream behavioral tests.
src/libraries/System.Memory/src/System/Buffers/ReadOnlySequenceStream.cs	Implements ReadOnlySequenceStream over ReadOnlySequence<byte>.
src/libraries/System.Memory/src/System.Memory.csproj	Includes the new ReadOnlySequenceStream source file in System.Memory.
src/libraries/System.Memory/src/Resources/Strings.resx	Adds SR strings needed for stream-like exception messages in System.Memory.
src/libraries/System.Memory/ref/System.Memory.cs	Adds ReadOnlySequenceStream to the System.Memory ref surface.
src/libraries/System.Memory/tests/System.Memory.Tests.csproj	Adds tests for ReadOnlySequenceStream and references StreamConformanceTests.
src/libraries/System.Memory/tests/ReadOnlyBuffer/ReadOnlySequenceStreamTests.cs	Adds targeted behavioral tests for multi-segment ReadOnlySequenceStream scenarios.
src/libraries/System.Memory/tests/ReadOnlyBuffer/ReadOnlySequenceStream.ConformanceTests.cs	Adds conformance coverage for ReadOnlySequenceStream.
src/libraries/System.Private.Xml/src/System/Xml/Resolvers/XmlPreloadedResolver.cs	Switches internal string-to-stream conversion to StringStream.
src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.cs	Switches internal string-to-stream conversion to StringStream.

Comments suppressed due to low confidence (1)

src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.cs:38

• Variable is still named 'memoryStream' but the implementation is now StringStream (not a MemoryStream). Rename the local to avoid implying the stream is seekable/in-memory-buffered (e.g., 'xmlContentStream').

 Stream memoryStream = new StringStream(xmlContent, Encoding.UTF8);
object? xmlValue;
XmlDictionaryReaderQuotas? quotas = ((JsonReaderDelegator)jsonReader).ReaderQuotas;
if (quotas == null)
{
xmlValue = dataContractSerializer.ReadObject(memoryStream);

[Copilot]

Pull request overview

Copilot reviewed 23 out of 23 changed files in this pull request and generated 10 comments.

[Copilot]

Pull request overview

Copilot reviewed 23 out of 23 changed files in this pull request and generated 3 comments.

[Copilot]

Pull request overview

Copilot reviewed 28 out of 29 changed files in this pull request and generated 1 comment.

[SimonCropp]

awesome. that .net preview will this be in?

[jozkee]

/backport to release/11.0-preview6

[github-actions]

Started backporting to release/11.0-preview6 (link to workflow run)

[github-actions]

@jozkee backporting to release/11.0-preview6 failed, the patch most likely resulted in conflicts. Please backport manually!

git am output

$ git am --3way --empty=keep --ignore-whitespace --keep-non-patch changes.patchApplying: First API proposal implementationUsing index info to reconstruct a base tree...M	src/libraries/System.Memory/ref/System.Memory.csM	src/libraries/System.Memory/tests/System.Memory.Tests.csprojM	src/libraries/System.Private.CoreLib/src/Resources/Strings.resxM	src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitemsM	src/libraries/System.Runtime/ref/System.Runtime.csFalling back to patching base and 3-way merge...Auto-merging src/libraries/System.Memory/ref/System.Memory.csAuto-merging src/libraries/System.Memory/tests/System.Memory.Tests.csprojAuto-merging src/libraries/System.Private.CoreLib/src/Resources/Strings.resxAuto-merging src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitemsAuto-merging src/libraries/System.Runtime/ref/System.Runtime.csApplying: API replacements in production codeApplying: Implementation update based on latest API Review final consensusApplying: Address PR feedback. MemoryStream base change. Spillover buffer for Convert edge case. Flush strategy update.Applying: Address PR feedbackApplying: Address PR feedback: fix StringStream flush offset, WritableMemoryStream length/seek semantics, ReadOnlySequenceStream safety, and consolidate testsApplying: Address PR feedback: remove redundant code, improve test coverage and structureUsing index info to reconstruct a base tree...M	src/libraries/System.Memory/src/System/Buffers/ReadOnlySequenceStream.csM	src/libraries/System.Net.Http/src/System.Net.Http.csprojM	src/libraries/System.Private.CoreLib/src/System/IO/WritableMemoryStream.csM	src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.csM	src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamConformanceTests.csM	src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_Memory.csM	src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_String.csM	src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamConformanceTests.csM	src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamTests.csFalling back to patching base and 3-way merge...Auto-merging src/libraries/System.Memory/src/System/Buffers/ReadOnlySequenceStream.csAuto-merging src/libraries/System.Net.Http/src/System.Net.Http.csprojAuto-merging src/libraries/System.Private.CoreLib/src/System/IO/WritableMemoryStream.csAuto-merging src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.csCONFLICT (content): Merge conflict in src/libraries/System.Private.DataContractSerialization/src/System/Runtime/Serialization/Json/JsonXmlDataContract.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamConformanceTests.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/ReadOnlyMemoryStream/ReadOnlyMemoryStreamConformanceTests.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_Memory.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_Memory.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_String.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/StringStream/StringStreamTests_String.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamConformanceTests.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamConformanceTests.csAuto-merging src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamTests.csCONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.IO.Tests/WritableMemoryStream/WritableMemoryStreamTests.cserror: Failed to merge in the changes.hint: Use 'git am --show-current-patch=diff' to see the failed patchhint: When you have resolved this problem, run "git am --continue".hint: If you prefer to skip this patch, run "git am --skip" instead.hint: To restore the original branch and stop patching, run "git am --abort".hint: Disable this message with "git config set advice.mergeConflict false"Patch failed at 0007 Address PR feedback: remove redundant code, improve test coverage and structureError: The process '/usr/bin/git' failed with exit code 128

Link to workflow output