last-modified: document option '--max-depth'

Option --max-depth is supported by git-last-modified(1), because it was
added to the diff machinery in a1dfa54 (diff: teach tree-diff a
max-depth parameter, 2025-08-07).

This option is useful for everyday use of the git-last-modified(1)
command, so document it's existence in the man page.

To have it also appear in the help output of `git last-modified -h`,
move the handling of '--max-depth' to parse_options() in
builtin/last-modified.c itself. This prepares for the change in default
behavior in the next commit.

Signed-off-by: Toon Claes <toon@iotcl.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: To1ne

Documentation/git-last-modified.adoc

@@ -9,7 +9,7 @@ git-last-modified - EXPERIMENTAL: Show when files were last modified
 SYNOPSIS
 --------
 [synopsis]
-git last-modified [--recursive] [--show-trees] [-z]
+git last-modified [--recursive] [--show-trees] [--max-depth=<depth>] [-z]
 		  [<revision-range>] [[--] <pathspec>...]
 
 DESCRIPTION
@@ -33,6 +33,12 @@ OPTIONS
 	Show tree entries even when recursing into them. It has no effect
 	without `--recursive`.
 
+`--max-depth=<depth>`::
+	For each pathspec given on the command line, traverse at most `<depth>`
+	levels into subtrees. A negative value means no limit.
+	The default is 0, which shows all paths matching the pathspec
+	without descending into subtrees.
+
 `-z`::
 	Terminate each line with a _NUL_ character rather than a newline.
 

builtin/last-modified.c

@@ -56,6 +56,7 @@ struct last_modified {
 	bool recursive;
 	bool show_trees;
 	bool nul_termination;
+	int max_depth;
 
 	const char **all_paths;
 	size_t all_paths_nr;
@@ -483,6 +484,12 @@ static int last_modified_init(struct last_modified *lm, struct repository *r,
 	lm->rev.diffopt.flags.recursive = lm->recursive;
 	lm->rev.diffopt.flags.tree_in_recursive = lm->show_trees;
 
+	if (lm->max_depth >= 0) {
+		lm->rev.diffopt.flags.recursive = 1;
+		lm->rev.diffopt.max_depth = lm->max_depth;
+		lm->rev.diffopt.max_depth_valid = 1;
+	}
+
 	argc = setup_revisions(argc, argv, &lm->rev, NULL);
 	if (argc > 1) {
 		error(_("unknown last-modified argument: %s"), argv[1]);
@@ -511,7 +518,7 @@ int cmd_last_modified(int argc, const char **argv, const char *prefix,
 	struct last_modified lm = { 0 };
 
 	const char * const last_modified_usage[] = {
-		N_("git last-modified [--recursive] [--show-trees] [-z]\n"
+		N_("git last-modified [--recursive] [--show-trees] [--max-depth=<depth>] [-z]\n"
 		   "                  [<revision-range>] [[--] <pathspec>...]"),
 		NULL
 	};
@@ -521,11 +528,19 @@ int cmd_last_modified(int argc, const char **argv, const char *prefix,
 			 N_("recurse into subtrees")),
 		OPT_BOOL('t', "show-trees", &lm.show_trees,
 			 N_("show tree entries when recursing into subtrees")),
+		OPT_INTEGER_F(0, "max-depth", &lm.max_depth,
+			      N_("maximum tree depth to recurse"), PARSE_OPT_NONEG),
 		OPT_BOOL('z', NULL, &lm.nul_termination,
 			 N_("lines are separated with NUL character")),
 		OPT_END()
 	};
 
+	/*
+	 * Set the default of a max-depth to "unset". This will change in a
+	 * subsequent commit.
+	 */
+	lm.max_depth = -1;
+
 	argc = parse_options(argc, argv, prefix, last_modified_options,
 			     last_modified_usage,
 			     PARSE_OPT_KEEP_ARGV0 | PARSE_OPT_KEEP_UNKNOWN_OPT);