On Tue, Jan 25 2022, Johannes Schindelin via GitGitGadget wrote:
> From: Johannes Schindelin <johannes.schindelin@xxxxxx>
>
> The `--diff-filter=<bits>` option allows to filter the diff by certain
> criteria, for example `R` to only show renamed files. It also supports
> negating a filter via a down-cased letter, i.e. `r` to show _everything
> but_ renamed files.
>
> However, the code is a bit overzealous when trying to figure out whether
> `git diff` should start with all diff-filters turned on because the user
> provided a lower-case letter: if the `--diff-filter` argument starts
> with an upper-case letter, we must not start with all bits turned on.
>
> Signed-off-by: Johannes Schindelin <johannes.schindelin@xxxxxx>
> ---
> diff.c | 8 +++-----
> t/t4202-log.sh | 8 ++++++++
> 2 files changed, 11 insertions(+), 5 deletions(-)
>
> diff --git a/diff.c b/diff.c
> index c862771a589..fc1151b9c73 100644
> --- a/diff.c
> +++ b/diff.c
> @@ -4821,17 +4821,15 @@ static int diff_opt_diff_filter(const struct option *option,
> prepare_filter_bits();
>
> /*
> - * If there is a negation e.g. 'd' in the input, and we haven't
> + * If the input starts with a negation e.g. 'd', and we haven't
> * initialized the filter field with another --diff-filter, start
> * from full set of bits, except for AON.
> */
> if (!opt->filter) {
> - for (i = 0; (optch = optarg[i]) != '\0'; i++) {
> - if (optch < 'a' || 'z' < optch)
> - continue;
> + optch = optarg[0];
> + if (optch >= 'a' && 'z' >= optch) {
We'll probably never have to deal with non-ASCII, so maybe this is being
overzelous, but perhaps changing this to islower(optch) is worth it?
This relies on non-standard C both in the pre- and post-image, but in
reality it works everywhere, until someone attempts to port git to an
EBCDIC system...
> opt->filter = (1 << (ARRAY_SIZE(diff_status_letters) - 1)) - 1;
> opt->filter &= ~filter_bit[DIFF_STATUS_FILTER_AON];
> - break;
> }
> }
>
> diff --git a/t/t4202-log.sh b/t/t4202-log.sh
> index 50495598619..28f727937dd 100755
> --- a/t/t4202-log.sh
> +++ b/t/t4202-log.sh
> @@ -142,6 +142,14 @@ test_expect_success 'diff-filter=R' '
>
> '
>
> +test_expect_success 'diff-filter=Ra' '
> +
nit: extra \n
> + git log -M --pretty="format:%s" --diff-filter=R HEAD >expect &&
> + git log -M --pretty="format:%s" --diff-filter=Ra HEAD >actual &&
> + test_cmp expect actual
> +
> +'
> +
> test_expect_success 'diff-filter=C' '
>
> git log -C -C --pretty="format:%s" --diff-filter=C HEAD >actual &&
