Right now mozbuild knows how to copy, and how to symlink. We should teach it to hardlink as well, for usage in 1380416.

Comment on attachment 8888433 [details] Bug 1382739 - Added support for hardlinks to mozbuild; https://reviewboard.mozilla.org/r/159380/#review165356 This is essentially an r+. Just need some minor test fixups. ::: python/mozbuild/mozpack/files.py:442 (Diff revision 1) > + else: > + return True Nit: you can move this into the try: block. ::: python/mozbuild/mozpack/test/test_files.py:422 (Diff revision 1) > + if not self.hardlink_supported: > + return IIRC the better way to do this is: `raise unittest.SkipTest('hardlink not supported')` ::: python/mozbuild/mozpack/test/test_files.py:453 (Diff revision 1) > + s = HardlinkFile(source) > + self.assertFalse(s.copy(dest)) > + > + source_stat = os.stat(source) > + dest_stat = os.stat(dest) > + self.assertEqual(source_stat.st_dev, dest_stat.st_dev) > + self.assertEqual(source_stat.st_ino, dest_stat.st_ino) It feels like this test should lstat() the previous link and make sure it isn't updated as part of calling `s.copy()`. I'm not sure what attributes are available on hard links though. Maybe you could os.utime() the link to a very old time?

Comment on attachment 8888433 [details] Bug 1382739 - Added support for hardlinks to mozbuild; https://reviewboard.mozilla.org/r/159380/#review165356 > It feels like this test should lstat() the previous link and make sure it isn't updated as part of calling `s.copy()`. I'm not sure what attributes are available on hard links though. Maybe you could os.utime() the link to a very old time? Not sure I understand this -- do hardlinks keep separate metadata from their target? I switched the test to use `lstat` so that if ther was a symlink somehow the test would fail.

Comment on attachment 8888433 [details] Bug 1382739 - Added support for hardlinks to mozbuild; https://reviewboard.mozilla.org/r/159380/#review165356 > Not sure I understand this -- do hardlinks keep separate metadata from their target? I switched the test to use `lstat` so that if ther was a symlink somehow the test would fail. It appears that they do not. So the best we can do is compare st_nlink and st_ino for the proper semantics.

Comment on attachment 8888433 [details] Bug 1382739 - Added support for hardlinks to mozbuild; https://reviewboard.mozilla.org/r/159380/#review165356 > It appears that they do not. So the best we can do is compare st_nlink and st_ino for the proper semantics. Just so I follow, you'd like a `self.assertEqual(source_stat.st_nlink, dest_stat.st_link)` as well?

Comment on attachment 8888433 [details] Bug 1382739 - Added support for hardlinks to mozbuild; https://reviewboard.mozilla.org/r/159380/#review165794 I guess you can change those lstat() back to stat() if you want. Sorry for misleading you. I always thought lstat() on a hard link yielded something more useful.

Comment on attachment 8888433 [details] Bug 1382739 - Added support for hardlinks to mozbuild; https://reviewboard.mozilla.org/r/159380/#review165794 `lstat` still makes more sense I think, so I'll leave it.

Pushed by ryanvm@gmail.com: https://hg.mozilla.org/integration/autoland/rev/9efa1cfe64b1 Added support for hardlinks to mozbuild; r=gps