Re: [PATCH] diff-tree: read the index so attribute checks work in bare repositories
On Tue, Dec 5, 2017 at 5:13 PM, Brandon Williams <bmwill@google.com> wrote:
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> A regression was introduced in 557a5998d (submodule: remove
> gitmodules_config, 2017-08-03) to how attribute processing was handled
> in bare repositories when running the diff-tree command.
>
> By default the attribute system will first try to read ".gitattribute"
> files from the working tree and then falls back to reading them from the
> index if there isn't a copy checked out in the worktree. Prior to
> 557a5998d the index was read as a side effect of the call to
> 'gitmodules_config()' which ensured that the index was already populated
> before entering the attribute subsystem.
>
> Since the call to 'gitmodules_config()' was removed the index is no
> longer being read so when the attribute system tries to read from the
> in-memory index it doesn't find any ".gitattribute" entries effectively
> ignoring any configured attributes.
>
> Fix this by explicitly reading the index during the setup of diff-tree.
This commit message does a good job of explaining the issue, so someone who hasn't followed the thread (or has not followed it closely, like me) can understand the problem and solution. Thanks.
A few comments below...
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> Reported-by: Ben Boeckel <ben.boeckel@kitware.com>
> Signed-off-by: Brandon Williams <bmwill@google.com>
> ---
> diff --git a/builtin/diff-tree.c b/builtin/diff-tree.c
> @@ -110,6 +110,7 @@ int cmd_diff_tree(int argc, const char **argv, const char *prefix)
>
> git_config(git_diff_basic_config, NULL); /* no "diff" UI options */
> init_revisions(opt, prefix);
> + read_cache();
557a5998d (submodule: remove gitmodules_config, 2017-08-03) touched a fair number of built-in commands. It's not clear from the current patch's commit message if diff-tree is the only command which regressed. Is it? Or are other commands also likely to have regressed? Perhaps the commit message could say something about this. For instance: "All other commands touched by 557a5998d have been audited and were found to be regression-free" or "Other commands may regress in the same way, but we will take a wait-and-see attitude and fix them as needed because <fill-in-reason>".
> diff --git a/t/t4015-diff-whitespace.sh b/t/t4015-diff-whitespace.sh
> @@ -636,6 +636,23 @@ test_expect_success 'check with space before tab in indent (diff-tree)' '
> +test_expect_success 'check with ignored trailing whitespace attr (diff-tree)' '
> + test_when_finished "git reset --hard HEAD^" &&
> + # Create a whitespace error that should be ignored.
Comments in nearby tests are not capitalized and do not end with period.
> + echo "* -whitespace" > ".gitattributes" &&
Please drop unnecessary quotes around the filename, as the extra noise makes it a bit harder to read. Also, lose space after redirection operator:
echo "* -whitespace" >.gitattributes &&
> + git add ".gitattributes" &&
> + echo "trailing space -> " > "trailing-space" &&
All the nearby tests use some variation of:
echo "foo (); " >x &&
which differs from the "trailing space ->" and filename 'trailing-space' used in this test. Lack of consistency makes this new test stick out like a sore thumb.
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> + git add "trailing-space" &&
> + git commit -m "trailing space" &&
> +
> + # With a worktree diff-tree ignores the whitespace error
> + git diff-tree --root --check HEAD &&
> +
> + # Without a worktree diff-tree still ignores the whitespace error
> + git -C .git diff-tree --root --check HEAD
> +'
