Subject: Re: [PATCH] apply: canonicalize modes read from patches

From: Junio C Hamano <[email-masked]>
Date: Thu, 15 Aug 2024 07:52:47 -0700

Jeff King <[email-masked]> writes:

> +test_expect_success POSIXPERM 'patch mode for deleted file is canonicalized' '

This test seems to fail under "--stress" and I need to borrow a
brain better clued than mine.  It appears to be fooled by mtime that
is not updated immediately and failing match_stat check, but since
the index file is written on the other side of the second resolution
boundary, racy-git double-checking code does not trigger, or
something like that.

Here is how it fails:

expecting success of 4129.13 'patch mode for deleted file is canonicalized':
        test_when_finished "git reset --hard" &&
        echo content >non-canon &&
        git add non-canon &&
        chmod 666 non-canon &&

        cat >patch <<-\EOF &&
        diff --git a/non-canon b/non-canon
        deleted file mode 100660
        --- a/non-canon
        +++ /dev/null
        @@ -1 +0,0 @@
        -content
        EOF
        git apply --index patch 2>err &&
        test_must_be_empty err &&
        git ls-files -- non-canon >staged &&
        test_must_be_empty staged &&
        test_path_is_missing non-canon

++ test_when_finished 'git reset --hard'
++ test 0 = 0
++ test_cleanup='{ git reset --hard
                } && (exit "$eval_ret"); eval_ret=$?; :'
++ echo content
++ git add non-canon
++ chmod 666 non-canon
++ cat
++ git apply --index patch
error: last command exited with $?=1
not ok 13 - patch mode for deleted file is canonicalized
#
#               test_when_finished "git reset --hard" &&
#               echo content >non-canon &&
#               git add non-canon &&
#               chmod 666 non-canon &&
#
#               cat >patch <<-\EOF &&
#               diff --git a/non-canon b/non-canon
#               deleted file mode 100660
#               --- a/non-canon
#               +++ /dev/null
#               @@ -1 +0,0 @@
#               -content
#               EOF
#               git apply --index patch 2>err &&
#               test_must_be_empty err &&
#               git ls-files -- non-canon >staged &&
#               test_must_be_empty staged &&
#               test_path_is_missing non-canon
#
1..13
$ echo $?
1
$ git -C trash\ directory.t4129-apply-samemode.stress-failed/.git ls-files --debug non-canon
non-canon
  ctime: 1723701364:980719772
  mtime: 1723701364:980719772
  dev: 65024    ino: 1980747
  uid: 110493   gid: 89939
  size: 8       flags: 0
: git t/master; stat trash\ directory.t4129-apply-samemode.stress-failed/non-canon
  File: trash directory.t4129-apply-samemode.stress-failed/non-canon
  Size: 8               Blocks: 8          IO Block: 4096   regular file
Device: 254,0   Inode: 1980747     Links: 1
Access: (0666/-rw-rw-rw-)  Uid: (110493/     jch)   Gid: (89939/primarygroup)
Access: 2024-08-15 06:54:43.808293635 -0700
Modify: 2024-08-14 22:56:04.980719772 -0700
Change: 2024-08-14 22:56:05.020719706 -0700
 Birth: 2024-08-14 22:56:04.980719772 -0700
$ stat trash\ directory.t4129-apply-samemode.stress-failed/.git/index
  File: trash directory.t4129-apply-samemode.stress-failed/.git/index
  Size: 432             Blocks: 8          IO Block: 4096   regular file
Device: 254,0   Inode: 1980724     Links: 1
Access: (0600/-rw-------)  Uid: (110493/     jch)   Gid: (89939/primarygroup)
Access: 2024-08-14 22:56:05.044719667 -0700
Modify: 2024-08-14 22:56:05.008719726 -0700
Change: 2024-08-14 22:56:05.016719713 -0700
 Birth: 2024-08-14 22:56:04.996719746 -0700