Implement ProcessStartInfo.KillOnParentExit for Windows by Copilot · Pull Request #126699 · dotnet/runtime

Copilot · 2026-04-09T11:20:47Z

Description

Implements the ProcessStartInfo.KillOnParentExit property for Windows, which terminates child processes when the parent process exits. This is the Windows part of the KillOnParentExit feature.

API approved at #125838 (comment)

Changes Made

New API surface:

Added KillOnParentExit property to ProcessStartInfo with [SupportedOSPlatform("windows")] attribute (linux support will be added in upcoming PRs)
Added to reference assembly (ref/System.Diagnostics.Process.cs) with matching [SupportedOSPlatformAttribute("windows")]
Added XML documentation with a link to the Windows SDK description of JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE

Windows implementation (SafeProcessHandle.Windows.cs):

Added a lazily-initialized static SafeJobHandle with JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE flag, shared across all child processes with KillOnParentExit=true
For CreateProcess path (no user credentials): uses PROC_THREAD_ATTRIBUTE_JOB_LIST in the extended startup info for atomic job assignment at process creation
For CreateProcessWithLogonW path (with user credentials): starts the process suspended, assigns it to the job object via AssignProcessToJobObject, then resumes the thread only on the happy path — on failure, the suspended process is terminated
ResumeThread return value is checked; failure throws Win32Exception and the suspended process is terminated
AssignJobAndResumeThread takes (IntPtr hThread, SafeProcessHandle procSH) and uses procSH consistently for all process handle operations (no mixing of processInfo.hProcess and procSH)
ConfigureExtendedStartupInfo returns bool and the caller sets creationFlags, startupInfoEx.StartupInfo.cb, and startupInfoEx.lpAttributeList to reduce the number of method arguments
Uses string.IsNullOrEmpty(startInfo.UserName) for defensive checks when determining the code path

P/Invoke definitions:

Interop.JobObjects.cs: CreateJobObjectW, SetInformationJobObject, AssignProcessToJobObject (accepts SafeProcessHandle), JOBOBJECT_EXTENDED_LIMIT_INFORMATION, IO_COUNTERS, JOBOBJECTINFOCLASS structs/enums, SafeJobHandle, PROC_THREAD_ATTRIBUTE_JOB_LIST constant
Interop.ResumeThread.cs: ResumeThread P/Invoke returning uint (matching native DWORD) in its own dedicated file (following the pattern of Interop.TerminateProcess.cs, Interop.GetExitCodeProcess.cs, etc.)
IO_COUNTERS and JOBOBJECT_EXTENDED_LIMIT_INFORMATION use nuint for fields representing numerical values (sizes, limits, affinity masks) per interop convention
Replaced the local ResumeThread P/Invoke in ProcessHandlesTests.Windows.cs with the shared Interop.Kernel32.ResumeThread, eliminating the duplicate declaration and aligning the test code with the production uint/0xFFFFFFFF pattern

Validation:

Extended ProcessStartInfo.ThrowIfInvalid to throw InvalidOperationException when KillOnParentExit is combined with UseShellExecute
Added KillOnParentExitCannotBeUsedWithUseShellExecute string resource

Tests (KillOnParentExitTests.cs):

KillOnParentExit_DefaultsToFalse / KillOnParentExit_CanBeSetToTrue — property basics
KillOnParentExit_WithUseShellExecute_Throws — validation test
KillOnParentExit_ProcessStartsAndExitsNormally — smoke test
KillOnParentExit_KillsTheChild_WhenParentExits — verifies child is killed (enabled=true) or survives (enabled=false) on normal parent exit, reports grandchild pid via stdout
KillOnParentExit_KillsTheChild_WhenParentIsKilled — same when parent is forcefully killed
KillOnParentExit_KillsTheChild_WhenParentCrashes — same when parent crashes (access violation)
User credentials code path is exercised via the updated ProcessStartInfoTests.TestUserCredentialsPropertiesOnWindows (admin/OuterLoop)

Add KillOnParentExit property to ProcessStartInfo that terminates child processes when the parent process exits. Windows implementation uses Job Objects with JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE flag. For CreateProcess: uses PROC_THREAD_ATTRIBUTE_JOB_LIST for atomic assignment. For CreateProcessWithLogonW: starts suspended, assigns to job, then resumes. Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/61612ca1-930c-4836-8554-d143d05c8321 Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

adamsitnik

@copilot address my feedback

…py path, add user credentials test, fix pid reporting via stdout, remove nop UseShellExecute test Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/c4dd95b4-cd8e-4740-83f9-7358444c04ce Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

Copilot · 2026-04-09T12:51:22Z

@copilot address my feedback

All feedback addressed in 31f6e6b. All 403 tests pass.

- simplify the tests - avoid duplication!!

Copilot

Pull request overview

Implements Windows support for ProcessStartInfo.KillOnParentExit by using Windows Job Objects to ensure spawned processes are terminated when the parent exits.

Changes:

Added ProcessStartInfo.KillOnParentExit API surface (implementation + ref assembly) and validation against UseShellExecute.
Implemented Windows job-object based process start paths (CreateProcess job-list attribute, and CreateProcessWithLogonW suspended + assign + resume).
Added Windows-focused tests validating the behavior.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
src/libraries/System.Diagnostics.Process/tests/System.Diagnostics.Process.Tests.csproj	Includes the new KillOnParentExit test file in the test project.
src/libraries/System.Diagnostics.Process/tests/ProcessStartInfoTests.cs	Extends existing Windows credential tests to cover KillOnParentExit on that path.
src/libraries/System.Diagnostics.Process/tests/KillOnParentExitTests.cs	Adds new Windows tests validating KillOnParentExit behavior under various parent-exit scenarios.
src/libraries/System.Diagnostics.Process/src/System/Diagnostics/ProcessStartInfo.cs	Adds the KillOnParentExit property, docs, and validation with UseShellExecute.
src/libraries/System.Diagnostics.Process/src/System.Diagnostics.Process.csproj	Links in the new Windows job-object interop file.
src/libraries/System.Diagnostics.Process/src/Resources/Strings.resx	Adds a resource string for the KillOnParentExit + UseShellExecute validation.
src/libraries/System.Diagnostics.Process/src/Microsoft/Win32/SafeHandles/SafeProcessHandle.Windows.cs	Windows implementation: shared job handle, job-list attribute support, and logon path job assignment.
src/libraries/System.Diagnostics.Process/ref/System.Diagnostics.Process.cs	Adds the KillOnParentExit property to the reference assembly surface.
src/libraries/Common/src/Interop/Windows/Kernel32/Interop.JobObjects.cs	Adds required job-object P/Invokes/structs/constants.
src/libraries/Common/src/Interop/Windows/Advapi32/Interop.ProcessOptions.cs	Adds CREATE_SUSPENDED for the CreateProcessWithLogonW suspended-start path.

adamsitnik

@copilot address my feedback

…sumeThread return, remove unused using, improve VerifyProcessIsRunning polling Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/06c58cfa-bdef-4f35-9345-9ab03e7dc542 Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

Copilot · 2026-04-09T16:17:49Z

@copilot address my feedback

All feedback addressed in cc04598. Source builds and all 401 tests pass.

jkotas · 2026-04-11T14:10:07Z

ProcessHandlesTests.Windows.cs (line 187) has a local private static partial int ResumeThread(nint hThread) with == -1 check. This is technically correct (same bit pattern) but inconsistent with the production code's uint/0xFFFFFFFF pattern.

@copilot Address this feedback by replacing the local ResumeThread with the shared copy

…d Interop.Kernel32.ResumeThread Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/e8bb36bc-5c71-4723-a32c-17e87d762370 Co-authored-by: jkotas <6668460+jkotas@users.noreply.github.com>

Copilot · 2026-04-11T14:20:09Z

ProcessHandlesTests.Windows.cs (line 187) has a local private static partial int ResumeThread(nint hThread) with == -1 check. This is technically correct (same bit pattern) but inconsistent with the...

Replaced the local ResumeThread P/Invoke in ProcessHandlesTests.Windows.cs with the shared Interop.Kernel32.ResumeThread (returns uint, check == 0xFFFFFFFF) in c5b7d59. Also added the Interop.ResumeThread.cs reference to the test csproj.

…al ResumeThread P/Invoke Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/e8bb36bc-5c71-4723-a32c-17e87d762370 Co-authored-by: jkotas <6668460+jkotas@users.noreply.github.com>

Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/f3703368-dbc7-4226-8258-1bb793d93faf Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

adamsitnik · 2026-04-11T19:25:17Z

@copilot please address @jkotas feedback

…, unnecessary assert, reduce ConfigureExtendedStartupInfo args Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/2dd25b7c-da4a-4ed0-a9b3-cc6561f14aeb Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

Copilot · 2026-04-11T19:35:05Z

@copilot please address @jkotas feedback

All four items addressed in f497166.

Copilot · 2026-04-09T11:20:47Z

Description

Implements the ProcessStartInfo.KillOnParentExit property for Windows, which terminates child processes when the parent process exits. This is the Windows part of the KillOnParentExit feature.

