tree aa060b9f203869f2e255b999b43764337c3a3ae1
parent 5c7d2dc4372a1bade2b877b8b76af6ec86b6722f
author tmoniuszko <tmoniuszko@opera.com> 1455880602 -0800
committer Commit bot <commit-bot@chromium.org> 1455880673 +0000

[GN] Don't rewrite files with the same contents

Reland of https://codereview.chromium.org/1656253003 with fix.

Reason for revert:
Need to revert this patch according https://sites.google.com/a/chromium.org/dev/developers/tree-sheriffs/sheriffing-bug-queues. This patch added a flaky test FilesystemUtils.WriteFileIfChanged.

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It's a test flake:
1) Try to find the patch that caused the flake. It should be recent (e.g. last day or two) in all likelihood.
2) If successful with finding that patch, revert the patch. This is especially true if the flake is from a new test introduced in that patch.
3) Close the bug.

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The test has failed in the following builds:

http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_rel_ng/builds/176911
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_rel_ng/builds/176911
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_rel_ng/builds/176735
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_rel_ng/builds/176715
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_rel_ng/builds/176715
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_rel_ng/builds/176561
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_rel_ng/builds/176462
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_rel_ng/builds/176375

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Example failure:

[ RUN      ] FilesystemUtils.WriteFileIfChanged
../../tools/gn/filesystem_utils_unittest.cc:610: Failure
Expected: (last_modified) != (file_info.last_modified), actual: 2016-02-04 18:06:36.920 UTC vs 2016-02-04 18:06:36.920 UTC
[  FAILED  ] FilesystemUtils.WriteFileIfChanged (3 ms)
[315/315] FilesystemUtils.WriteFileIfChanged (3 ms)
Retrying 1 test (retry #2)
[ RUN      ] FilesystemUtils.WriteFileIfChanged
../../tools/gn/filesystem_utils_unittest.cc:610: Failure
Expected: (last_modified) != (file_info.last_modified), actual: 2016-02-04 18:06:36.936 UTC vs 2016-02-04 18:06:36.936 UTC
[  FAILED  ] FilesystemUtils.WriteFileIfChanged (2 ms)
[316/316] FilesystemUtils.WriteFileIfChanged (2 ms)
Retrying 1 test (retry #3)
[ RUN      ] FilesystemUtils.WriteFileIfChanged
../../tools/gn/filesystem_utils_unittest.cc:610: Failure
Expected: (last_modified) != (file_info.last_modified), actual: 2016-02-04 18:06:36.952 UTC vs 2016-02-04 18:06:36.952 UTC
[  FAILED  ] FilesystemUtils.WriteFileIfChanged (2 ms)
[317/317] FilesystemUtils.WriteFileIfChanged (2 ms)
1 test failed:
    FilesystemUtils.WriteFileIfChanged (../../tools/gn/filesystem_utils_unittest.cc:579)

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More details in http://crbug.com/584548.

Original issue's description:
> [GN] Don't rewrite files with the same contents
>
> BUG=
>
> Committed: https://crrev.com/f8ea5cceefcedd4a01935d5ac4d2ba71e23ac13e
> Cr-Commit-Position: refs/heads/master@{#373544}

BUG=584548

Review URL: https://codereview.chromium.org/1704383002

Cr-Original-Commit-Position: refs/heads/master@{#376430}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 36deb395534c77295db41cc5f3e6b9627fbc5aa8