Allow IPC named pipe directory to be overridden on Unix by Evangelink · Pull Request #9846 · microsoft/testfx

Evangelink · 2026-07-11T12:08:34Z

Problem

On Unix, the Microsoft.Testing.Platform IPC named pipe is backed by a Unix domain socket file on disk, and NamedPipeServer.GetPipeName hardcoded that file to live under /tmp. In sandboxed environments that block /tmp (the reporter hit this with Claude Code on macOS), dotnet test fails and the only workaround is to open up the whole /tmp folder to the sandbox.

Change

On Unix, the pipe directory is now resolved with this precedence:

TESTINGPLATFORM_PIPE_DIRECTORY — new explicit opt-in override (guaranteed escape hatch).
Path.GetTempPath() — honors TMPDIR on Unix, which is the standard POSIX knob and is usually a per-user, sandbox-allowed directory (so many setups are fixed with no extra configuration).
/tmp — preserves the previous default when neither is set.

Windows is unchanged (it uses the kernel pipe namespace, not the filesystem).

Guards

Because the location is now user-influenced:

Path length (always): Unix domain socket paths are capped by sun_path (~104 bytes on macOS, ~108 on Linux). We validate against the smaller 103-byte budget and fail with an actionable, localized message. This matters most for a deep TMPDIR on macOS (/var/folders/…/T/ + a GUID).
Writability (override only): when the explicit override is used we create the directory if needed and probe write access with a short-lived file, failing fast with a clear message instead of a cryptic socket bind error. TMPDIR//tmp are OS-managed and skipped to avoid extra I/O and a behavior change on every pipe creation.

Compatibility notes

The design deliberately keeps the existing invariant: the process that creates the pipe resolves the directory locally and hands the fully-resolved path to the peer (via env var, command-line arg, or the dotnet-test handshake); peers use that path verbatim and never recompute it. As a result:

No protocol version bump is needed — a TESTINGPLATFORM_PIPE_DIRECTORY/TMPDIR difference between two processes is harmless because only the creator's resolution is ever used.
The logic is self-contained in NamedPipeServer.cs, which dotnet/sdk vendors, so the dotnet test entrypoint picks this up on the next vendor sync with no separate SDK design work.

An XML-doc note on GetPipeName captures this invariant so the directory is never turned into a shared convention that both sides derive independently (which would couple SDK and test-host versions).

Localization

Two new strings added to PlatformResources.resx with hand-maintained accessors in the !IS_CORE_MTP block; .xlf regenerated for all 14 languages via UpdateXlf.

Tests

Added 8 MSTest cases in IPCTests.cs covering override precedence, TMPDIR fallback, /tmp fallback, and the length guard (within/exceeds). Resolution and length-check logic was split into internal seams so they are testable on Windows CI, where the Unix branch of GetPipeName never runs. Full IPCTests class passes locally (net8.0).

On Unix the IPC named pipe is backed by a Unix domain socket file that was always created under /tmp. Sandboxed environments (e.g. Claude Code on macOS) that block /tmp cannot run `dotnet test`. Resolve the directory as: 1. TESTINGPLATFORM_PIPE_DIRECTORY (explicit opt-in override) 2. Path.GetTempPath() (honors TMPDIR on Unix) 3. /tmp (previous default) Add a sun_path length guard (always) and a writability probe (override only), both failing with actionable, localized messages. Keep the logic self-contained in NamedPipeServer.cs so it flows into dotnet/sdk on the next vendor sync, and document the "creator resolves, full path is passed, peers never recompute" invariant so the directory never becomes a shared convention that couples SDK and test-host versions. Fixes #9821 Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: ae434eba-3cad-4c61-a1da-ef252ae87f48

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Pull request overview

Adds configurable Unix IPC socket directories for sandbox compatibility while preserving Windows behavior.

Changes:

Adds override/temp-directory resolution and safety guards.
Adds localized diagnostics and environment-variable support.
Adds unit tests and regenerated localization files.

