add-patch: respect diff.context configuration

Various builtins that use add-patch infrastructure do not respect
the user's diff.context and diff.interHunkContext file configurations.

The user may be used to seeing their diffs with customized context size,
but not in the patches "git add -p" shows them to pick from.

Teach add-patch infrastructure to read these configuration variables and
pass their values when spawning the underlying plumbing commands as
their command line option.

Signed-off-by: Leon Michalak <leonmichalak6@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

4 files changed, 38 insertions, 3 deletions

diff --git a/add-interactive.c b/add-interactive.c
index 97ff35b6f1..eb3d0d3ada 100644
--- a/add-interactive.c
+++ b/add-interactive.c
@@ -41,6 +41,8 @@ void init_add_i_state(struct add_i_state *s, struct repository *r)
 	const char *value;
 
 	s->r = r;
+	s->context = -1;
+	s->interhunkcontext = -1;
 
 	if (repo_config_get_value(r, "color.interactive", &value))
 		s->use_color = -1;
@@ -78,6 +80,13 @@ void init_add_i_state(struct add_i_state *s, struct repository *r)
 	repo_config_get_string(r, "diff.algorithm",
 			       &s->interactive_diff_algorithm);
 
+	if (!repo_config_get_int(r, "diff.context", &s->context))
+		if (s->context < 0)
+			die(_("%s cannot be negative"), "diff.context");
+	if (!repo_config_get_int(r, "diff.interHunkContext", &s->interhunkcontext))
+		if (s->interhunkcontext < 0)
+			die(_("%s cannot be negative"), "diff.interHunkContext");
+
 	repo_config_get_bool(r, "interactive.singlekey", &s->use_single_key);
 	if (s->use_single_key)
 		setbuf(stdin, NULL);
diff --git a/add-interactive.h b/add-interactive.h
index 693f125e8e..c63f35b14b 100644
--- a/add-interactive.h
+++ b/add-interactive.h
@@ -18,6 +18,7 @@ struct add_i_state {
 
 	int use_single_key;
 	char *interactive_diff_filter, *interactive_diff_algorithm;
+	int context, interhunkcontext;
 };
 
 void init_add_i_state(struct add_i_state *s, struct repository *r);
diff --git a/add-patch.c b/add-patch.c
index 95c67d8c80..b0125b51ba 100644
--- a/add-patch.c
+++ b/add-patch.c
@@ -414,7 +414,6 @@ static int normalize_marker(const char *p)
 static int parse_diff(struct add_p_state *s, const struct pathspec *ps)
 {
 	struct strvec args = STRVEC_INIT;
-	const char *diff_algorithm = s->s.interactive_diff_algorithm;
 	struct strbuf *plain = &s->plain, *colored = NULL;
 	struct child_process cp = CHILD_PROCESS_INIT;
 	char *p, *pend, *colored_p = NULL, *colored_pend = NULL, marker = '\0';
@@ -424,8 +423,12 @@ static int parse_diff(struct add_p_state *s, const struct pathspec *ps)
 	int res;
 
 	strvec_pushv(&args, s->mode->diff_cmd);
-	if (diff_algorithm)
-		strvec_pushf(&args, "--diff-algorithm=%s", diff_algorithm);
+	if (s->s.context != -1)
+		strvec_pushf(&args, "--unified=%i", s->s.context);
+	if (s->s.interhunkcontext != -1)
+		strvec_pushf(&args, "--inter-hunk-context=%i", s->s.interhunkcontext);
+	if (s->s.interactive_diff_algorithm)
+		strvec_pushf(&args, "--diff-algorithm=%s", s->s.interactive_diff_algorithm);
 	if (s->revision) {
 		struct object_id oid;
 		strvec_push(&args,
diff --git a/t/t3701-add-interactive.sh b/t/t3701-add-interactive.sh
index b088ee141f..18dc329ea1 100755
--- a/t/t3701-add-interactive.sh
+++ b/t/t3701-add-interactive.sh
@@ -1230,4 +1230,26 @@ test_expect_success 'hunk splitting works with diff.suppressBlankEmpty' '
 	test_cmp expect actual
 '
 
+test_expect_success 'add -p respects diff.context' '
+	test_write_lines a b c d e f g h i j k l m >file &&
+	git add file &&
+	test_write_lines a b c d e f G h i j k l m >file &&
+	echo y | git -c diff.context=5 add -p >actual &&
+	test_grep "@@ -2,11 +2,11 @@" actual
+'
+
+test_expect_success 'add -p respects diff.interHunkContext' '
+	test_write_lines a b c d e f g h i j k l m n o p q r s >file &&
+	git add file &&
+	test_write_lines a b c d E f g i i j k l m N o p q r s >file &&
+	echo y | git -c diff.interhunkcontext=2 add -p >actual &&
+	test_grep "@@ -2,16 +2,16 @@" actual
+'
+
+test_expect_success 'add -p rejects negative diff.context' '
+	test_config diff.context -1 &&
+	test_must_fail git add -p 2>output &&
+	test_grep "diff.context cannot be negative" output
+'
+
 test_done