Merge branch 'ax/line-log-range-merge-fix' into maint

The code to parse "git log -L..." command line was buggy when there
are many ranges specified with -L; overrun of the allocated buffer
has been fixed.

* ax/line-log-range-merge-fix:
  line-log.c: prevent crash during union of too many ranges

2 files changed, 17 insertions, 8 deletions

diff --git a/line-log.c b/line-log.c
index 65f3558b3..951029665 100644
--- a/line-log.c
+++ b/line-log.c
@@ -144,7 +144,7 @@ void sort_and_merge_range_set(struct range_set *rs)
 static void range_set_union(struct range_set *out,
 			     struct range_set *a, struct range_set *b)
 {
-	int i = 0, j = 0, o = 0;
+	int i = 0, j = 0;
 	struct range *ra = a->ranges;
 	struct range *rb = b->ranges;
 	/* cannot make an alias of out->ranges: it may change during grow */
@@ -167,16 +167,15 @@ static void range_set_union(struct range_set *out,
 			new = &rb[j++];
 		if (new->start == new->end)
 			; /* empty range */
-		else if (!o || out->ranges[o-1].end < new->start) {
+		else if (!out->nr || out->ranges[out->nr-1].end < new->start) {
 			range_set_grow(out, 1);
-			out->ranges[o].start = new->start;
-			out->ranges[o].end = new->end;
-			o++;
-		} else if (out->ranges[o-1].end < new->end) {
-			out->ranges[o-1].end = new->end;
+			out->ranges[out->nr].start = new->start;
+			out->ranges[out->nr].end = new->end;
+			out->nr++;
+		} else if (out->ranges[out->nr-1].end < new->end) {
+			out->ranges[out->nr-1].end = new->end;
 		}
 	}
-	out->nr = o;
 }
 
 /*
diff --git a/t/t4211-line-log.sh b/t/t4211-line-log.sh
index 9d87777b5..d0377fae5 100755
--- a/t/t4211-line-log.sh
+++ b/t/t4211-line-log.sh
@@ -106,4 +106,14 @@ test_expect_success '-L with --output' '
 	test_line_count = 70 log
 '
 
+test_expect_success 'range_set_union' '
+	test_seq 500 > c.c &&
+	git add c.c &&
+	git commit -m "many lines" &&
+	test_seq 1000 > c.c &&
+	git add c.c &&
+	git commit -m "modify many lines" &&
+	git log $(for x in $(test_seq 200); do echo -L $((2*x)),+1:c.c; done)
+'
+
 test_done