API approved at #125838 (comment)

Changes Made

New API surface:

Added KillOnParentExit property to ProcessStartInfo with [SupportedOSPlatform("windows")] attribute (linux support will be added in upcoming PRs)
Added to reference assembly (ref/System.Diagnostics.Process.cs) with matching [SupportedOSPlatformAttribute("windows")]
Added XML documentation with a link to the Windows SDK description of JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE

Windows implementation (SafeProcessHandle.Windows.cs):

Added a lazily-initialized static SafeJobHandle with JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE flag, shared across all child processes with KillOnParentExit=true
For CreateProcess path (no user credentials): uses PROC_THREAD_ATTRIBUTE_JOB_LIST in the extended startup info for atomic job assignment at process creation
For CreateProcessWithLogonW path (with user credentials): starts the process suspended, assigns it to the job object via AssignProcessToJobObject, then resumes the thread only on the happy path — on failure, the suspended process is terminated
ResumeThread return value is checked; failure throws Win32Exception and the suspended process is terminated
AssignJobAndResumeThread takes (IntPtr hThread, SafeProcessHandle procSH) and uses procSH consistently for all process handle operations (no mixing of processInfo.hProcess and procSH)
ConfigureExtendedStartupInfo returns bool and the caller sets creationFlags, startupInfoEx.StartupInfo.cb, and startupInfoEx.lpAttributeList to reduce the number of method arguments
Uses string.IsNullOrEmpty(startInfo.UserName) for defensive checks when determining the code path

P/Invoke definitions:

Interop.JobObjects.cs: CreateJobObjectW, SetInformationJobObject, AssignProcessToJobObject (accepts SafeProcessHandle), JOBOBJECT_EXTENDED_LIMIT_INFORMATION, IO_COUNTERS, JOBOBJECTINFOCLASS structs/enums, SafeJobHandle, PROC_THREAD_ATTRIBUTE_JOB_LIST constant
Interop.ResumeThread.cs: ResumeThread P/Invoke returning uint (matching native DWORD) in its own dedicated file (following the pattern of Interop.TerminateProcess.cs, Interop.GetExitCodeProcess.cs, etc.)
IO_COUNTERS and JOBOBJECT_EXTENDED_LIMIT_INFORMATION use nuint for fields representing numerical values (sizes, limits, affinity masks) per interop convention
Replaced the local ResumeThread P/Invoke in ProcessHandlesTests.Windows.cs with the shared Interop.Kernel32.ResumeThread, eliminating the duplicate declaration and aligning the test code with the production uint/0xFFFFFFFF pattern

Validation:

Extended ProcessStartInfo.ThrowIfInvalid to throw InvalidOperationException when KillOnParentExit is combined with UseShellExecute
Added KillOnParentExitCannotBeUsedWithUseShellExecute string resource

Tests (KillOnParentExitTests.cs):

KillOnParentExit_DefaultsToFalse / KillOnParentExit_CanBeSetToTrue — property basics
KillOnParentExit_WithUseShellExecute_Throws — validation test
KillOnParentExit_ProcessStartsAndExitsNormally — smoke test
KillOnParentExit_KillsTheChild_WhenParentExits — verifies child is killed (enabled=true) or survives (enabled=false) on normal parent exit, reports grandchild pid via stdout
KillOnParentExit_KillsTheChild_WhenParentIsKilled — same when parent is forcefully killed
KillOnParentExit_KillsTheChild_WhenParentCrashes — same when parent crashes (access violation)
User credentials code path is exercised via the updated ProcessStartInfoTests.TestUserCredentialsPropertiesOnWindows (admin/OuterLoop)

Add KillOnParentExit property to ProcessStartInfo that terminates child processes when the parent process exits. Windows implementation uses Job Objects with JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE flag. For CreateProcess: uses PROC_THREAD_ATTRIBUTE_JOB_LIST for atomic assignment. For CreateProcessWithLogonW: starts suspended, assigns to job, then resumes. Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/61612ca1-930c-4836-8554-d143d05c8321 Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

adamsitnik

@copilot address my feedback

…py path, add user credentials test, fix pid reporting via stdout, remove nop UseShellExecute test Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/c4dd95b4-cd8e-4740-83f9-7358444c04ce Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

Copilot · 2026-04-09T12:51:22Z

@copilot address my feedback

All feedback addressed in 31f6e6b. All 403 tests pass.

- simplify the tests - avoid duplication!!

Copilot

Pull request overview

Implements Windows support for ProcessStartInfo.KillOnParentExit by using Windows Job Objects to ensure spawned processes are terminated when the parent exits.

Changes:

Added ProcessStartInfo.KillOnParentExit API surface (implementation + ref assembly) and validation against UseShellExecute.
Implemented Windows job-object based process start paths (CreateProcess job-list attribute, and CreateProcessWithLogonW suspended + assign + resume).
Added Windows-focused tests validating the behavior.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
src/libraries/System.Diagnostics.Process/tests/System.Diagnostics.Process.Tests.csproj	Includes the new KillOnParentExit test file in the test project.
src/libraries/System.Diagnostics.Process/tests/ProcessStartInfoTests.cs	Extends existing Windows credential tests to cover KillOnParentExit on that path.
src/libraries/System.Diagnostics.Process/tests/KillOnParentExitTests.cs	Adds new Windows tests validating KillOnParentExit behavior under various parent-exit scenarios.
src/libraries/System.Diagnostics.Process/src/System/Diagnostics/ProcessStartInfo.cs	Adds the KillOnParentExit property, docs, and validation with UseShellExecute.
src/libraries/System.Diagnostics.Process/src/System.Diagnostics.Process.csproj	Links in the new Windows job-object interop file.
src/libraries/System.Diagnostics.Process/src/Resources/Strings.resx	Adds a resource string for the KillOnParentExit + UseShellExecute validation.
src/libraries/System.Diagnostics.Process/src/Microsoft/Win32/SafeHandles/SafeProcessHandle.Windows.cs	Windows implementation: shared job handle, job-list attribute support, and logon path job assignment.
src/libraries/System.Diagnostics.Process/ref/System.Diagnostics.Process.cs	Adds the KillOnParentExit property to the reference assembly surface.
src/libraries/Common/src/Interop/Windows/Kernel32/Interop.JobObjects.cs	Adds required job-object P/Invokes/structs/constants.
src/libraries/Common/src/Interop/Windows/Advapi32/Interop.ProcessOptions.cs	Adds CREATE_SUSPENDED for the CreateProcessWithLogonW suspended-start path.

adamsitnik

@copilot address my feedback

…sumeThread return, remove unused using, improve VerifyProcessIsRunning polling Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/06c58cfa-bdef-4f35-9345-9ab03e7dc542 Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

Copilot · 2026-04-09T16:17:49Z

@copilot address my feedback

All feedback addressed in cc04598. Source builds and all 401 tests pass.

jkotas · 2026-04-11T14:10:07Z

ProcessHandlesTests.Windows.cs (line 187) has a local private static partial int ResumeThread(nint hThread) with == -1 check. This is technically correct (same bit pattern) but inconsistent with the production code's uint/0xFFFFFFFF pattern.

@copilot Address this feedback by replacing the local ResumeThread with the shared copy

…d Interop.Kernel32.ResumeThread Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/e8bb36bc-5c71-4723-a32c-17e87d762370 Co-authored-by: jkotas <6668460+jkotas@users.noreply.github.com>

Copilot · 2026-04-11T14:20:09Z

ProcessHandlesTests.Windows.cs (line 187) has a local private static partial int ResumeThread(nint hThread) with == -1 check. This is technically correct (same bit pattern) but inconsistent with the...

Replaced the local ResumeThread P/Invoke in ProcessHandlesTests.Windows.cs with the shared Interop.Kernel32.ResumeThread (returns uint, check == 0xFFFFFFFF) in c5b7d59. Also added the Interop.ResumeThread.cs reference to the test csproj.

…al ResumeThread P/Invoke Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/e8bb36bc-5c71-4723-a32c-17e87d762370 Co-authored-by: jkotas <6668460+jkotas@users.noreply.github.com>

Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/f3703368-dbc7-4226-8258-1bb793d93faf Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

adamsitnik · 2026-04-11T19:25:17Z

@copilot please address @jkotas feedback

…, unnecessary assert, reduce ConfigureExtendedStartupInfo args Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/2dd25b7c-da4a-4ed0-a9b3-cc6561f14aeb Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

Copilot · 2026-04-11T19:35:05Z

@copilot please address @jkotas feedback

All four items addressed in f497166.

Copilot · 2026-04-09T11:20:47Z

Description

Implements the ProcessStartInfo.KillOnParentExit property for Windows, which terminates child processes when the parent process exits. This is the Windows part of the KillOnParentExit feature.