Show a summary per file

File	Description
`test/UnitTests/Microsoft.Testing.Platform.UnitTests/IPC/IPCTests.cs`	Tests directory resolution and path-length limits.
`src/Platform/Microsoft.Testing.Platform/IPC/NamedPipeServer.cs`	Implements Unix pipe-directory selection and validation.
`src/Platform/Microsoft.Testing.Platform/Helpers/EnvironmentVariableConstants.cs`	Defines the pipe-directory override variable.
`src/Platform/Microsoft.Testing.Platform/Resources/PlatformResources.cs`	Adds resource accessors.
`src/Platform/Microsoft.Testing.Platform/Resources/PlatformResources.resx`	Adds localized diagnostic source strings.
`src/Platform/Microsoft.Testing.Platform/Resources/xlf/PlatformResources.cs.xlf`	Updates Czech localization.
`src/Platform/Microsoft.Testing.Platform/Resources/xlf/PlatformResources.de.xlf`	Updates German localization.
`src/Platform/Microsoft.Testing.Platform/Resources/xlf/PlatformResources.es.xlf`	Updates Spanish localization.
`src/Platform/Microsoft.Testing.Platform/Resources/xlf/PlatformResources.fr.xlf`	Updates French localization.
`src/Platform/Microsoft.Testing.Platform/Resources/xlf/PlatformResources.it.xlf`	Updates Italian localization.
`src/Platform/Microsoft.Testing.Platform/Resources/xlf/PlatformResources.ja.xlf`	Updates Japanese localization.
`src/Platform/Microsoft.Testing.Platform/Resources/xlf/PlatformResources.ko.xlf`	Updates Korean localization.
`src/Platform/Microsoft.Testing.Platform/Resources/xlf/PlatformResources.pl.xlf`	Updates Polish localization.
`src/Platform/Microsoft.Testing.Platform/Resources/xlf/PlatformResources.pt-BR.xlf`	Updates Brazilian Portuguese localization.
`src/Platform/Microsoft.Testing.Platform/Resources/xlf/PlatformResources.ru.xlf`	Updates Russian localization.
`src/Platform/Microsoft.Testing.Platform/Resources/xlf/PlatformResources.tr.xlf`	Updates Turkish localization.
`src/Platform/Microsoft.Testing.Platform/Resources/xlf/PlatformResources.zh-Hans.xlf`	Updates Simplified Chinese localization.
`src/Platform/Microsoft.Testing.Platform/Resources/xlf/PlatformResources.zh-Hant.xlf`	Updates Traditional Chinese localization.

Review details

Files reviewed: 18/18 changed files
Comments generated: 6
Review effort level: Medium

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Review Summary

Overall: Solid, well-motivated change. The design is sound — the single-resolver invariant (creator resolves, peer uses verbatim) is the right architecture and the XML doc captures it well. The guards (path length + writability probe) are practical and the error messages are actionable.

Findings by severity

Severity	Dimension	Finding
MAJOR	Test Completeness (#13)	`EnsureDirectoryIsWritable` has no unit tests — it has meaningful branching worth covering
MODERATE	Data-Driven (#14)	Missing `" "` (whitespace) `[DataRow]` for `tempPath` in the `/tmp` fallback test
NIT	Algorithmic (#1)	The `/tmp` fallback in `ResolvePipeDirectory` is effectively dead code in production (only reachable via the testable overload) — worth a clarifying comment
NIT	Security (#3)	Consider `Path.GetFullPath()` normalization on the explicit override for path hygiene

Dimensions checked and clean

✅ Threading & Concurrency — no shared mutable state; all new methods are static/pure or local I/O
✅ Public API — class is internal [Embedded]; constants are public on an internal class (effectively internal); no PublicAPI.Unshipped.txt update needed
✅ IPC Wire Compatibility — no wire format changes; directory resolution is local-only
✅ Performance — GetPipeName is not a hot path; probe I/O only on explicit override
✅ Resource/IDisposable — probe file uses using + File.Delete
✅ Localization — .resx entries added correctly; .xlf regenerated; accessors placed in the !IS_CORE_MTP block (correct — these are needed by extension projects that link the file)
✅ Naming & Conventions — test names describe scenario and outcome
✅ Scope & PR Discipline — focused change, no unrelated refactoring
✅ Build Infrastructure — no dependency changes

No blocking issues found.

github-actions · 2026-07-11T12:18:26Z

🔴 Build Failure Analysis

The build failed with 14 errors (deduplicated to 7 unique issues) in Microsoft.Testing.Platform.csproj, all in two files. Downstream projects (AzureFoundry, AzureDevOpsReport) failed as cascading dependencies.

Root Cause 1: Banned API usage (RS0030) — 3 issues

In NamedPipeServer.cs, the PR uses APIs that are banned in this project:

Line	Banned API	Required Replacement
213	`Environment.GetEnvironmentVariable(...)`	Use `IEnvironment` abstraction
220, 226	`string.IsNullOrWhiteSpace(...)`	Use `RoslynString.IsNullOrWhiteSpace(...)`

Fix for line 213: The private ResolvePipeDirectory() overload should use the _environment field or accept an IEnvironment parameter instead of calling Environment directly.

Fix for lines 220 & 226: Replace string.IsNullOrWhiteSpace(...) with RoslynString.IsNullOrWhiteSpace(...) in ResolvePipeDirectory(string?, string?).

