On Wed, Mar 13, 2019 at 12:20:14PM -0700, Johannes Schindelin via GitGitGadget wrote:
> From: Johannes Schindelin <johannes.schindelin@xxxxxx>
>
> As far as this developer can tell, the conversion from a Perl script to
> a built-in caused the regression in the difftool that it no longer runs
> outside of a Git worktree (with `--no-index`, of course).
>
> It is a bit embarrassing that it took over two years after retiring the
> Perl version to discover this regression, but at least we now know, and
> can do something, about it.
If a bug falls in the forest, does it make a sound?
I get the impression that `--no-index` is not used all that much, given
how long bugs seem to hang around in it (and doubly so when intersected
with the difftool).
> - setenv(GIT_DIR_ENVIRONMENT, absolute_path(get_git_dir()), 1);
> - setenv(GIT_WORK_TREE_ENVIRONMENT, absolute_path(get_git_work_tree()), 1);
> + for (i = 0; i < argc; i++)
> + if (!strcmp(argv[i], "--"))
> + break;
> + else if (!strcmp(argv[i], "--no-index")) {
> + no_index = 1;
> + break;
> + }
Instead of this ad-hoc parsing, can we just add an OPT_BOOL("no-index")
to the parse-options array? We'll have already run parse_options() at
this point.
We'd just have to remember to add it back to the argv of diff
sub-commands we run.
> + if (!no_index && !startup_info->have_repository)
> + die(_("difftool requires worktree or --no-index"));
> +
> + if (!no_index){
> + setup_work_tree();
> + setenv(GIT_DIR_ENVIRONMENT, absolute_path(get_git_dir()), 1);
> + setenv(GIT_WORK_TREE_ENVIRONMENT, absolute_path(get_git_work_tree()), 1);
> + }
This part makes sense.
There may be other subtle dependencies on having a repo from
sub-functions we run, but I didn't see any from a quick scan. And
anyway, if there is such a code path, it is no worse off than before
your patch (and in fact much better, because it would hopefully yield a
BUG() that would tell us what we need to fix).
> index 2014aab6b8..46365ed86a 100644
> --- a/git.c
> +++ b/git.c
> @@ -491,7 +491,7 @@ static struct cmd_struct commands[] = {
> { "diff-files", cmd_diff_files, RUN_SETUP | NEED_WORK_TREE | NO_PARSEOPT },
> { "diff-index", cmd_diff_index, RUN_SETUP | NO_PARSEOPT },
> { "diff-tree", cmd_diff_tree, RUN_SETUP | NO_PARSEOPT },
> - { "difftool", cmd_difftool, RUN_SETUP | NEED_WORK_TREE },
> + { "difftool", cmd_difftool, RUN_SETUP_GENTLY },
We necessarily lost NEED_WORK_TREE, but that's OK because you added in a
setup_work_tree() in the function. Good.
> +test_expect_success 'outside worktree' '
> + mkdir outside &&
> + echo 1 >outside/1 &&
> + echo 2 >outside/2 &&
> + test_expect_code 1 env GIT_CEILING_DIRECTORIES="$(pwd)" git \
> + -c diff.tool=echo -c difftool.echo.cmd="echo \$LOCAL \$REMOTE" \
> + -C outside difftool --no-prompt --no-index 1 2 >out &&
We have a helper for running outside a repo. Because you have to set up
the "outside" space, it unfortunately doesn't shorten things as much as
it does in some other spots:
diff --git a/t/t7800-difftool.sh b/t/t7800-difftool.sh
index 4907627656..255a787614 100755
--- a/t/t7800-difftool.sh
+++ b/t/t7800-difftool.sh
@@ -706,12 +706,12 @@ test_expect_success SYMLINKS 'difftool --dir-diff handles modified symlinks' '
'
test_expect_success 'outside worktree' '
- mkdir outside &&
- echo 1 >outside/1 &&
- echo 2 >outside/2 &&
- test_expect_code 1 env GIT_CEILING_DIRECTORIES="$(pwd)" git \
+ mkdir non-repo &&
+ echo 1 >non-repo/1 &&
+ echo 2 >non-repo/2 &&
+ test_expect_code 1 nongit git \
-c diff.tool=echo -c difftool.echo.cmd="echo \$LOCAL \$REMOTE" \
- -C outside difftool --no-prompt --no-index 1 2 >out &&
+ difftool --no-prompt --no-index 1 2 >out &&
test "1 2" = "$(cat out)"
'
but it might be worth using anyway, just for consistency.
> + test "1 2" = "$(cat out)"
A minor nit, but I think:
echo "1 2" >expect &&
test_cmp expect actual
produces nicer output on failure, and costs the same number of
processes (it is an extra file write, but I think the main driver of
performance in the test suite is just processes).
-Peff
