revision: make get_revision_mark() return const pointer

Denton-L · gitster · commit 4982516451ed · 2019-11-20T13:33:36.000+09:00
get_revision_mark() used to return a `char *`, even though all of the
strings it was returning were string literals. Make get_revision_mark()
return a `const char *` so that callers won't be tempted to modify the
returned string.

Signed-off-by: Denton Liu &lt;liu.denton@gmail.com&gt;
Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
diff --git a/revision.c b/revision.c
@@ -3934,7 +3934,7 @@ struct commit *get_revision(struct rev_info *revs)
 	return c;
 }
 
-char *get_revision_mark(const struct rev_info *revs, const struct commit *commit)
+const char *get_revision_mark(const struct rev_info *revs, const struct commit *commit)
 {
 	if (commit->object.flags & BOUNDARY)
 		return "-";
@@ -3956,7 +3956,7 @@ char *get_revision_mark(const struct rev_info *revs, const struct commit *commit
 
 void put_revision_mark(const struct rev_info *revs, const struct commit *commit)
 {
-	char *mark = get_revision_mark(revs, commit);
+	const char *mark = get_revision_mark(revs, commit);
 	if (!strlen(mark))
 		return;
 	fputs(mark, stdout);
diff --git a/revision.h b/revision.h
@@ -322,8 +322,8 @@ int handle_revision_arg(const char *arg, struct rev_info *revs,
 void reset_revision_walk(void);
 int prepare_revision_walk(struct rev_info *revs);
 struct commit *get_revision(struct rev_info *revs);
-char *get_revision_mark(const struct rev_info *revs,
-			const struct commit *commit);
+const char *get_revision_mark(const struct rev_info *revs,
+			      const struct commit *commit);
 void put_revision_mark(const struct rev_info *revs,
 		       const struct commit *commit);
 

Original file line number	Diff line number	Diff line change
`@@ -3934,7 +3934,7 @@ struct commit get_revision(struct rev_info revs)`
`3934`	`3934`	`return c;`
`3935`	`3935`	`}`
`3936`	`3936`
`3937`		`-char get_revision_mark(const struct rev_info revs, const struct commit *commit)`
	`3937`	`+const char get_revision_mark(const struct rev_info revs, const struct commit *commit)`
`3938`	`3938`	`{`
`3939`	`3939`	`if (commit->object.flags & BOUNDARY)`
`3940`	`3940`	`return "-";`
`@@ -3956,7 +3956,7 @@ char get_revision_mark(const struct rev_info revs, const struct commit *commit`
`3956`	`3956`
`3957`	`3957`	`void put_revision_mark(const struct rev_info revs, const struct commit commit)`
`3958`	`3958`	`{`
`3959`		`- char *mark = get_revision_mark(revs, commit);`
	`3959`	`+ const char *mark = get_revision_mark(revs, commit);`
`3960`	`3960`	`if (!strlen(mark))`
`3961`	`3961`	`return;`
`3962`	`3962`	`fputs(mark, stdout);`