API approved at #125838 (comment)

Changes Made

New API surface:

Added KillOnParentExit property to ProcessStartInfo with [SupportedOSPlatform("windows")] attribute (linux support will be added in upcoming PRs)
Added to reference assembly (ref/System.Diagnostics.Process.cs) with matching [SupportedOSPlatformAttribute("windows")]
Added XML documentation with a link to the Windows SDK description of JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE

Windows implementation (SafeProcessHandle.Windows.cs):

Added a lazily-initialized static SafeJobHandle with JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE flag, shared across all child processes with KillOnParentExit=true
For CreateProcess path (no user credentials): uses PROC_THREAD_ATTRIBUTE_JOB_LIST in the extended startup info for atomic job assignment at process creation
For CreateProcessWithLogonW path (with user credentials): starts the process suspended, assigns it to the job object via AssignProcessToJobObject, then resumes the thread only on the happy path — on failure, the suspended process is terminated
ResumeThread return value is checked; failure throws Win32Exception and the suspended process is terminated
AssignJobAndResumeThread takes (IntPtr hThread, SafeProcessHandle procSH) and uses procSH consistently for all process handle operations (no mixing of processInfo.hProcess and procSH)
ConfigureExtendedStartupInfo returns bool and the caller sets creationFlags, startupInfoEx.StartupInfo.cb, and startupInfoEx.lpAttributeList to reduce the number of method arguments
Uses string.IsNullOrEmpty(startInfo.UserName) for defensive checks when determining the code path

P/Invoke definitions:

Interop.JobObjects.cs: CreateJobObjectW, SetInformationJobObject, AssignProcessToJobObject (accepts SafeProcessHandle), JOBOBJECT_EXTENDED_LIMIT_INFORMATION, IO_COUNTERS, JOBOBJECTINFOCLASS structs/enums, SafeJobHandle, PROC_THREAD_ATTRIBUTE_JOB_LIST constant
Interop.ResumeThread.cs: ResumeThread P/Invoke returning uint (matching native DWORD) in its own dedicated file (following the pattern of Interop.TerminateProcess.cs, Interop.GetExitCodeProcess.cs, etc.)
IO_COUNTERS and JOBOBJECT_EXTENDED_LIMIT_INFORMATION use nuint for fields representing numerical values (sizes, limits, affinity masks) per interop convention
Replaced the local ResumeThread P/Invoke in ProcessHandlesTests.Windows.cs with the shared Interop.Kernel32.ResumeThread, eliminating the duplicate declaration and aligning the test code with the production uint/0xFFFFFFFF pattern

Validation:

Extended ProcessStartInfo.ThrowIfInvalid to throw InvalidOperationException when KillOnParentExit is combined with UseShellExecute
Added KillOnParentExitCannotBeUsedWithUseShellExecute string resource

Tests (KillOnParentExitTests.cs):

KillOnParentExit_DefaultsToFalse / KillOnParentExit_CanBeSetToTrue — property basics
KillOnParentExit_WithUseShellExecute_Throws — validation test
KillOnParentExit_ProcessStartsAndExitsNormally — smoke test
KillOnParentExit_KillsTheChild_WhenParentExits — verifies child is killed (enabled=true) or survives (enabled=false) on normal parent exit, reports grandchild pid via stdout
KillOnParentExit_KillsTheChild_WhenParentIsKilled — same when parent is forcefully killed
KillOnParentExit_KillsTheChild_WhenParentCrashes — same when parent crashes (access violation)
User credentials code path is exercised via the updated ProcessStartInfoTests.TestUserCredentialsPropertiesOnWindows (admin/OuterLoop)

Add KillOnParentExit property to ProcessStartInfo that terminates child processes when the parent process exits. Windows implementation uses Job Objects with JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE flag. For CreateProcess: uses PROC_THREAD_ATTRIBUTE_JOB_LIST for atomic assignment. For CreateProcessWithLogonW: starts suspended, assigns to job, then resumes. Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/61612ca1-930c-4836-8554-d143d05c8321 Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

adamsitnik

@copilot address my feedback

…py path, add user credentials test, fix pid reporting via stdout, remove nop UseShellExecute test Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/c4dd95b4-cd8e-4740-83f9-7358444c04ce Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

Copilot · 2026-04-09T12:51:22Z

@copilot address my feedback

All feedback addressed in 31f6e6b. All 403 tests pass.

- simplify the tests - avoid duplication!!

Copilot

Pull request overview

Implements Windows support for ProcessStartInfo.KillOnParentExit by using Windows Job Objects to ensure spawned processes are terminated when the parent exits.

Changes:

Added ProcessStartInfo.KillOnParentExit API surface (implementation + ref assembly) and validation against UseShellExecute.
Implemented Windows job-object based process start paths (CreateProcess job-list attribute, and CreateProcessWithLogonW suspended + assign + resume).
Added Windows-focused tests validating the behavior.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
src/libraries/System.Diagnostics.Process/tests/System.Diagnostics.Process.Tests.csproj	Includes the new KillOnParentExit test file in the test project.
src/libraries/System.Diagnostics.Process/tests/ProcessStartInfoTests.cs	Extends existing Windows credential tests to cover KillOnParentExit on that path.
src/libraries/System.Diagnostics.Process/tests/KillOnParentExitTests.cs	Adds new Windows tests validating KillOnParentExit behavior under various parent-exit scenarios.
src/libraries/System.Diagnostics.Process/src/System/Diagnostics/ProcessStartInfo.cs	Adds the KillOnParentExit property, docs, and validation with UseShellExecute.
src/libraries/System.Diagnostics.Process/src/System.Diagnostics.Process.csproj	Links in the new Windows job-object interop file.
src/libraries/System.Diagnostics.Process/src/Resources/Strings.resx	Adds a resource string for the KillOnParentExit + UseShellExecute validation.
src/libraries/System.Diagnostics.Process/src/Microsoft/Win32/SafeHandles/SafeProcessHandle.Windows.cs	Windows implementation: shared job handle, job-list attribute support, and logon path job assignment.
src/libraries/System.Diagnostics.Process/ref/System.Diagnostics.Process.cs	Adds the KillOnParentExit property to the reference assembly surface.
src/libraries/Common/src/Interop/Windows/Kernel32/Interop.JobObjects.cs	Adds required job-object P/Invokes/structs/constants.
src/libraries/Common/src/Interop/Windows/Advapi32/Interop.ProcessOptions.cs	Adds CREATE_SUSPENDED for the CreateProcessWithLogonW suspended-start path.

adamsitnik

@copilot address my feedback

…sumeThread return, remove unused using, improve VerifyProcessIsRunning polling Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/06c58cfa-bdef-4f35-9345-9ab03e7dc542 Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

Copilot · 2026-04-09T16:17:49Z

@copilot address my feedback

All feedback addressed in cc04598. Source builds and all 401 tests pass.

jkotas · 2026-04-11T14:10:07Z

ProcessHandlesTests.Windows.cs (line 187) has a local private static partial int ResumeThread(nint hThread) with == -1 check. This is technically correct (same bit pattern) but inconsistent with the production code's uint/0xFFFFFFFF pattern.

@copilot Address this feedback by replacing the local ResumeThread with the shared copy

…d Interop.Kernel32.ResumeThread Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/e8bb36bc-5c71-4723-a32c-17e87d762370 Co-authored-by: jkotas <6668460+jkotas@users.noreply.github.com>

Copilot · 2026-04-11T14:20:09Z

ProcessHandlesTests.Windows.cs (line 187) has a local private static partial int ResumeThread(nint hThread) with == -1 check. This is technically correct (same bit pattern) but inconsistent with the...

Replaced the local ResumeThread P/Invoke in ProcessHandlesTests.Windows.cs with the shared Interop.Kernel32.ResumeThread (returns uint, check == 0xFFFFFFFF) in c5b7d59. Also added the Interop.ResumeThread.cs reference to the test csproj.

…al ResumeThread P/Invoke Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/e8bb36bc-5c71-4723-a32c-17e87d762370 Co-authored-by: jkotas <6668460+jkotas@users.noreply.github.com>

Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/f3703368-dbc7-4226-8258-1bb793d93faf Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

adamsitnik · 2026-04-11T19:25:17Z

@copilot please address @jkotas feedback

…, unnecessary assert, reduce ConfigureExtendedStartupInfo args Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/2dd25b7c-da4a-4ed0-a9b3-cc6561f14aeb Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

Copilot · 2026-04-11T19:35:05Z

@copilot please address @jkotas feedback

All four items addressed in f497166.

Copilot · 2026-04-09T11:20:47Z

Description

Implements the ProcessStartInfo.KillOnParentExit property for Windows, which terminates child processes when the parent process exits. This is the Windows part of the KillOnParentExit feature.

