Support unseekable filestream when ReadAllBytes[Async]

[lateapexearlyspeed]

…dAllBytes[Async].

Fix#58383 , will update PR status when it is ready for review.

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Issue Details

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…dAllBytes[Async].

Fix #58383 , will update PR status when it is ready for review.

Author:	lateapexearlyspeed
Assignees:	-
Labels:	area-System.IO
Milestone:	-

[am11]

It looks like there is some difference in how character devices are treated in .NET 5 vs. .NET 6.

e.g. this simple console program:

usingSystem;usingSystem.IO;usingSystem.Threading;usingSystem.Threading.Tasks;//using Xunit;FileTestsfileTests=new();awaitfileTests.ReadAllBytes_NonSeekableFileStream_InUnix();Console.WriteLine("Passed!");publicclassFileTests{// [Fact]publicasyncTaskReadAllBytes_NonSeekableFileStream_InUnix(){varpath="/dev/tty";if(!File.Exists(path)){thrownewException(path+" is not available in this environment.");}varcontentBytes=newbyte[]{1,2,3};using(varcts=newCancellationTokenSource()){TaskwritingTask=File.WriteAllBytesAsync(path,contentBytes,cts.Token);cts.CancelAfter(TimeSpan.FromMilliseconds(500));awaitwritingTask;}}}

prints Passed! in .NET 5 on macOS, but with .NET 6 it throws Unhandled exception. System.IO.IOException: Device not configured : '/dev/tty'.

@tmds, @stephentoub, is this a known breaking change?

[stephentoub]

is this a known breaking change?

Not to my knowledge.
cc: @jeffhandley, @adamsitnik.

[tmds]

prints Passed! in .NET 5 on macOS, but with .NET 6 it throws Unhandled exception. System.IO.IOException: Device not configured : '/dev/tty'.

On Linux, it prints Passed! with rc1.

From the CI stack trace it looks like the open call fails. Running the macOS equivalent of strace may reveal the difference between .NET 5 and .NET 6.

@am11 can you create an issue for this?

[am11]

On Linux, it prints Passed! with rc1.

I can confirm that it's macOS-only regression in .NET 6.

@am11 can you create an issue for this?

#59754

[adamsitnik]

LGTM, big thanks for your contribution @lateapexearlyspeed !

[adamsitnik]

/backport to release/6.0

[github-actions]

Started backporting to release/6.0: https://github.com/dotnet/runtime/actions/runs/1412920156

[github-actions]

@adamsitnik backporting to release/6.0 failed, the patch most likely resulted in conflicts:

$ git am --3way --ignore-whitespace --keep-non-patch changes.patch
Applying: lateapexearlyspeed-issue-58383 Support unseekable filestream when ReadAllBytes[Async].
Applying: issue-58383 Refine code; Add test cases.
Applying: the docs were wrong, offsets are not ignored for non-seekable files
Using index info to reconstruct a base tree...
M	src/libraries/System.Private.CoreLib/src/System/IO/RandomAccess.Windows.cs
Falling back to patching base and 3-way merge...
Auto-merging src/libraries/System.Private.CoreLib/src/System/IO/RandomAccess.Windows.cs
CONFLICT (content): Merge conflict in src/libraries/System.Private.CoreLib/src/System/IO/RandomAccess.Windows.cs
error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
Patch failed at 0003 the docs were wrong, offsets are not ignored for non-seekable files
When you have resolved this problem, run "git am --continue".
If you prefer to skip this patch, run "git am --skip" instead.
To restore the original branch and stop patching, run "git am --abort".
Error: The process '/usr/bin/git' failed with exit code 128

Please backport manually!