feat(log): add option to search for header or body to `git log`

Commit Message

Max April 5, 2024, 9:48 p.m. UTC

From: =?UTF-8?q?Max=20=F0=9F=91=A8=F0=9F=8F=BD=E2=80=8D=F0=9F=92=BB=20Copl?=
 =?UTF-8?q?an?= <[e-mail]>

Note to reviewer: I hate the name `--header-or`!  Please help me come up
with a better name.

Summary:
This change adds a new option to `git log` that allows users to search
for commits that match either the author or the commit message. This is
useful for finding commits that were either authored or co-authored by a
specific person.

Currently, the best way to find a commit either authored or co-authored
by a specific person is to use

```sh
echo \
    $(git log --author=Torvalds --pretty="%cd,%H\n" --date=iso-strict) \
    $(git log --grep="Co-authored-by: .*Torvalds" --pretty="%cd,%H\n" --date=iso-strict) \
| sort -n --reverse \
| awk -F, '{print $2}' \
| tr '\n' '\t' \
| xargs git show --stat --stdin
```

This is a bit of a pain, so this change adds a new option to `git log`.
Now finding either authors or co-authors is as simple as

```sh
git log --author=Torvalds --grep=Torvalds --header-or
```

Test plan:
1. create commit authored by A and co-authored-by B
2. create commit authored by B
3. run `git log --author=B --grep="Co-authored-by: B" --header-or`
4. expect to see both commits

Signed-off-by: Max 

Comments

Phillip Wood April 6, 2024, 2:04 p.m. UTC | #1

Hi Max

On 05/04/2024 22:48, Max Coplan via GitGitGadget wrote:
> From: =?UTF-8?q?Max=20=F0=9F=91=A8=F0=9F=8F=BD=E2=80=8D=F0=9F=92=BB=20Copl?=
>   =?UTF-8?q?an?= <[e-mail]>
> 
> Note to reviewer: I hate the name `--header-or`!  Please help me come up
> with a better name.
> 
> Summary:
> This change adds a new option to `git log` that allows users to search
> for commits that match either the author or the commit message. This is
> useful for finding commits that were either authored or co-authored by a
> specific person.

I think that having a way to find all the commits that are authored by, 
or have a specific trailer naming someone is a good idea. I'm not sure 
about combining "--author" with "--grep" to do it though. Perhaps we 
could design a new option (tentatively called "--indent") that allows 
the user to specify a name and which trailers and commit headers (author 
and/or committer) to match.

A couple of house keeping notes. We do not use the "feat(...)" style of 
commit messages in this project. The subject line should just start with 
"log: " the rest of the subject looks fine. I think everything under the 
"Summary:" line above does a good job of explaining why the change is 
useful which is great. We tend to avoid emoji's in peoples names as well.

 > [...]
> +test_expect_success 'log --grep --author --header-or uses union' '
> +	# grep matches only third and fourth
> +	# author matches only initial and third

I'm a bit confused by this comment as we seem to only expect "third" and 
"fourth" below - what happened to "initial"?

> +	git log --author="A U Thor" --grep=r --header-or --format=%s >actual &&
> +	{
> +	    echo fourth && echo third
> +	} >expect &&

We have a test helper to help with this

     test_write_lines fourth third >expect

Best Wishes

Phillip

Patch

diff --git a/grep.c b/grep.c
index ac34bfeafb3..79ba4810b83 100644
--- a/grep.c
+++ b/grep.c
@@ -797,7 +797,7 @@  void compile_grep_patterns(struct grep_opt *opt)
 	if (opt->no_body_match && opt->pattern_expression)
 		opt->pattern_expression = grep_not_expr(opt->pattern_expression);
 
-	if (!header_expr)
+	if (!header_expr || opt->header_or)
 		return;
 
 	if (!opt->pattern_expression)
diff --git a/grep.h b/grep.h
index 926c0875c42..8cbc4a46194 100644
--- a/grep.h
+++ b/grep.h
@@ -147,6 +147,7 @@  struct grep_opt {
 	int count;
 	int word_regexp;
 	int all_match;
+	int header_or;
 	int no_body_match;
 	int body_hit;
 #define GREP_BINARY_DEFAULT	0
diff --git a/revision.c b/revision.c
index 7e45f765d9f..0858050ece3 100644
--- a/revision.c
+++ b/revision.c
@@ -2646,6 +2646,9 @@  static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
 		revs->grep_filter.pattern_type_option = GREP_PATTERN_TYPE_PCRE;
 	} else if (!strcmp(arg, "--all-match")) {
 		revs->grep_filter.all_match = 1;
+	// @@@ must-fix: find a better name
+	} else if (!strcmp(arg, "--header-or")) {
+		revs->grep_filter.header_or = 1;
 	} else if (!strcmp(arg, "--invert-grep")) {
 		revs->grep_filter.no_body_match = 1;
 	} else if ((argcount = parse_long_opt("encoding", argv, &optarg))) {
diff --git a/t/t7810-grep.sh b/t/t7810-grep.sh
index 875dcfd98f3..d539b5e88f5 100755
--- a/t/t7810-grep.sh
+++ b/t/t7810-grep.sh
@@ -961,6 +961,17 @@  test_expect_success 'log --grep --author uses intersection' '
 	test_cmp expect actual
 '
 
+test_expect_success 'log --grep --author --header-or uses union' '
+	# grep matches only third and fourth
+	# author matches only initial and third
+	git log --author="A U Thor" --grep=r --header-or --format=%s >actual &&
+	{
+	    echo fourth && echo third
+	} >expect &&
+	test_cmp expect actual
+'
+
+
 test_expect_success 'log --grep --grep --author takes union of greps and intersects with author' '
 	# grep matches initial and second but not third
 	# author matches only initial and third