API approved at #125838 (comment)

Changes Made

New API surface:

Added KillOnParentExit property to ProcessStartInfo with [SupportedOSPlatform("windows")] attribute (linux support will be added in upcoming PRs)
Added to reference assembly (ref/System.Diagnostics.Process.cs) with matching [SupportedOSPlatformAttribute("windows")]
Added XML documentation with a link to the Windows SDK description of JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE

Windows implementation (SafeProcessHandle.Windows.cs):

Added a lazily-initialized static SafeJobHandle with JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE flag, shared across all child processes with KillOnParentExit=true
For CreateProcess path (no user credentials): uses PROC_THREAD_ATTRIBUTE_JOB_LIST in the extended startup info for atomic job assignment at process creation
For CreateProcessWithLogonW path (with user credentials): starts the process suspended, assigns it to the job object via AssignProcessToJobObject, then resumes the thread only on the happy path — on failure, the suspended process is terminated
ResumeThread return value is checked; failure throws Win32Exception and the suspended process is terminated
AssignJobAndResumeThread takes (IntPtr hThread, SafeProcessHandle procSH) and uses procSH consistently for all process handle operations (no mixing of processInfo.hProcess and procSH)
ConfigureExtendedStartupInfo returns bool and the caller sets creationFlags, startupInfoEx.StartupInfo.cb, and startupInfoEx.lpAttributeList to reduce the number of method arguments
Uses string.IsNullOrEmpty(startInfo.UserName) for defensive checks when determining the code path

P/Invoke definitions:

Interop.JobObjects.cs: CreateJobObjectW, SetInformationJobObject, AssignProcessToJobObject (accepts SafeProcessHandle), JOBOBJECT_EXTENDED_LIMIT_INFORMATION, IO_COUNTERS, JOBOBJECTINFOCLASS structs/enums, SafeJobHandle, PROC_THREAD_ATTRIBUTE_JOB_LIST constant
Interop.ResumeThread.cs: ResumeThread P/Invoke returning uint (matching native DWORD) in its own dedicated file (following the pattern of Interop.TerminateProcess.cs, Interop.GetExitCodeProcess.cs, etc.)
IO_COUNTERS and JOBOBJECT_EXTENDED_LIMIT_INFORMATION use nuint for fields representing numerical values (sizes, limits, affinity masks) per interop convention
Replaced the local ResumeThread P/Invoke in ProcessHandlesTests.Windows.cs with the shared Interop.Kernel32.ResumeThread, eliminating the duplicate declaration and aligning the test code with the production uint/0xFFFFFFFF pattern

Validation:

Extended ProcessStartInfo.ThrowIfInvalid to throw InvalidOperationException when KillOnParentExit is combined with UseShellExecute
Added KillOnParentExitCannotBeUsedWithUseShellExecute string resource

Tests (KillOnParentExitTests.cs):

KillOnParentExit_DefaultsToFalse / KillOnParentExit_CanBeSetToTrue — property basics
KillOnParentExit_WithUseShellExecute_Throws — validation test
KillOnParentExit_ProcessStartsAndExitsNormally — smoke test
KillOnParentExit_KillsTheChild_WhenParentExits — verifies child is killed (enabled=true) or survives (enabled=false) on normal parent exit, reports grandchild pid via stdout
KillOnParentExit_KillsTheChild_WhenParentIsKilled — same when parent is forcefully killed
KillOnParentExit_KillsTheChild_WhenParentCrashes — same when parent crashes (access violation)
User credentials code path is exercised via the updated ProcessStartInfoTests.TestUserCredentialsPropertiesOnWindows (admin/OuterLoop)

Add KillOnParentExit property to ProcessStartInfo that terminates child processes when the parent process exits. Windows implementation uses Job Objects with JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE flag. For CreateProcess: uses PROC_THREAD_ATTRIBUTE_JOB_LIST for atomic assignment. For CreateProcessWithLogonW: starts suspended, assigns to job, then resumes. Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/61612ca1-930c-4836-8554-d143d05c8321 Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

adamsitnik

@copilot address my feedback

…py path, add user credentials test, fix pid reporting via stdout, remove nop UseShellExecute test Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/c4dd95b4-cd8e-4740-83f9-7358444c04ce Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

Copilot · 2026-04-09T12:51:22Z

@copilot address my feedback

All feedback addressed in 31f6e6b. All 403 tests pass.

- simplify the tests - avoid duplication!!

Copilot

Pull request overview

Implements Windows support for ProcessStartInfo.KillOnParentExit by using Windows Job Objects to ensure spawned processes are terminated when the parent exits.

Changes:

Added ProcessStartInfo.KillOnParentExit API surface (implementation + ref assembly) and validation against UseShellExecute.
Implemented Windows job-object based process start paths (CreateProcess job-list attribute, and CreateProcessWithLogonW suspended + assign + resume).
Added Windows-focused tests validating the behavior.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
src/libraries/System.Diagnostics.Process/tests/System.Diagnostics.Process.Tests.csproj	Includes the new KillOnParentExit test file in the test project.
src/libraries/System.Diagnostics.Process/tests/ProcessStartInfoTests.cs	Extends existing Windows credential tests to cover KillOnParentExit on that path.
src/libraries/System.Diagnostics.Process/tests/KillOnParentExitTests.cs	Adds new Windows tests validating KillOnParentExit behavior under various parent-exit scenarios.
src/libraries/System.Diagnostics.Process/src/System/Diagnostics/ProcessStartInfo.cs	Adds the KillOnParentExit property, docs, and validation with UseShellExecute.
src/libraries/System.Diagnostics.Process/src/System.Diagnostics.Process.csproj	Links in the new Windows job-object interop file.
src/libraries/System.Diagnostics.Process/src/Resources/Strings.resx	Adds a resource string for the KillOnParentExit + UseShellExecute validation.
src/libraries/System.Diagnostics.Process/src/Microsoft/Win32/SafeHandles/SafeProcessHandle.Windows.cs	Windows implementation: shared job handle, job-list attribute support, and logon path job assignment.
src/libraries/System.Diagnostics.Process/ref/System.Diagnostics.Process.cs	Adds the KillOnParentExit property to the reference assembly surface.
src/libraries/Common/src/Interop/Windows/Kernel32/Interop.JobObjects.cs	Adds required job-object P/Invokes/structs/constants.
src/libraries/Common/src/Interop/Windows/Advapi32/Interop.ProcessOptions.cs	Adds CREATE_SUSPENDED for the CreateProcessWithLogonW suspended-start path.

adamsitnik

@copilot address my feedback

…sumeThread return, remove unused using, improve VerifyProcessIsRunning polling Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/06c58cfa-bdef-4f35-9345-9ab03e7dc542 Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

Copilot · 2026-04-09T16:17:49Z

@copilot address my feedback

All feedback addressed in cc04598. Source builds and all 401 tests pass.

jkotas · 2026-04-11T14:10:07Z

ProcessHandlesTests.Windows.cs (line 187) has a local private static partial int ResumeThread(nint hThread) with == -1 check. This is technically correct (same bit pattern) but inconsistent with the production code's uint/0xFFFFFFFF pattern.

@copilot Address this feedback by replacing the local ResumeThread with the shared copy

…d Interop.Kernel32.ResumeThread Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/e8bb36bc-5c71-4723-a32c-17e87d762370 Co-authored-by: jkotas <6668460+jkotas@users.noreply.github.com>

Copilot · 2026-04-11T14:20:09Z

ProcessHandlesTests.Windows.cs (line 187) has a local private static partial int ResumeThread(nint hThread) with == -1 check. This is technically correct (same bit pattern) but inconsistent with the...

Replaced the local ResumeThread P/Invoke in ProcessHandlesTests.Windows.cs with the shared Interop.Kernel32.ResumeThread (returns uint, check == 0xFFFFFFFF) in c5b7d59. Also added the Interop.ResumeThread.cs reference to the test csproj.

…al ResumeThread P/Invoke Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/e8bb36bc-5c71-4723-a32c-17e87d762370 Co-authored-by: jkotas <6668460+jkotas@users.noreply.github.com>

Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/f3703368-dbc7-4226-8258-1bb793d93faf Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

adamsitnik · 2026-04-11T19:25:17Z

@copilot please address @jkotas feedback

…, unnecessary assert, reduce ConfigureExtendedStartupInfo args Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/2dd25b7c-da4a-4ed0-a9b3-cc6561f14aeb Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

Copilot · 2026-04-11T19:35:05Z

@copilot please address @jkotas feedback

All four items addressed in f497166.

Copilot · 2026-04-09T11:20:47Z

Description

Implements the ProcessStartInfo.KillOnParentExit property for Windows, which terminates child processes when the parent process exits. This is the Windows part of the KillOnParentExit feature.

API approved at #125838 (comment)

Changes Made

New API surface:

Added KillOnParentExit property to ProcessStartInfo with [SupportedOSPlatform("windows")] attribute (linux support will be added in upcoming PRs)
Added to reference assembly (ref/System.Diagnostics.Process.cs) with matching [SupportedOSPlatformAttribute("windows")]
Added XML documentation with a link to the Windows SDK description of JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE

Windows implementation (SafeProcessHandle.Windows.cs):

Added a lazily-initialized static SafeJobHandle with JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE flag, shared across all child processes with KillOnParentExit=true
For CreateProcess path (no user credentials): uses PROC_THREAD_ATTRIBUTE_JOB_LIST in the extended startup info for atomic job assignment at process creation
For CreateProcessWithLogonW path (with user credentials): starts the process suspended, assigns it to the job object via AssignProcessToJobObject, then resumes the thread only on the happy path — on failure, the suspended process is terminated
ResumeThread return value is checked; failure throws Win32Exception and the suspended process is terminated
AssignJobAndResumeThread takes (IntPtr hThread, SafeProcessHandle procSH) and uses procSH consistently for all process handle operations (no mixing of processInfo.hProcess and procSH)
ConfigureExtendedStartupInfo returns bool and the caller sets creationFlags, startupInfoEx.StartupInfo.cb, and startupInfoEx.lpAttributeList to reduce the number of method arguments
Uses string.IsNullOrEmpty(startInfo.UserName) for defensive checks when determining the code path

P/Invoke definitions:

