[PATCH v1 3/5] diff-merges: support list of values for --diff-merges

[Sergey Organov <sorganov@gmail.com>]

Support comma-separated list of options in --diff-merges=. This allows
for shorter:

  --diff-merges=on,hide

instead of:

  --diff-merges=on --diff-merges=hide

Signed-off-by: Sergey Organov <sorganov@gmail.com>
---
 Documentation/diff-options.txt |  5 +++--
 diff-merges.c                  | 22 ++++++++++++++++++----
 t/t4013-diff-various.sh        |  8 ++++++++
 3 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/Documentation/diff-options.txt b/Documentation/diff-options.txt
index fe15693492a2..977f9135b0d6 100644
--- a/Documentation/diff-options.txt
+++ b/Documentation/diff-options.txt
@@ -38,7 +38,8 @@ ifdef::git-log[]
 --no-diff-merges::
 	Specify diff format to be used for merge commits. Default is
 	{diff-merges-default} unless `--first-parent` is in use, in which case
-	`first-parent` is the default.
+	`first-parent` is the default. Comma-separated list of
+	supported values is accepted as well.
 +
 --diff-merges=(off|none):::
 --no-diff-merges:::
@@ -53,7 +54,7 @@ ifdef::git-log[]
 	`log.diffMerges` configuration parameter, which default value
 	is `separate`.
 +
-	`-m` is a shortcut for '--diff-merges=on --diff-merges=hide'.
+	`-m` is a shortcut for '--diff-merges=on,hide'.
 	In addition it implies `-p` when `log.diffMerges-m-imply-p` is
 	active.
 +
diff --git a/diff-merges.c b/diff-merges.c
index 1fbf476d378e..bb2797ff8cc5 100644
--- a/diff-merges.c
+++ b/diff-merges.c
@@ -1,6 +1,7 @@
 #include "diff-merges.h"
 
 #include "revision.h"
+#include "strbuf.h"
 
 typedef void (*diff_merges_setup_func_t)(struct rev_info *);
 static void set_separate(struct rev_info *revs);
@@ -109,12 +110,25 @@ static diff_merges_setup_func_t func_by_opt(const char *optarg)
 
 static void set_diff_merges(struct rev_info *revs, const char *optarg)
 {
-	diff_merges_setup_func_t func = func_by_opt(optarg);
+	char const delim = ',';
+	struct strbuf **opts = strbuf_split_str(optarg, delim, -1);
+	struct strbuf **p;
 
-	if (!func)
-		die(_("invalid value for '%s': '%s'"), "--diff-merges", optarg);
+	for (p = opts; *p; p++) {
+		diff_merges_setup_func_t func;
+		char *opt = (*p)->buf;
+		int len = (*p)->len;
 
-	func(revs);
+		if (opt[len - 1] == delim)
+			opt[len - 1] = '\0';
+		func = func_by_opt(opt);
+		if (!func) {
+			strbuf_list_free(opts);
+			die(_("invalid value for '%s': '%s'"), "--diff-merges", opt);
+		}
+		func(revs);
+	}
+	strbuf_list_free(opts);
 }
 
 /*
diff --git a/t/t4013-diff-various.sh b/t/t4013-diff-various.sh
index 1789dd6063c5..a07513e67fd6 100755
--- a/t/t4013-diff-various.sh
+++ b/t/t4013-diff-various.sh
@@ -485,6 +485,14 @@ test_expect_success 'log --diff-merges=on matches --diff-merges=separate' '
 	test_cmp expected actual
 '
 
+test_expect_success 'log --diff-merges=<V1>,<V2>' '
+	git log --diff-merges=1,hide master >result &&
+	process_diffs result >expected &&
+	git log --diff-merges=1 --diff-merges=hide master >result &&
+	process_diffs result >actual &&
+	test_cmp expected actual
+'
+
 test_expect_success 'deny wrong log.diffMerges config' '
 	test_config log.diffMerges wrong-value &&
 	test_expect_code 128 git log
-- 
2.25.1