Root Cause 2: Undeclared public API (RS0051) — 4 issues

New internal/public symbols must be declared in PublicAPI.Unshipped.txt:

Line	Symbol
`NamedPipeServer.cs:31`	`const MaxUnixDomainSocketPathLengthInBytes = 103`
`NamedPipeServer.cs:218`	`static ResolvePipeDirectory(string?, string?)`
`NamedPipeServer.cs:261`	`static EnsurePathLengthWithinLimit(string!)`
`EnvironmentVariableConstants.cs:19`	`const TESTINGPLATFORM_PIPE_DIRECTORY`

Fix: Either add these symbols to PublicAPI/PublicAPI.Unshipped.txt, or — if they aren't meant to be public API — consider whether internal visibility with [InternalsVisibleTo] is sufficient (the internal keyword is already used, so this is likely an [InternalsVisibleTo]-exposed symbol that the analyzer still tracks).

Summary of required changes

Replace Environment.GetEnvironmentVariable on line 213 with the IEnvironment abstraction
Replace string.IsNullOrWhiteSpace → RoslynString.IsNullOrWhiteSpace on lines 220 and 226
Add the 4 new symbols to PublicAPI/PublicAPI.Unshipped.txt

🤖 Automated content by GitHub Copilot. Generated by the Build Failure Analysis workflow. · 61.6 AIC · ⌖ 4.9 AIC · ⊞ 7.3K · [◷]( · ◷)

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🤖 Automated content by GitHub Copilot. Generated by the Build Failure Analysis workflow. · 61.6 AIC · ⌖ 4.9 AIC · ⊞ 7.3K · ◷

…ests - Replace banned System.Environment / string.IsNullOrWhiteSpace with SystemEnvironment / RoslynString to fix RS0030. - Declare the four new internal symbols in InternalAPI.Unshipped.txt (RS0016). - Normalize an explicit override with Path.GetFullPath so a relative TESTINGPLATFORM_PIPE_DIRECTORY resolves to a rooted socket path and honors the "full path handed to peers" invariant (also collapses '..'). - Clarify that the '/tmp' fallback is only reachable via the test overload. - Add unit tests for EnsureDirectoryIsWritable (create-missing happy path and non-creatable error path) and a whitespace DataRow for the tempPath fallback. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: ae434eba-3cad-4c61-a1da-ef252ae87f48

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Review details

Files reviewed: 19/19 changed files
Comments generated: 3
Review effort level: Medium

…ed-train # Conflicts: # src/Platform/Microsoft.Testing.Platform/InternalAPI/InternalAPI.Unshipped.txt

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Review details

Files reviewed: 19/19 changed files
Comments generated: 4
Review effort level: Medium

NamedPipeServer.cs is glob-compiled (IPC\*.cs) into HangDump, Retry, TrxReport, and both MSBuild projects, so the earlier fixes must build there: - Read TESTINGPLATFORM_PIPE_DIRECTORY via System.Environment with a scoped RS0030 suppression instead of `new SystemEnvironment()`. Only the MSBuild task project links SystemEnvironment.cs; the other shared-source consumers do not, so the wrapper would not compile there. Reading directly also keeps the file self-contained for the dotnet/sdk vendor copy. - Normalize the selected directory with Path.GetFullPath in every precedence branch (not just the explicit override): Path.GetTempPath() can surface a relative TMPDIR, which NamedPipeServerStream rejects and which would violate the fully-resolved-path invariant. The write probe stays override-only. - Declare the new EnvironmentVariableConstants / NamedPipeServer / PlatformResources members in the HangDump, Retry, TrxReport, and Extensions.MSBuild InternalAPI.Unshipped baselines (they compile these shared files and keep their baselines in sync with core), so RS0016 stays green. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: ae434eba-3cad-4c61-a1da-ef252ae87f48

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Review details

Files reviewed: 23/23 changed files
Comments generated: 2
Review effort level: Medium

…consumers The earlier baseline update missed some projects that link the shared files: - EnvironmentVariableConstants.cs is also linked into HotReload -> add the new TESTINGPLATFORM_PIPE_DIRECTORY const there. - PlatformResources.cs (the !IS_CORE_MTP accessors) is linked into nine API-tracked extensions -> add the two new NamedPipe* accessor signatures to HtmlReport, CtrfReport, JUnitReport, VideoRecorder, and CrashDump (the other four were done previously). Verified each affected project builds clean with -warnaserror:RS0016,RS0017,RS0025,RS0037. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: ae434eba-3cad-4c61-a1da-ef252ae87f48

