Merge branch 'ds/graph-horizontal-edges'

Rendering by "git log --graph" of ancestry lines leading to a merge
commit were made suboptimal to waste vertical space a bit with a
recent update, which has been corrected.

* ds/graph-horizontal-edges:
  graph: fix collapse of multiple edges
  graph: add test to demonstrate horizontal line bug

2 files changed, 70 insertions, 2 deletions

diff --git a/graph.c b/graph.c
index aaf97069bd..4fb25ad464 100644
--- a/graph.c
+++ b/graph.c
@@ -1233,8 +1233,14 @@ static void graph_output_collapsing_line(struct git_graph *graph, struct graph_l
 			 * prevent any other edges from moving
 			 * horizontally.
 			 */
-			if (horizontal_edge == -1)
-				horizontal_edge = i;
+			if (horizontal_edge == -1) {
+				int j;
+				horizontal_edge_target = target;
+				horizontal_edge = i - 1;
+
+				for (j = (target * 2) + 3; j < (i - 2); j += 2)
+					graph->mapping[j] = target;
+			}
 		}
 	}
 
diff --git a/t/t4215-log-skewed-merges.sh b/t/t4215-log-skewed-merges.sh
index 5661ed5881..1d0d3240ff 100755
--- a/t/t4215-log-skewed-merges.sh
+++ b/t/t4215-log-skewed-merges.sh
@@ -311,4 +311,66 @@ test_expect_success 'log --graph with multiple tips and colors' '
 	test_cmp expect.colors actual.colors
 '
 
+test_expect_success 'log --graph with multiple tips' '
+	git checkout --orphan 7_1 &&
+	test_commit 7_A &&
+	test_commit 7_B &&
+	test_commit 7_C &&
+	git checkout -b 7_2 7_1~2 &&
+	test_commit 7_D &&
+	test_commit 7_E &&
+	git checkout -b 7_3 7_1~1 &&
+	test_commit 7_F &&
+	test_commit 7_G &&
+	git checkout -b 7_4 7_2~1 &&
+	test_commit 7_H &&
+	git checkout -b 7_5 7_1~2 &&
+	test_commit 7_I &&
+	git checkout -b 7_6 7_3~1 &&
+	test_commit 7_J &&
+	git checkout -b M_1 7_1 &&
+	git merge --no-ff 7_2 -m 7_M1 &&
+	git checkout -b M_3 7_3 &&
+	git merge --no-ff 7_4 -m 7_M2 &&
+	git checkout -b M_5 7_5 &&
+	git merge --no-ff 7_6 -m 7_M3 &&
+	git checkout -b M_7 7_1 &&
+	git merge --no-ff 7_2 7_3 -m 7_M4 &&
+
+	check_graph M_1 M_3 M_5 M_7 <<-\EOF
+	*   7_M1
+	|\
+	| | *   7_M2
+	| | |\
+	| | | * 7_H
+	| | | | *   7_M3
+	| | | | |\
+	| | | | | * 7_J
+	| | | | * | 7_I
+	| | | | | | *   7_M4
+	| |_|_|_|_|/|\
+	|/| | | | |/ /
+	| | |_|_|/| /
+	| |/| | | |/
+	| | | |_|/|
+	| | |/| | |
+	| | * | | | 7_G
+	| | | |_|/
+	| | |/| |
+	| | * | | 7_F
+	| * | | | 7_E
+	| | |/ /
+	| |/| |
+	| * | | 7_D
+	| | |/
+	| |/|
+	* | | 7_C
+	| |/
+	|/|
+	* | 7_B
+	|/
+	* 7_A
+	EOF
+'
+
 test_done