Interop.JobObjects.cs: CreateJobObjectW, SetInformationJobObject, AssignProcessToJobObject (accepts SafeProcessHandle), JOBOBJECT_EXTENDED_LIMIT_INFORMATION, IO_COUNTERS, JOBOBJECTINFOCLASS structs/enums, SafeJobHandle, PROC_THREAD_ATTRIBUTE_JOB_LIST constant
Interop.ResumeThread.cs: ResumeThread P/Invoke returning uint (matching native DWORD) in its own dedicated file (following the pattern of Interop.TerminateProcess.cs, Interop.GetExitCodeProcess.cs, etc.)
IO_COUNTERS and JOBOBJECT_EXTENDED_LIMIT_INFORMATION use nuint for fields representing numerical values (sizes, limits, affinity masks) per interop convention
Replaced the local ResumeThread P/Invoke in ProcessHandlesTests.Windows.cs with the shared Interop.Kernel32.ResumeThread, eliminating the duplicate declaration and aligning the test code with the production uint/0xFFFFFFFF pattern

Validation:

Extended ProcessStartInfo.ThrowIfInvalid to throw InvalidOperationException when KillOnParentExit is combined with UseShellExecute
Added KillOnParentExitCannotBeUsedWithUseShellExecute string resource

Tests (KillOnParentExitTests.cs):

KillOnParentExit_DefaultsToFalse / KillOnParentExit_CanBeSetToTrue — property basics
KillOnParentExit_WithUseShellExecute_Throws — validation test
KillOnParentExit_ProcessStartsAndExitsNormally — smoke test
KillOnParentExit_KillsTheChild_WhenParentExits — verifies child is killed (enabled=true) or survives (enabled=false) on normal parent exit, reports grandchild pid via stdout
KillOnParentExit_KillsTheChild_WhenParentIsKilled — same when parent is forcefully killed
KillOnParentExit_KillsTheChild_WhenParentCrashes — same when parent crashes (access violation)
User credentials code path is exercised via the updated ProcessStartInfoTests.TestUserCredentialsPropertiesOnWindows (admin/OuterLoop)

Add KillOnParentExit property to ProcessStartInfo that terminates child processes when the parent process exits. Windows implementation uses Job Objects with JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE flag. For CreateProcess: uses PROC_THREAD_ATTRIBUTE_JOB_LIST for atomic assignment. For CreateProcessWithLogonW: starts suspended, assigns to job, then resumes. Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/61612ca1-930c-4836-8554-d143d05c8321 Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

adamsitnik

@copilot address my feedback

…py path, add user credentials test, fix pid reporting via stdout, remove nop UseShellExecute test Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/c4dd95b4-cd8e-4740-83f9-7358444c04ce Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

Copilot · 2026-04-09T12:51:22Z

@copilot address my feedback

All feedback addressed in 31f6e6b. All 403 tests pass.

- simplify the tests - avoid duplication!!

Copilot

Pull request overview

Implements Windows support for ProcessStartInfo.KillOnParentExit by using Windows Job Objects to ensure spawned processes are terminated when the parent exits.

Changes:

Added ProcessStartInfo.KillOnParentExit API surface (implementation + ref assembly) and validation against UseShellExecute.
Implemented Windows job-object based process start paths (CreateProcess job-list attribute, and CreateProcessWithLogonW suspended + assign + resume).
Added Windows-focused tests validating the behavior.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
src/libraries/System.Diagnostics.Process/tests/System.Diagnostics.Process.Tests.csproj	Includes the new KillOnParentExit test file in the test project.
src/libraries/System.Diagnostics.Process/tests/ProcessStartInfoTests.cs	Extends existing Windows credential tests to cover KillOnParentExit on that path.
src/libraries/System.Diagnostics.Process/tests/KillOnParentExitTests.cs	Adds new Windows tests validating KillOnParentExit behavior under various parent-exit scenarios.
src/libraries/System.Diagnostics.Process/src/System/Diagnostics/ProcessStartInfo.cs	Adds the KillOnParentExit property, docs, and validation with UseShellExecute.
src/libraries/System.Diagnostics.Process/src/System.Diagnostics.Process.csproj	Links in the new Windows job-object interop file.
src/libraries/System.Diagnostics.Process/src/Resources/Strings.resx	Adds a resource string for the KillOnParentExit + UseShellExecute validation.
src/libraries/System.Diagnostics.Process/src/Microsoft/Win32/SafeHandles/SafeProcessHandle.Windows.cs	Windows implementation: shared job handle, job-list attribute support, and logon path job assignment.
src/libraries/System.Diagnostics.Process/ref/System.Diagnostics.Process.cs	Adds the KillOnParentExit property to the reference assembly surface.
src/libraries/Common/src/Interop/Windows/Kernel32/Interop.JobObjects.cs	Adds required job-object P/Invokes/structs/constants.
src/libraries/Common/src/Interop/Windows/Advapi32/Interop.ProcessOptions.cs	Adds CREATE_SUSPENDED for the CreateProcessWithLogonW suspended-start path.

adamsitnik

@copilot address my feedback

…sumeThread return, remove unused using, improve VerifyProcessIsRunning polling Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/06c58cfa-bdef-4f35-9345-9ab03e7dc542 Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

Copilot · 2026-04-09T16:17:49Z

@copilot address my feedback

All feedback addressed in cc04598. Source builds and all 401 tests pass.

jkotas · 2026-04-11T14:10:07Z

ProcessHandlesTests.Windows.cs (line 187) has a local private static partial int ResumeThread(nint hThread) with == -1 check. This is technically correct (same bit pattern) but inconsistent with the production code's uint/0xFFFFFFFF pattern.

@copilot Address this feedback by replacing the local ResumeThread with the shared copy

…d Interop.Kernel32.ResumeThread Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/e8bb36bc-5c71-4723-a32c-17e87d762370 Co-authored-by: jkotas <6668460+jkotas@users.noreply.github.com>

Copilot · 2026-04-11T14:20:09Z

ProcessHandlesTests.Windows.cs (line 187) has a local private static partial int ResumeThread(nint hThread) with == -1 check. This is technically correct (same bit pattern) but inconsistent with the...

Replaced the local ResumeThread P/Invoke in ProcessHandlesTests.Windows.cs with the shared Interop.Kernel32.ResumeThread (returns uint, check == 0xFFFFFFFF) in c5b7d59. Also added the Interop.ResumeThread.cs reference to the test csproj.

…al ResumeThread P/Invoke Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/e8bb36bc-5c71-4723-a32c-17e87d762370 Co-authored-by: jkotas <6668460+jkotas@users.noreply.github.com>

Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/f3703368-dbc7-4226-8258-1bb793d93faf Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

adamsitnik · 2026-04-11T19:25:17Z

@copilot please address @jkotas feedback

…, unnecessary assert, reduce ConfigureExtendedStartupInfo args Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/2dd25b7c-da4a-4ed0-a9b3-cc6561f14aeb Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

Copilot · 2026-04-11T19:35:05Z

@copilot please address @jkotas feedback

All four items addressed in f497166.

Copilot · 2026-04-09T11:20:47Z

Description

Implements the ProcessStartInfo.KillOnParentExit property for Windows, which terminates child processes when the parent process exits. This is the Windows part of the KillOnParentExit feature.

API approved at #125838 (comment)

Changes Made

New API surface:

Added KillOnParentExit property to ProcessStartInfo with [SupportedOSPlatform("windows")] attribute (linux support will be added in upcoming PRs)
Added to reference assembly (ref/System.Diagnostics.Process.cs) with matching [SupportedOSPlatformAttribute("windows")]
Added XML documentation with a link to the Windows SDK description of JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE

Windows implementation (SafeProcessHandle.Windows.cs):

Added a lazily-initialized static SafeJobHandle with JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE flag, shared across all child processes with KillOnParentExit=true
For CreateProcess path (no user credentials): uses PROC_THREAD_ATTRIBUTE_JOB_LIST in the extended startup info for atomic job assignment at process creation
For CreateProcessWithLogonW path (with user credentials): starts the process suspended, assigns it to the job object via AssignProcessToJobObject, then resumes the thread only on the happy path — on failure, the suspended process is terminated
ResumeThread return value is checked; failure throws Win32Exception and the suspended process is terminated
AssignJobAndResumeThread takes (IntPtr hThread, SafeProcessHandle procSH) and uses procSH consistently for all process handle operations (no mixing of processInfo.hProcess and procSH)
ConfigureExtendedStartupInfo returns bool and the caller sets creationFlags, startupInfoEx.StartupInfo.cb, and startupInfoEx.lpAttributeList to reduce the number of method arguments
Uses string.IsNullOrEmpty(startInfo.UserName) for defensive checks when determining the code path

P/Invoke definitions:

Interop.JobObjects.cs: CreateJobObjectW, SetInformationJobObject, AssignProcessToJobObject (accepts SafeProcessHandle), JOBOBJECT_EXTENDED_LIMIT_INFORMATION, IO_COUNTERS, JOBOBJECTINFOCLASS structs/enums, SafeJobHandle, PROC_THREAD_ATTRIBUTE_JOB_LIST constant
Interop.ResumeThread.cs: ResumeThread P/Invoke returning uint (matching native DWORD) in its own dedicated file (following the pattern of Interop.TerminateProcess.cs, Interop.GetExitCodeProcess.cs, etc.)
IO_COUNTERS and JOBOBJECT_EXTENDED_LIMIT_INFORMATION use nuint for fields representing numerical values (sizes, limits, affinity masks) per interop convention
Replaced the local ResumeThread P/Invoke in ProcessHandlesTests.Windows.cs with the shared Interop.Kernel32.ResumeThread, eliminating the duplicate declaration and aligning the test code with the production uint/0xFFFFFFFF pattern