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Review details

Files reviewed: 29/29 changed files
Comments generated: 2
Review effort level: Medium

…cedence The two diagnostics suggested setting TMPDIR, but TESTINGPLATFORM_PIPE_DIRECTORY always wins, so that advice is misleading when the override is the cause: - Writability error is emitted only for the explicit override, so drop the TMPDIR mention and tell users to fix the override or unset it to fall back to the default temp directory. - Path-too-long can come from any source, so clarify that TMPDIR only helps when the override is not set. Regenerated the XLF files for all 14 languages. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: ae434eba-3cad-4c61-a1da-ef252ae87f48

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Review details

Files reviewed: 29/29 changed files
Comments generated: 1
Review effort level: Medium

…unting The existing path-length tests used only ASCII, so a buggy character-count implementation would still pass. Add a test with 40 '好' (3-byte) chars plus a prefix: 45 characters (under the 103 limit) but 125 UTF-8 bytes (over it), proving the guard measures sun_path bytes rather than characters. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: ae434eba-3cad-4c61-a1da-ef252ae87f48

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Review details

Files reviewed: 29/29 changed files
Comments generated: 0 new
Review effort level: Medium

Copilot

Review details

Files reviewed: 29/29 changed files
Comments generated: 1
Review effort level: Medium

+        // rooted names as socket paths (it rejects separators in non-rooted names). The invariant also requires
+        // handing peers a fully-resolved path. This additionally collapses any '..' segments. '/tmp' and an
+        // already-absolute temp path are unchanged.
+        directory = Path.GetFullPath(directory);


github-actions · 2026-07-11T21:02:35Z

🧪 Test quality grade — PR #9846

Grade	Test	Notes
C (70–79)	new `IPCTests. EnsurePathLengthWithinLimit_ WhenWithinLimit_ DoesNotThrow`	No explicit assertions; relies on implicit "does not throw" for a void guard — consider adding a comment to document the intent, e.g. `// Assert: no exception thrown`.
A (90–100)	new `IPCTests. EnsureDirectoryIsWritable_ WhenDirectoryCannotBeCreated_ ThrowsInvalidOperationException`	Clever setup blocks dir creation deterministically; exact `ThrowsExactly(InvalidOperationException)`. No issues found.
A (90–100)	new `IPCTests. EnsureDirectoryIsWritable_ WhenDirectoryMissingButCreatable_ CreatesItAndDoesNotThrow`	Uses `Path.GetTempPath()` to avoid hard-coded paths; try/finally ensures cleanup; `Directory.Exists` asserts the meaningful side effect.
A (90–100)	new `IPCTests. EnsurePathLengthWithinLimit_ WhenExceedsLimit_ Throws`	Exact exception type; short and focused. No issues found.
A (90–100)	new `IPCTests. EnsurePathLengthWithinLimit_ WhenMultibyteExceedsByteLimitButNotCharLimit_ Throws`	Setup assertions confirm test invariants (char count vs byte count); comment clearly explains the Unicode edge case; exact exception type.
A (90–100)	new `IPCTests. ResolvePipeDirectory_ WhenNeitherOverrideNorTempPathAvailable_ FallsBackToTmp`	Data-driven (null/empty/whitespace); two meaningful assertions on both tuple fields. No issues found.
A (90–100)	new `IPCTests. ResolvePipeDirectory_ WhenOverrideMissing_ FallsBackToTempPath`	Data-driven (null/empty/whitespace); `AreEqual` + `IsFalse` cover both returned fields. No issues found.
A (90–100)	new `IPCTests. ResolvePipeDirectory_ WhenOverrideProvided_ UsesOverrideAsExplicit`	Clear AAA; `AreEqual` + `IsTrue` verify both fields of the returned tuple. No issues found.

_{This advisory comment was generated automatically. Grades are heuristic

and informational — they do not block merging. Re-run with

/grade-tests.}

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Merge remote-tracking branch 'origin/main' into dev/amauryleve/improv…

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…ed-train # Conflicts: # src/Platform/Microsoft.Testing.Platform/InternalAPI/InternalAPI.Unshipped.txt

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Evangelink added the state/needs-review Awaiting review from the team. label Jul 11, 2026

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Merge branch 'main' into dev/amauryleve/improved-train

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Evangelink commented Jul 11, 2026

Problem

Change

Guards

Compatibility notes

Localization

Tests

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Review Summary

Findings by severity

Dimensions checked and clean

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github-actions Bot commented Jul 11, 2026

🔴 Build Failure Analysis

Root Cause 1: Banned API usage (RS0030) — 3 issues

Root Cause 2: Undeclared public API (RS0051) — 4 issues

Summary of required changes

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