Test failures in @actions/exec package when run under MacOS

[bdehamer]

Sometime between 2024-10-08 and 2024-10-28 there are three unit tests from the @actions/exec package which have started failing when run specifically on MacOS.

• Last successful run
• First failing run

The failures do not appear to be related to any code changes in the repo (I can repro the issue with exactly the same code which was running successfully on October 8th). My guess is that the failures may have something to do with the runner image. The last passing test was running under [email protected] while the failures are occurring under [email protected].

The three failing tests are the following:

• @actions/exec › Handles child process holding streams open
• @actions/exec › Handles child process holding streams open and non-zero exit code
• @actions/exec › Handles child process holding streams open and stderr

One interesting data point . . . these same tests will PASS when run in GitHub Actions if I change the runner type from macos-latest to macos-latest-large:

• Successful run under macos-latest-large

[reconbot]

We think this is related to OSX 14.7 being released.

[nodeselector]

• breaking image, notably macOS 14.7 (23H124)
• working image, notably macOS 14.6.1 (23G93)

Switching to an Intel based runner fixed this. I opened a Feedback item for this FB15679172. Moreover, running the test suite locally on a machine on macOS 14.7 23H124 reproduces the test failure as well, indicating this isn't likely to be an issue with the virtualization stack or the image configuration, but some change in macOS itself.