Validation:

Extended ProcessStartInfo.ThrowIfInvalid to throw InvalidOperationException when KillOnParentExit is combined with UseShellExecute
Added KillOnParentExitCannotBeUsedWithUseShellExecute string resource

Tests (KillOnParentExitTests.cs):

KillOnParentExit_DefaultsToFalse / KillOnParentExit_CanBeSetToTrue — property basics
KillOnParentExit_WithUseShellExecute_Throws — validation test
KillOnParentExit_ProcessStartsAndExitsNormally — smoke test
KillOnParentExit_KillsTheChild_WhenParentExits — verifies child is killed (enabled=true) or survives (enabled=false) on normal parent exit, reports grandchild pid via stdout
KillOnParentExit_KillsTheChild_WhenParentIsKilled — same when parent is forcefully killed
KillOnParentExit_KillsTheChild_WhenParentCrashes — same when parent crashes (access violation)
User credentials code path is exercised via the updated ProcessStartInfoTests.TestUserCredentialsPropertiesOnWindows (admin/OuterLoop)

Add KillOnParentExit property to ProcessStartInfo that terminates child processes when the parent process exits. Windows implementation uses Job Objects with JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE flag. For CreateProcess: uses PROC_THREAD_ATTRIBUTE_JOB_LIST for atomic assignment. For CreateProcessWithLogonW: starts suspended, assigns to job, then resumes. Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/61612ca1-930c-4836-8554-d143d05c8321 Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

adamsitnik

@copilot address my feedback

…py path, add user credentials test, fix pid reporting via stdout, remove nop UseShellExecute test Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/c4dd95b4-cd8e-4740-83f9-7358444c04ce Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

Copilot · 2026-04-09T12:51:22Z

@copilot address my feedback

All feedback addressed in 31f6e6b. All 403 tests pass.

- simplify the tests - avoid duplication!!

Copilot

Pull request overview

Implements Windows support for ProcessStartInfo.KillOnParentExit by using Windows Job Objects to ensure spawned processes are terminated when the parent exits.

Changes:

Added ProcessStartInfo.KillOnParentExit API surface (implementation + ref assembly) and validation against UseShellExecute.
Implemented Windows job-object based process start paths (CreateProcess job-list attribute, and CreateProcessWithLogonW suspended + assign + resume).
Added Windows-focused tests validating the behavior.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
src/libraries/System.Diagnostics.Process/tests/System.Diagnostics.Process.Tests.csproj	Includes the new KillOnParentExit test file in the test project.
src/libraries/System.Diagnostics.Process/tests/ProcessStartInfoTests.cs	Extends existing Windows credential tests to cover KillOnParentExit on that path.
src/libraries/System.Diagnostics.Process/tests/KillOnParentExitTests.cs	Adds new Windows tests validating KillOnParentExit behavior under various parent-exit scenarios.
src/libraries/System.Diagnostics.Process/src/System/Diagnostics/ProcessStartInfo.cs	Adds the KillOnParentExit property, docs, and validation with UseShellExecute.
src/libraries/System.Diagnostics.Process/src/System.Diagnostics.Process.csproj	Links in the new Windows job-object interop file.
src/libraries/System.Diagnostics.Process/src/Resources/Strings.resx	Adds a resource string for the KillOnParentExit + UseShellExecute validation.
src/libraries/System.Diagnostics.Process/src/Microsoft/Win32/SafeHandles/SafeProcessHandle.Windows.cs	Windows implementation: shared job handle, job-list attribute support, and logon path job assignment.
src/libraries/System.Diagnostics.Process/ref/System.Diagnostics.Process.cs	Adds the KillOnParentExit property to the reference assembly surface.
src/libraries/Common/src/Interop/Windows/Kernel32/Interop.JobObjects.cs	Adds required job-object P/Invokes/structs/constants.
src/libraries/Common/src/Interop/Windows/Advapi32/Interop.ProcessOptions.cs	Adds CREATE_SUSPENDED for the CreateProcessWithLogonW suspended-start path.

adamsitnik

@copilot address my feedback

…sumeThread return, remove unused using, improve VerifyProcessIsRunning polling Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/06c58cfa-bdef-4f35-9345-9ab03e7dc542 Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

Copilot · 2026-04-09T16:17:49Z

@copilot address my feedback

All feedback addressed in cc04598. Source builds and all 401 tests pass.

jkotas · 2026-04-11T14:10:07Z

ProcessHandlesTests.Windows.cs (line 187) has a local private static partial int ResumeThread(nint hThread) with == -1 check. This is technically correct (same bit pattern) but inconsistent with the production code's uint/0xFFFFFFFF pattern.

@copilot Address this feedback by replacing the local ResumeThread with the shared copy

…d Interop.Kernel32.ResumeThread Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/e8bb36bc-5c71-4723-a32c-17e87d762370 Co-authored-by: jkotas <6668460+jkotas@users.noreply.github.com>

Copilot · 2026-04-11T14:20:09Z

ProcessHandlesTests.Windows.cs (line 187) has a local private static partial int ResumeThread(nint hThread) with == -1 check. This is technically correct (same bit pattern) but inconsistent with the...

Replaced the local ResumeThread P/Invoke in ProcessHandlesTests.Windows.cs with the shared Interop.Kernel32.ResumeThread (returns uint, check == 0xFFFFFFFF) in c5b7d59. Also added the Interop.ResumeThread.cs reference to the test csproj.

…al ResumeThread P/Invoke Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/e8bb36bc-5c71-4723-a32c-17e87d762370 Co-authored-by: jkotas <6668460+jkotas@users.noreply.github.com>

Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/f3703368-dbc7-4226-8258-1bb793d93faf Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

adamsitnik · 2026-04-11T19:25:17Z

@copilot please address @jkotas feedback

…, unnecessary assert, reduce ConfigureExtendedStartupInfo args Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/2dd25b7c-da4a-4ed0-a9b3-cc6561f14aeb Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

Copilot · 2026-04-11T19:35:05Z

@copilot please address @jkotas feedback

All four items addressed in f497166.

Copilot · 2026-04-09T11:20:47Z

Description

Implements the ProcessStartInfo.KillOnParentExit property for Windows, which terminates child processes when the parent process exits. This is the Windows part of the KillOnParentExit feature.

API approved at #125838 (comment)

Changes Made

New API surface:

Added KillOnParentExit property to ProcessStartInfo with [SupportedOSPlatform("windows")] attribute (linux support will be added in upcoming PRs)
Added to reference assembly (ref/System.Diagnostics.Process.cs) with matching [SupportedOSPlatformAttribute("windows")]
Added XML documentation with a link to the Windows SDK description of JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE

Windows implementation (SafeProcessHandle.Windows.cs):

Added a lazily-initialized static SafeJobHandle with JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE flag, shared across all child processes with KillOnParentExit=true
For CreateProcess path (no user credentials): uses PROC_THREAD_ATTRIBUTE_JOB_LIST in the extended startup info for atomic job assignment at process creation
For CreateProcessWithLogonW path (with user credentials): starts the process suspended, assigns it to the job object via AssignProcessToJobObject, then resumes the thread only on the happy path — on failure, the suspended process is terminated
ResumeThread return value is checked; failure throws Win32Exception and the suspended process is terminated
AssignJobAndResumeThread takes (IntPtr hThread, SafeProcessHandle procSH) and uses procSH consistently for all process handle operations (no mixing of processInfo.hProcess and procSH)
ConfigureExtendedStartupInfo returns bool and the caller sets creationFlags, startupInfoEx.StartupInfo.cb, and startupInfoEx.lpAttributeList to reduce the number of method arguments
Uses string.IsNullOrEmpty(startInfo.UserName) for defensive checks when determining the code path

P/Invoke definitions:

Interop.JobObjects.cs: CreateJobObjectW, SetInformationJobObject, AssignProcessToJobObject (accepts SafeProcessHandle), JOBOBJECT_EXTENDED_LIMIT_INFORMATION, IO_COUNTERS, JOBOBJECTINFOCLASS structs/enums, SafeJobHandle, PROC_THREAD_ATTRIBUTE_JOB_LIST constant
Interop.ResumeThread.cs: ResumeThread P/Invoke returning uint (matching native DWORD) in its own dedicated file (following the pattern of Interop.TerminateProcess.cs, Interop.GetExitCodeProcess.cs, etc.)
IO_COUNTERS and JOBOBJECT_EXTENDED_LIMIT_INFORMATION use nuint for fields representing numerical values (sizes, limits, affinity masks) per interop convention
Replaced the local ResumeThread P/Invoke in ProcessHandlesTests.Windows.cs with the shared Interop.Kernel32.ResumeThread, eliminating the duplicate declaration and aligning the test code with the production uint/0xFFFFFFFF pattern

Validation:

