[PATCH v2] Teach git apply to respect core.fileMode settings

From: Chandra Pratap <chandrapratap3519@gmail.com>

When applying a patch that adds an executable file, git apply ignores the core.fileMode setting (core.fileMode in git config specifies whether the executable bit on files in the working tree should be honored or not) resulting in warnings like:

warning: script.sh has type 100644, expected 100755

even when core.fileMode is set to false, which is undesired. This is extra true for systems like Windows, which don't rely on "lsat()".

Fix this by inferring the correct file mode from the existing index entry when core.filemode is set to false. The added test case helps verify the change and prevents future regression.

Reviewed-by: Johannes Schindelin <johannes.schindelin@gmail.com>
Signed-off-by: Chandra Pratap <chandrapratap3519@gmail.com>
---
    apply: make git apply respect core.fileMode settings
    
    Closes issue #1555 on GitHub.

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1620%2FChand-ra%2Fdevel-v2
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1620/Chand-ra/devel-v2
Pull-Request: https://github.com/gitgitgadget/git/pull/1620

Range-diff vs v1:

 1:  d896351158c ! 1:  29c8c6d120e Teach git apply to respect core.fileMode settings
     @@ Metadata
       ## Commit message ##
          Teach git apply to respect core.fileMode settings
      
     -    CC: Johannes Schindelin <johannes.schindelin@gmail.com>
     +    When applying a patch that adds an executable file, git apply
     +    ignores the core.fileMode setting (core.fileMode in git config
     +    specifies whether the executable bit on files in the working tree
     +    should be honored or not) resulting in warnings like:
     +
     +    warning: script.sh has type 100644, expected 100755
     +
     +    even when core.fileMode is set to false, which is undesired. This
     +    is extra true for systems like Windows, which don't rely on "lsat()".
     +
     +    Fix this by inferring the correct file mode from the existing
     +    index entry when core.filemode is set to false. The added
     +    test case helps verify the change and prevents future regression.
     +
     +    Reviewed-by: Johannes Schindelin <johannes.schindelin@gmail.com>
          Signed-off-by: Chandra Pratap <chandrapratap3519@gmail.com>
      
       ## apply.c ##
     @@ apply.c: static int check_preimage(struct apply_state *state,
      -	if (!state->cached && !previous)
      -		st_mode = ce_mode_from_stat(*ce, st->st_mode);
      +	if (!state->cached && !previous) {
     -+		if (!trust_executable_bit && patch->old_mode)
     -+			st_mode = patch->old_mode;
     -+		else st_mode = ce_mode_from_stat(*ce, st->st_mode);
     ++		if (!trust_executable_bit)
     ++			st_mode = *ce ? (*ce)->ce_mode : patch->old_mode;
     ++		else
     ++			st_mode = ce_mode_from_stat(*ce, st->st_mode);
      +	}
       
       	if (patch->is_new < 0)
     @@ t/t4129-apply-samemode.sh: test_expect_success POSIXPERM 'do not use core.shared
       	)
       '
       
     -+test_expect_success FILEMODE 'ensure git apply respects core.fileMode' '
     ++test_expect_success 'ensure git apply respects core.fileMode' '
      +	test_config core.fileMode false &&
      +	echo true >script.sh &&
      +	git add --chmod=+x script.sh &&
     ++	git ls-files -s script.sh | grep "^100755" &&
      +	test_tick && git commit -m "Add script" &&
     ++	git ls-tree -r HEAD script.sh | grep "^100755" &&
      +
      +	echo true >>script.sh &&
      +	test_tick && git commit -m "Modify script" script.sh &&
      +	git format-patch -1 --stdout >patch &&
     ++	grep "index.*100755" patch &&
      +
      +	git switch -c branch HEAD^ &&
     ++	git apply --index patch 2>err &&
     ++	! grep "has type 100644, expected 100755" err &&
     ++	git restore -S script.sh && git restore script.sh &&
     ++
      +	git apply patch 2>err &&
     -+	! test_grep "has type 100644, expected 100755" err
     ++	! grep "has type 100644, expected 100755" err &&
     ++
     ++	git apply --cached patch 2>err &&
     ++	! grep "has type 100644, expected 100755" err
      +'
      +
       test_done

 apply.c                   |  8 ++++++--
 t/t4129-apply-samemode.sh | 25 +++++++++++++++++++++++++
 2 files changed, 31 insertions(+), 2 deletions(-)