Wrong gitignore precedence?

Hello All,

I read the document of gitignore (http://git-scm.com/docs/gitignore), and learned that $GIT_DIR/info/exclude has higher precedence than the file specified by core.excludesfile.

But I noticed that patterns in core.excludesfile override patterns in $GIT_DIR/info/exclude.

I tested as below:

   1. Make a new git repository for test, and move into the repository.
      $ git init testrepo
      $ cd testrepo
   2. Change core.excludesfile configuration.
      $ touch ../core_excludesfile
      $ git config core.excludesfile `realpath ../core_excludesfile`
   3. Create test~. In each step I check if the file is ignored or not.
      $ touch test~
   4. See git status. In this case I expect that test~ should not be ignored.
      $ git status --ignored
   5. Change settings in .git/info/exclude.
      $ echo '*~' > .git/info/exclude
   6. See git status. In this case I expect that test~ should be ignored.
      $ git status --ignored
   7. Change settings in .git/info/exclude and core.excludesfile.
      $ echo '*~' > ../core_excludesfile
      $ echo '!*~' > .git/info/exclude
   8. See git status. In this case I expect that test~ should not be ignored.
      $ git status --ignored
   9. Change settings in .git/info/exclude and core.excludesfile
      $ echo '!*~' > ../core_excludesfile
      $ echo '*~' > .git/info/exclude
  10. See git status. In this case I expect that test~ should be ignored.
      $ git status --ignored

Steps 4. and 6. worked as I expected, but 8. and 10. didn't.

I read the source code of Git, and found out the point that seems to cause the problem.

In dir.c, setup_standard_excludes() adds patterns in .git/info/exclude to the excludes list first, and patterns in core.excludesfile are added next.

In last_exclude_matching_from_list(), pattern is searched from the end of the list, and the first matching pattern is used. Therefore the patterns in core.excludesfile are used in precedence to .git/info/exclude.

To meet the precedence described in the document of gitignore, I guess setup_standard_excludes() should be fixed so that patterns in core.excludesfile are added to the list before those in .git/info/ecdlude are added.

Thanks

Yohei Endo <yoheie@gmail.com> writes:

I tend to agree that info/exclude which is per-repository personal preference should take precedence over $XDG_HOME/git/ignore which is a personal preference across repositories that are accessed from that machine.

It appears that the precedence was screwed-up between these two files from the very beginning when 896bdfa2 (add: Support specifying an excludes file with a configuration variable, 2007-02-27) introduced core.excludesfile variable; seeing that nobody so far complained with the discrepancy between the documentation and the behaviour, it would indicate either (1) nobody reads the docs, or (2) nobody uses both at the same time.

Swapping the order in the code this late in the game after 8 years may affect people who have come to rely on the current behaviour and never read the doc, which is somewhat worrying, though.

On Wed, 22 Apr 2015 11:59:04 -0700 Junio C Hamano <gitster@pobox.com> wrote:

I agree. I think the change should be well announced before the fix is applied, like when the implicit value of push.default was changed.

Thanks.

$GIT_DIR/info/exclude and core.excludesfile (which falls back to $XDG_HOME/git/ignore) are both ways to override the ignore pattern lists given by the project in .gitignore files. The former, which is per-repository personal preference, should take precedence over the latter, which is a personal preference default across different repositories that are accessed from that machine. The existing documentation also agrees.

However, the precedence order was screwed up between these two from the very beginning when 896bdfa2 (add: Support specifying an excludes file with a configuration variable, 2007-02-27) introduced core.excludesfile variable.

Noticed-by: Yohei Endo <yoheie@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---

 * This is done on an old codebase and may not apply cleanly to more
   modern codebase easily.

 dir.c              | 10 +++++++---
 t/t0008-ignores.sh | 10 ++++++++++
 2 files changed, 17 insertions(+), 3 deletions(-)