Extended ProcessStartInfo.ThrowIfInvalid to throw InvalidOperationException when KillOnParentExit is combined with UseShellExecute
Added KillOnParentExitCannotBeUsedWithUseShellExecute string resource

Tests (KillOnParentExitTests.cs):

KillOnParentExit_DefaultsToFalse / KillOnParentExit_CanBeSetToTrue — property basics
KillOnParentExit_WithUseShellExecute_Throws — validation test
KillOnParentExit_ProcessStartsAndExitsNormally — smoke test
KillOnParentExit_KillsTheChild_WhenParentExits — verifies child is killed (enabled=true) or survives (enabled=false) on normal parent exit, reports grandchild pid via stdout
KillOnParentExit_KillsTheChild_WhenParentIsKilled — same when parent is forcefully killed
KillOnParentExit_KillsTheChild_WhenParentCrashes — same when parent crashes (access violation)
User credentials code path is exercised via the updated ProcessStartInfoTests.TestUserCredentialsPropertiesOnWindows (admin/OuterLoop)

Add KillOnParentExit property to ProcessStartInfo that terminates child processes when the parent process exits. Windows implementation uses Job Objects with JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE flag. For CreateProcess: uses PROC_THREAD_ATTRIBUTE_JOB_LIST for atomic assignment. For CreateProcessWithLogonW: starts suspended, assigns to job, then resumes. Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/61612ca1-930c-4836-8554-d143d05c8321 Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

adamsitnik

@copilot address my feedback

…py path, add user credentials test, fix pid reporting via stdout, remove nop UseShellExecute test Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/c4dd95b4-cd8e-4740-83f9-7358444c04ce Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

Copilot · 2026-04-09T12:51:22Z

@copilot address my feedback

All feedback addressed in 31f6e6b. All 403 tests pass.

- simplify the tests - avoid duplication!!

Copilot

Pull request overview

Implements Windows support for ProcessStartInfo.KillOnParentExit by using Windows Job Objects to ensure spawned processes are terminated when the parent exits.

Changes:

Added ProcessStartInfo.KillOnParentExit API surface (implementation + ref assembly) and validation against UseShellExecute.
Implemented Windows job-object based process start paths (CreateProcess job-list attribute, and CreateProcessWithLogonW suspended + assign + resume).
Added Windows-focused tests validating the behavior.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
src/libraries/System.Diagnostics.Process/tests/System.Diagnostics.Process.Tests.csproj	Includes the new KillOnParentExit test file in the test project.
src/libraries/System.Diagnostics.Process/tests/ProcessStartInfoTests.cs	Extends existing Windows credential tests to cover KillOnParentExit on that path.
src/libraries/System.Diagnostics.Process/tests/KillOnParentExitTests.cs	Adds new Windows tests validating KillOnParentExit behavior under various parent-exit scenarios.
src/libraries/System.Diagnostics.Process/src/System/Diagnostics/ProcessStartInfo.cs	Adds the KillOnParentExit property, docs, and validation with UseShellExecute.
src/libraries/System.Diagnostics.Process/src/System.Diagnostics.Process.csproj	Links in the new Windows job-object interop file.
src/libraries/System.Diagnostics.Process/src/Resources/Strings.resx	Adds a resource string for the KillOnParentExit + UseShellExecute validation.
src/libraries/System.Diagnostics.Process/src/Microsoft/Win32/SafeHandles/SafeProcessHandle.Windows.cs	Windows implementation: shared job handle, job-list attribute support, and logon path job assignment.
src/libraries/System.Diagnostics.Process/ref/System.Diagnostics.Process.cs	Adds the KillOnParentExit property to the reference assembly surface.
src/libraries/Common/src/Interop/Windows/Kernel32/Interop.JobObjects.cs	Adds required job-object P/Invokes/structs/constants.
src/libraries/Common/src/Interop/Windows/Advapi32/Interop.ProcessOptions.cs	Adds CREATE_SUSPENDED for the CreateProcessWithLogonW suspended-start path.

adamsitnik

@copilot address my feedback

…sumeThread return, remove unused using, improve VerifyProcessIsRunning polling Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/06c58cfa-bdef-4f35-9345-9ab03e7dc542 Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

Copilot · 2026-04-09T16:17:49Z

@copilot address my feedback

All feedback addressed in cc04598. Source builds and all 401 tests pass.

jkotas · 2026-04-11T14:10:07Z

ProcessHandlesTests.Windows.cs (line 187) has a local private static partial int ResumeThread(nint hThread) with == -1 check. This is technically correct (same bit pattern) but inconsistent with the production code's uint/0xFFFFFFFF pattern.

@copilot Address this feedback by replacing the local ResumeThread with the shared copy

…d Interop.Kernel32.ResumeThread Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/e8bb36bc-5c71-4723-a32c-17e87d762370 Co-authored-by: jkotas <6668460+jkotas@users.noreply.github.com>

Copilot · 2026-04-11T14:20:09Z

ProcessHandlesTests.Windows.cs (line 187) has a local private static partial int ResumeThread(nint hThread) with == -1 check. This is technically correct (same bit pattern) but inconsistent with the...

Replaced the local ResumeThread P/Invoke in ProcessHandlesTests.Windows.cs with the shared Interop.Kernel32.ResumeThread (returns uint, check == 0xFFFFFFFF) in c5b7d59. Also added the Interop.ResumeThread.cs reference to the test csproj.

…al ResumeThread P/Invoke Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/e8bb36bc-5c71-4723-a32c-17e87d762370 Co-authored-by: jkotas <6668460+jkotas@users.noreply.github.com>

Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/f3703368-dbc7-4226-8258-1bb793d93faf Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

adamsitnik · 2026-04-11T19:25:17Z

@copilot please address @jkotas feedback

…, unnecessary assert, reduce ConfigureExtendedStartupInfo args Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/2dd25b7c-da4a-4ed0-a9b3-cc6561f14aeb Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

Copilot · 2026-04-11T19:35:05Z

@copilot please address @jkotas feedback

All four items addressed in f497166.

Copilot · 2026-04-09T11:20:47Z

Description

Implements the ProcessStartInfo.KillOnParentExit property for Windows, which terminates child processes when the parent process exits. This is the Windows part of the KillOnParentExit feature.

API approved at #125838 (comment)

Changes Made

New API surface:

Added KillOnParentExit property to ProcessStartInfo with [SupportedOSPlatform("windows")] attribute (linux support will be added in upcoming PRs)
Added to reference assembly (ref/System.Diagnostics.Process.cs) with matching [SupportedOSPlatformAttribute("windows")]
Added XML documentation with a link to the Windows SDK description of JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE

Windows implementation (SafeProcessHandle.Windows.cs):

Added a lazily-initialized static SafeJobHandle with JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE flag, shared across all child processes with KillOnParentExit=true
For CreateProcess path (no user credentials): uses PROC_THREAD_ATTRIBUTE_JOB_LIST in the extended startup info for atomic job assignment at process creation
For CreateProcessWithLogonW path (with user credentials): starts the process suspended, assigns it to the job object via AssignProcessToJobObject, then resumes the thread only on the happy path — on failure, the suspended process is terminated
ResumeThread return value is checked; failure throws Win32Exception and the suspended process is terminated
AssignJobAndResumeThread takes (IntPtr hThread, SafeProcessHandle procSH) and uses procSH consistently for all process handle operations (no mixing of processInfo.hProcess and procSH)
ConfigureExtendedStartupInfo returns bool and the caller sets creationFlags, startupInfoEx.StartupInfo.cb, and startupInfoEx.lpAttributeList to reduce the number of method arguments
Uses string.IsNullOrEmpty(startInfo.UserName) for defensive checks when determining the code path

P/Invoke definitions:

Interop.JobObjects.cs: CreateJobObjectW, SetInformationJobObject, AssignProcessToJobObject (accepts SafeProcessHandle), JOBOBJECT_EXTENDED_LIMIT_INFORMATION, IO_COUNTERS, JOBOBJECTINFOCLASS structs/enums, SafeJobHandle, PROC_THREAD_ATTRIBUTE_JOB_LIST constant
Interop.ResumeThread.cs: ResumeThread P/Invoke returning uint (matching native DWORD) in its own dedicated file (following the pattern of Interop.TerminateProcess.cs, Interop.GetExitCodeProcess.cs, etc.)
IO_COUNTERS and JOBOBJECT_EXTENDED_LIMIT_INFORMATION use nuint for fields representing numerical values (sizes, limits, affinity masks) per interop convention
Replaced the local ResumeThread P/Invoke in ProcessHandlesTests.Windows.cs with the shared Interop.Kernel32.ResumeThread, eliminating the duplicate declaration and aligning the test code with the production uint/0xFFFFFFFF pattern

Validation:

Extended ProcessStartInfo.ThrowIfInvalid to throw InvalidOperationException when KillOnParentExit is combined with UseShellExecute
Added KillOnParentExitCannotBeUsedWithUseShellExecute string resource

Tests (KillOnParentExitTests.cs):

KillOnParentExit_DefaultsToFalse / KillOnParentExit_CanBeSetToTrue — property basics
KillOnParentExit_WithUseShellExecute_Throws — validation test
KillOnParentExit_ProcessStartsAndExitsNormally — smoke test
KillOnParentExit_KillsTheChild_WhenParentExits — verifies child is killed (enabled=true) or survives (enabled=false) on normal parent exit, reports grandchild pid via stdout
KillOnParentExit_KillsTheChild_WhenParentIsKilled — same when parent is forcefully killed
KillOnParentExit_KillsTheChild_WhenParentCrashes — same when parent crashes (access violation)
User credentials code path is exercised via the updated ProcessStartInfoTests.TestUserCredentialsPropertiesOnWindows (admin/OuterLoop)

Add KillOnParentExit property to ProcessStartInfo that terminates child processes when the parent process exits. Windows implementation uses Job Objects with JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE flag. For CreateProcess: uses PROC_THREAD_ATTRIBUTE_JOB_LIST for atomic assignment. For CreateProcessWithLogonW: starts suspended, assigns to job, then resumes. Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/61612ca1-930c-4836-8554-d143d05c8321 Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

adamsitnik

@copilot address my feedback

…py path, add user credentials test, fix pid reporting via stdout, remove nop UseShellExecute test Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/c4dd95b4-cd8e-4740-83f9-7358444c04ce Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

Copilot · 2026-04-09T12:51:22Z

@copilot address my feedback

All feedback addressed in 31f6e6b. All 403 tests pass.

