Re: [PATCH v2] diff: don't read index when --no-index is given

Eric Sunshine [off-list ref] writes:

On Mon, Dec 9, 2013 at 3:40 PM, Thomas Gummerer [off-list ref] wrote:

quoted

git diff --no-index ... currently reads the index, during setup, when
calling gitmodules_config().  This results in worse performance when
the index is not actually needed.  This patch avoids calling
gitmodules_config() when the --no-index option is given.  The times for
executing "git diff --no-index" in the WebKit repository are improved as
follows:

Test                      HEAD~3            HEAD
------------------------------------------------------------------
4001.1: diff --no-index   0.24(0.15+0.09)   0.01(0.00+0.00) -95.8%

An additional improvement of this patch is that "git diff --no-index" no
longer breaks when the index file is corrupt, which makes it possible to
use it for investigating the broken repository.

To improve the possible usage as investigation tool for broken
repositories, setup_git_directory_gently() is also not called when the
--no-index option is given.

Also add a test to guard against future breakages, and a performance
test to show the improvements.

Signed-off-by: Thomas Gummerer <redacted>
---

diff --git a/t/t4053-diff-no-index.sh b/t/t4053-diff-no-index.sh
index 979e983..d3dbf6b 100755
--- a/t/t4053-diff-no-index.sh
+++ b/t/t4053-diff-no-index.sh

@@ -29,4 +29,10 @@ test_expect_success 'git diff --no-index relative path outside repo' '
        )
 '

+test_expect_success 'git diff --no-index with broken index' '
+       cd repo &&
+       echo broken >.git/index &&
+       git diff --no-index a ../non/git/a &&
+'

Stray && on the last line of the test.

Also, don't you want to do the 'cd' and subsequent commands inside a
subshell so that tests added after this one won't have to worry about
cd'ing back to the top-level?

Thanks both to you and Torsten for catching both issues, I'll fix them
in a re-roll.

quoted

+
 test_done
--
1.8.5.4.g8639e57

--
Thomas