[PATCH] git-log: add a --since-as-filter option

[Miklos Vajna <vmiklos@vmiklos.hu>]

This is similar to --since, but it will filter out not matching commits,
rather than stopping at the first not matching commit.

This is useful if you e.g. want to list the commits from the last year,
but one odd commit has a bad commit date and that would hide lots of
earlier commits in that range.

The behavior of --since is left unchanged, since it's valid to depend on
its current behavior.
---

Hi,

On Fri, Apr 01, 2022 at 10:51:34AM -0700, Junio C Hamano <gitster@pobox.com> wrote:
> We could add a --since-as-filter= option or something, but then the
> user needs to be careful when to stop (and digging down to the root
> of the history, i.e. "never stop", may be an acceptable answer to
> some projects).

Here is a patch that does this. As a somewhat arbitrary testcase, the
LibreOffice core.git repo has 474064 commits and --since-as-filter
finishes in 688 ms for a sample query (and expected output), while I got
empty output with --since previously. I would argue this is an
acceptable trade-off.

What do you think?

Thanks,

Miklos

 Documentation/rev-list-options.txt |  5 +++++
 revision.c                         | 10 ++++++++++
 revision.h                         |  1 +
 t/t4217-log-limit.sh               | 32 ++++++++++++++++++++++++++++++
 4 files changed, 48 insertions(+)
 create mode 100755 t/t4217-log-limit.sh

diff --git a/Documentation/rev-list-options.txt b/Documentation/rev-list-options.txt
index fd4f4e26c9..ba01b1ba06 100644
--- a/Documentation/rev-list-options.txt
+++ b/Documentation/rev-list-options.txt
@@ -25,6 +25,11 @@ ordering and formatting options, such as `--reverse`.
 --after=<date>::
 	Show commits more recent than a specific date.
 
+--since-as-filter=<date>::
+	Show all commits more recent than a specific date. This visits all
+	commits in the range, rather than stopping at the first commit which is older
+	than a specific date.
+
 --until=<date>::
 --before=<date>::
 	Show commits older than a specific date.
diff --git a/revision.c b/revision.c
index 2646b78990..ebc95319d6 100644
--- a/revision.c
+++ b/revision.c
@@ -1440,6 +1440,9 @@ static int limit_list(struct rev_info *revs)
 		if (revs->min_age != -1 && (commit->date > revs->min_age) &&
 		    !revs->line_level_traverse)
 			continue;
+		if (revs->max_age_as_filter != -1 && (commit->date < revs->max_age_as_filter) &&
+		    !revs->line_level_traverse)
+			continue;
 		date = commit->date;
 		p = &commit_list_insert(commit, p)->next;
 
@@ -1838,6 +1841,7 @@ void repo_init_revisions(struct repository *r,
 	revs->dense = 1;
 	revs->prefix = prefix;
 	revs->max_age = -1;
+	revs->max_age_as_filter = -1;
 	revs->min_age = -1;
 	revs->skip_count = -1;
 	revs->max_count = -1;
@@ -2218,6 +2222,9 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
 	} else if ((argcount = parse_long_opt("since", argv, &optarg))) {
 		revs->max_age = approxidate(optarg);
 		return argcount;
+	} else if ((argcount = parse_long_opt("since-as-filter", argv, &optarg))) {
+		revs->max_age_as_filter = approxidate(optarg);
+		return argcount;
 	} else if ((argcount = parse_long_opt("after", argv, &optarg))) {
 		revs->max_age = approxidate(optarg);
 		return argcount;
@@ -3862,6 +3869,9 @@ enum commit_action get_commit_action(struct rev_info *revs, struct commit *commi
 	if (revs->min_age != -1 &&
 	    comparison_date(revs, commit) > revs->min_age)
 			return commit_ignore;
+	if (revs->max_age_as_filter != -1 &&
+	    comparison_date(revs, commit) < revs->max_age_as_filter)
+			return commit_ignore;
 	if (revs->min_parents || (revs->max_parents >= 0)) {
 		int n = commit_list_count(commit->parents);
 		if ((n < revs->min_parents) ||
diff --git a/revision.h b/revision.h
index 5bc59c7bfe..e80c148b19 100644
--- a/revision.h
+++ b/revision.h
@@ -263,6 +263,7 @@ struct rev_info {
 	int skip_count;
 	int max_count;
 	timestamp_t max_age;
+	timestamp_t max_age_as_filter;
 	timestamp_t min_age;
 	int min_parents;
 	int max_parents;
diff --git a/t/t4217-log-limit.sh b/t/t4217-log-limit.sh
new file mode 100755
index 0000000000..5b7d30d5ad
--- /dev/null
+++ b/t/t4217-log-limit.sh
@@ -0,0 +1,32 @@
+#!/bin/sh
+
+test_description='git log with filter options limiting the output'
+GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
+export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
+
+. ./test-lib.sh
+
+GIT_TEST_COMMIT_GRAPH=0
+GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS=0
+
+test_expect_success 'setup test' '
+	git init &&
+	echo a > file &&
+	git add file &&
+	GIT_COMMITTER_DATE="2022-02-01 0:00" git commit -m init &&
+	echo a >> file &&
+	git add file &&
+	GIT_COMMITTER_DATE="2021-01-01 0:00" git commit -m second &&
+	echo a >> file &&
+	git add file &&
+	GIT_COMMITTER_DATE="2022-03-01 0:00" git commit -m third
+'
+
+test_expect_success 'git log --since-as-filter' '
+	git log --since-as-filter="2022-01-01" --pretty="format:%s" > actual &&
+	test_i18ngrep init actual &&
+	! test_i18ngrep second actual &&
+	test_i18ngrep third actual
+'
+
+test_done
-- 
2.34.1