- simplify the tests - avoid duplication!!

Copilot

Pull request overview

Implements Windows support for ProcessStartInfo.KillOnParentExit by using Windows Job Objects to ensure spawned processes are terminated when the parent exits.

Changes:

Added ProcessStartInfo.KillOnParentExit API surface (implementation + ref assembly) and validation against UseShellExecute.
Implemented Windows job-object based process start paths (CreateProcess job-list attribute, and CreateProcessWithLogonW suspended + assign + resume).
Added Windows-focused tests validating the behavior.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
src/libraries/System.Diagnostics.Process/tests/System.Diagnostics.Process.Tests.csproj	Includes the new KillOnParentExit test file in the test project.
src/libraries/System.Diagnostics.Process/tests/ProcessStartInfoTests.cs	Extends existing Windows credential tests to cover KillOnParentExit on that path.
src/libraries/System.Diagnostics.Process/tests/KillOnParentExitTests.cs	Adds new Windows tests validating KillOnParentExit behavior under various parent-exit scenarios.
src/libraries/System.Diagnostics.Process/src/System/Diagnostics/ProcessStartInfo.cs	Adds the KillOnParentExit property, docs, and validation with UseShellExecute.
src/libraries/System.Diagnostics.Process/src/System.Diagnostics.Process.csproj	Links in the new Windows job-object interop file.
src/libraries/System.Diagnostics.Process/src/Resources/Strings.resx	Adds a resource string for the KillOnParentExit + UseShellExecute validation.
src/libraries/System.Diagnostics.Process/src/Microsoft/Win32/SafeHandles/SafeProcessHandle.Windows.cs	Windows implementation: shared job handle, job-list attribute support, and logon path job assignment.
src/libraries/System.Diagnostics.Process/ref/System.Diagnostics.Process.cs	Adds the KillOnParentExit property to the reference assembly surface.
src/libraries/Common/src/Interop/Windows/Kernel32/Interop.JobObjects.cs	Adds required job-object P/Invokes/structs/constants.
src/libraries/Common/src/Interop/Windows/Advapi32/Interop.ProcessOptions.cs	Adds CREATE_SUSPENDED for the CreateProcessWithLogonW suspended-start path.

adamsitnik

@copilot address my feedback

…sumeThread return, remove unused using, improve VerifyProcessIsRunning polling Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/06c58cfa-bdef-4f35-9345-9ab03e7dc542 Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

Copilot · 2026-04-09T16:17:49Z

@copilot address my feedback

All feedback addressed in cc04598. Source builds and all 401 tests pass.

jkotas · 2026-04-11T14:10:07Z

ProcessHandlesTests.Windows.cs (line 187) has a local private static partial int ResumeThread(nint hThread) with == -1 check. This is technically correct (same bit pattern) but inconsistent with the production code's uint/0xFFFFFFFF pattern.

@copilot Address this feedback by replacing the local ResumeThread with the shared copy

…d Interop.Kernel32.ResumeThread Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/e8bb36bc-5c71-4723-a32c-17e87d762370 Co-authored-by: jkotas <6668460+jkotas@users.noreply.github.com>

Copilot · 2026-04-11T14:20:09Z

ProcessHandlesTests.Windows.cs (line 187) has a local private static partial int ResumeThread(nint hThread) with == -1 check. This is technically correct (same bit pattern) but inconsistent with the...

Replaced the local ResumeThread P/Invoke in ProcessHandlesTests.Windows.cs with the shared Interop.Kernel32.ResumeThread (returns uint, check == 0xFFFFFFFF) in c5b7d59. Also added the Interop.ResumeThread.cs reference to the test csproj.

…al ResumeThread P/Invoke Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/e8bb36bc-5c71-4723-a32c-17e87d762370 Co-authored-by: jkotas <6668460+jkotas@users.noreply.github.com>

Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/f3703368-dbc7-4226-8258-1bb793d93faf Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

adamsitnik · 2026-04-11T19:25:17Z

@copilot please address @jkotas feedback

…, unnecessary assert, reduce ConfigureExtendedStartupInfo args Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/2dd25b7c-da4a-4ed0-a9b3-cc6561f14aeb Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

Copilot · 2026-04-11T19:35:05Z

@copilot please address @jkotas feedback

All four items addressed in f497166.

CopilotAI assigned Copilot and adamsitnik Apr 9, 2026

CopilotAI requested review from Copilot and removed request for Copilot April 9, 2026 11:20

Copilotcreated this pull request from a session on behalf of adamsitnik April 9, 2026 11:20 View session

github-actionsBot added the area-System.Diagnostics.Process label Apr 9, 2026

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adamsitnik added this to the 11.0.0 milestone Apr 9, 2026

adamsitnik added the NO-REVIEW Experimental/testing PR, do NOT review it label Apr 9, 2026

CopilotAI requested review from Copilot and removed request for Copilot April 9, 2026 12:50

CopilotAI changed the title ~~Implementing KillOnParentExit property in ProcessStartInfo class~~Implement ProcessStartInfo.KillOnParentExit for WindowsApr 9, 2026

Copilotfinished work on behalf of adamsitnik April 9, 2026 12:53

CopilotAI requested a review from adamsitnik April 9, 2026 12:53

address my own feedback:
b910623
- simplify the tests - avoid duplication!!

CopilotAI review requested due to automatic review settings April 9, 2026 14:13

adamsitnik marked this pull request as ready for review April 9, 2026 14:20

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Comment threadsrc/libraries/System.Diagnostics.Process/src/System/Diagnostics/ProcessStartInfo.cs

jkotas mentioned this pull request Apr 11, 2026
System.Runtime.InteropServices.Tests.DestroyStructureTests.DestroyStructure_Blittable_Success failing in CI #126788
Closed

Copilotstarted work on behalf of jkotas April 11, 2026 14:10 View session

Replace local ResumeThread P/Invoke in ProcessHandlesTests with share…
c5b7d59
…d Interop.Kernel32.ResumeThread Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/e8bb36bc-5c71-4723-a32c-17e87d762370 Co-authored-by: jkotas <6668460+jkotas@users.noreply.github.com>

Remove unused System.Runtime.InteropServices using after removing loc…
84ca617
…al ResumeThread P/Invoke Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/e8bb36bc-5c71-4723-a32c-17e87d762370 Co-authored-by: jkotas <6668460+jkotas@users.noreply.github.com>

CopilotAI requested review from Copilot and removed request for Copilot April 11, 2026 14:21

Copilotfinished work on behalf of jkotas April 11, 2026 14:22

CopilotAI mentioned this pull request Apr 11, 2026
Fix WasmTestOnChrome: exclude browser/wasi from gen-debug-dump-docs.py helix post-command #126789
Merged
1 task

Copilotstarted work on behalf of adamsitnik April 11, 2026 17:12 View session

Remove defensive HELIX_WORKITEM_UPLOAD_ROOT env var from crash test
96e2804
Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/f3703368-dbc7-4226-8258-1bb793d93faf Co-authored-by: adamsitnik <6011991+adamsitnik@users.noreply.github.com>

CopilotAI requested review from Copilot and removed request for Copilot April 11, 2026 17:16

Copilotfinished work on behalf of adamsitnik April 11, 2026 17:18

jkotas approved these changes Apr 11, 2026
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Copilotfinished work on behalf of adamsitnik April 11, 2026 19:36

adamsitnik enabled auto-merge (squash) April 11, 2026 19:41

CopilotAI mentioned this pull request Apr 11, 2026
Fix NullReferenceException in DestroyStructure for blittable types #126795
Merged

This was referenced Apr 11, 2026
Unable to pull image from mcr.microsoft.com #117164
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AF: *(_UNCHECKED_OBJECTREF *)handle == NULL (HndCreateHandle called by getJitHandleForObject) #117138
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dotnet-maestroBot mentioned this pull request Apr 15, 2026
[main] Source code updates from dotnet/runtime dotnet/dotnet#6035
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[API Proposal]: Kill System.Diagnostics.Process on parent death #101985
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Take advantage of the new Process APIs dotnet/sdk#53916
Open