Subject: [PATCH 1/1] git-grep: improve the --show-function behaviour

From: Oleg Nesterov <[email-masked]>
Date: Mon, 11 Sep 2023 14:12:11 +0200

show_funcname_line() returns when "lno <= opt->last_shown" and this
is not right in that the ->last_shown line (which matched the pattern)
can also have the actual function name we need to report.

Change this code to check "lno < opt->last_shown". While at it, move
this check up to avoid the unnecessary "find the previous bol" loop.

Note that --lno can't underflow, lno==0 is not possible in this loop.

Simple test-case:

	$ cat TEST.c
	void func(void);

	void func1(xxx)
	{
		use1(xxx);
	}

	void func2(xxx)
	{
		use2(xxx);
	}

	$ git grep --untracked -pn xxx TEST.c

before the patch:

	TEST.c=1=void func(void);
	TEST.c:3:void func1(xxx)
	TEST.c:5:       use1(xxx);
	TEST.c:8:void func2(xxx)
	TEST.c:10:      use2(xxx);

after the patch:

	TEST.c=1=void func(void);
	TEST.c:3:void func1(xxx)
	TEST.c=3=void func1(xxx)
	TEST.c:5:       use1(xxx);
	TEST.c:8:void func2(xxx)
	TEST.c=8=void func2(xxx)
	TEST.c:10:      use2(xxx);

which looks much better to me.

Signed-off-by: Oleg Nesterov <[email-masked]>
---
 grep.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/grep.c b/grep.c
index 0904d55b24..7cad8352f4 100644
--- a/grep.c
+++ b/grep.c
@@ -1350,12 +1350,11 @@ static void show_funcname_line(struct grep_opt *opt, struct grep_source *gs,
 	while (bol > gs->buf) {
 		const char *eol = --bol;
 
+		if (--lno < opt->last_shown)
+			break;
+
 		while (bol > gs->buf && bol[-1] != '\n')
 			bol--;
-		lno--;
-
-		if (lno <= opt->last_shown)
-			break;
 
 		if (match_funcname(opt, gs, bol, eol)) {
 			show_line(opt, bol, eol, gs->name, lno, 0, '=');
-- 
2.25.1.362.g51ebf55