[PATCH] D144638: [lit] Detect Consistent File Access Times

Mon Feb 27 02:48:12 PST 2023

lenary added a comment.

Updates incoming to add a specific check for netbsd and windows, which are currently excluding the affected tests anyway.

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Comment at: llvm/utils/lit/lit/llvm/config.py:165
+    #
+    # This check hopefully detects both cases, and disables tests that require
+    # consistent atime.
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int3 wrote:
> lenary wrote:
> > jhenderson wrote:
> > > Is "hopefully" really needed here?
> > I'm hedging in this comment, in part because we're trying to find a race condition experimentally, and also because this will cause lit to fatal error before running any tests if `touch` exits non-zero for any reason. 
> if we know for sure that NetBSD and Windows don't support this, why not hardcode those values in, and only try the experimental check otherwise?
Yeah, this seems pragmatic, I will add it back in again - excluding NetBSD and Windows.

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Comment at: llvm/utils/lit/lit/llvm/config.py:171
+            # in the tests that do the same thing.
+            (_, try_touch_err) = self.get_process_output(["touch", "-a", "-t", "199505050555.55", f.name])
+            if try_touch_err != "":
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michaelplatings wrote:
> It looks like this command will be run on Windows. I think it will fail and cause False to be returned, which is the desired result, but this appears to be by accident rather than design. Therefore I'm inclined to agree with @int3 that a hard-coded check would be preferable.
I am going to add the hardcoded checks, but I think `touch` is available in windows, it should be in the same directory as all the git binaries.

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D144638/new/

https://reviews.llvm.org/D144638