Thomas Gummerer <t.gummerer@xxxxxxxxx> writes:
> Subject: [PATCH] stash: setup default diff output format if necessary
>
> In the scripted 'git stash show' when no arguments are passed, we just
> pass '--stat' to 'git diff'. When any argument is passed to 'stash
> show', we no longer pass '--stat' to 'git diff', and pass whatever
> flags are passed directly through to 'git diff'.
>
> By default 'git diff' shows the patch output. So when we a user uses
> 'git stash show -v', they would be shown the diff, because that's the
> default behaviour of 'git diff', but not actually directly triggered
> by passing the '-v'.
>
> In the C version of 'git stash show', we try to emulate that
> behaviour using the internal diff API. However we forgot to set up
> the default output format, in case it wasn't set by any of the flags
> that were passed through.
Well explained. It might have avoided such a bug if the code did
not manually stuff the diffopt.* structure fields (instead, e.g.
prepare an array of strings like {"diff", "--stat", NULL} and let
the option parser diff_opt_parse() to do its job), but that is
lamenting over water under the bridge.
> So 'git stash show -v' in the builtin
> version of stash would be completely silent, while it would show the
> diff before.
That sounds reasonable. Thanks for a quick diagnosis and a fix.
> Fix this by setting up the default output format for 'git diff'.
>
> Reported-by: Denton Liu <liu.denton@xxxxxxxxx>
> Signed-off-by: Thomas Gummerer <t.gummerer@xxxxxxxxx>
> ---
> builtin/stash.c | 4 ++++
> t/t3903-stash.sh | 18 ++++++++++++++++++
> 2 files changed, 22 insertions(+)
>
> diff --git a/builtin/stash.c b/builtin/stash.c
> index 51df092633..012662ce68 100644
> --- a/builtin/stash.c
> +++ b/builtin/stash.c
> @@ -761,6 +761,10 @@ static int show_stash(int argc, const char **argv, const char *prefix)
> free_stash_info(&info);
> usage_with_options(git_stash_show_usage, options);
> }
> + if (!rev.diffopt.output_format) {
> + rev.diffopt.output_format = DIFF_FORMAT_PATCH;
> + diff_setup_done(&rev.diffopt);
> + }
Hmph. Does this result in setup_done() called twice? As it would
indicate another bug in the original code if setup_done() was never
called, I am assuming that another setup_done() call in the same
codeflow is already there.
> rev.diffopt.flags.recursive = 1;
> setup_diff_pager(&rev.diffopt);
> diff --git a/t/t3903-stash.sh b/t/t3903-stash.sh
> index 97cc71fbaf..e0a50ab267 100755
> --- a/t/t3903-stash.sh
> +++ b/t/t3903-stash.sh
> @@ -612,6 +612,24 @@ test_expect_success 'stash show -p - no stashes on stack, stash-like argument' '
> test_cmp expected actual
> '
>
> +test_expect_success 'stash show -v shows diff' '
> + git reset --hard &&
> + echo foo >>file &&
> + STASH_ID=$(git stash create) &&
> + git reset --hard &&
> + cat >expected <<-EOF &&
> + diff --git a/file b/file
> + index 7601807..71b52c4 100644
> + --- a/file
> + +++ b/file
> + @@ -1 +1,2 @@
> + baz
> + +foo
> + EOF
> + git stash show -v ${STASH_ID} >actual &&
> + test_cmp expected actual
> +'
> +
> test_expect_success 'drop: fail early if specified stash is not a stash ref' '
> git stash clear &&
> test_when_finished "git reset --hard HEAD && git stash clear" &&
