Reset the working directory of child processes we spawn on Windows. #1212
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grynspan
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jmschonfeld
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Seems fine to me. Agreed that making a similar change to the posix spawn path seems like a good idea. The temporary directory might also be a good CWD to use instead of the root directory if it's easier to get to / works better but the root directory seems fine too given that exit tests likely shouldn't rely on the CWD
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This PR modifies the Windows implementation of `spawnProcess()` so that it sets the working directory of the new process to "C:\" (or thereabouts). This prevents a race condition on Windows because that system won't let you delete a directory if it's the working directory of any process. See [The Old New Thing](https://devblogs.microsoft.com/oldnewthing/20101109-00/?p=12323) for a very on-the-nose blog post. Note that we do not specify the value of the working directory in an exit test body. A test should generally not rely on it anyway because it is global state and any thread could change its value at any time. I haven't written a unit test for this change because it's unclear what I could write that would be easily verifiable, and because I don't know what state I might perturb outside such a test by calling `SetCurrentDirectory()`. Resolves #1209. (This is a speculative fix.)
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…1212) This PR modifies the Windows implementation of `spawnProcess()` so that it sets the working directory of the new process to "C:\" (or thereabouts). This prevents a race condition on Windows because that system won't let you delete a directory if it's the working directory of any process. See [The Old New Thing](https://devblogs.microsoft.com/oldnewthing/20101109-00/?p=12323) for a very on-the-nose blog post. Note that we do not specify the value of the working directory in an exit test body. A test should generally not rely on it anyway because it is global state and any thread could change its value at any time. I haven't written a unit test for this change because it's unclear what I could write that would be easily verifiable, and because I don't know what state I might perturb outside such a test by calling `SetCurrentDirectory()`. Resolves #1209. (This is a speculative fix.) ### Checklist: - [x] Code and documentation should follow the style of the [Style Guide](https://github.com/apple/swift-testing/blob/main/Documentation/StyleGuide.md). - [x] If public symbols are renamed or modified, DocC references should be updated.
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This PR modifies the Windows implementation of
spawnProcess()so that it sets the working directory of the new process to "C:" (or thereabouts). This prevents a race condition on Windows because that system won't let you delete a directory if it's the working directory of any process. See The Old New Thing for a very on-the-nose blog post.Note that we do not specify the value of the working directory in an exit test body. A test should generally not rely on it anyway because it is global state and any thread could change its value at any time.
I haven't written a unit test for this change because it's unclear what I could write that would be easily verifiable, and because I don't know what state I might perturb outside such a test by calling
SetCurrentDirectory().Resolves #1209.
(This is a speculative fix.)
Checklist: