Merge branch 'cd/shift-root-in-graph-fix' into jch

The graph drawing logic has been updated to avoid indenting visual
roots when there are columns to their right, which prevents rendering
artifacts.

* cd/shift-root-in-graph-fix:
  graph: do not indent visual roots with columns to their right

graph.c

@@ -969,10 +969,22 @@ static int graph_is_visual_root(struct git_graph *graph,
 	 * already a column, so it will not be rendered below, the
 	 * current commit has to act as the last commit and omit
 	 * indentation.
+	 *
+	 * If there are columns to the right of the commit, they collapse
+	 * into its column once it is rendered, so nothing can be rendered
+	 * right below it and there is no need to indent it.
+	 *
+	 *   * | <- visual root with a column to its right
+	 *    /
+	 *   | *
+	 *
+	 * Indenting it would also push these columns to the right, but
+	 * the collapsing code does not know about that offset.
 	 */
 	return graph_is_visual_root_candidate(graph->commit, graph) &&
 	       !(graph->commit_in_columns &&
 		 graph->columns[graph->commit_index].is_merge_parent) &&
+	       graph->commit_index + 1 >= graph->num_columns &&
 	       flags->is_next_visible &&
 	       (!flags->next_has_column || graph->visual_root_depth > 0);
 }

t/t4218-log-graph-indentation.sh

@@ -449,6 +449,24 @@ test_expect_success 'two unrelated merges' '
 	EOF
 '
 
+test_expect_success 'visual root with columns to its right is not indented' '
+	create_orphan _70 && test_commit 70_A &&
+	git checkout -b _71 && test_commit 71_A &&
+	create_orphan _72 && test_commit 72_A &&
+	TREE=$(git write-tree) &&
+	MERGE=$(git commit-tree $TREE -p _72 -p _70 -m 72_merge) &&
+	git reset --hard $MERGE &&
+	lib_test_check_graph _72 _71 <<-\EOF
+	*   72_merge
+	|\
+	* | 72_A
+	 /
+	| * 71_A
+	|/
+	* 70_A
+	EOF
+'
+
 test_expect_success '--max-count treats the last visible commit as the last commit' '
 	lib_test_check_graph --max-count=2 _8 _9 _10 <<-\EOF
 	  * 10_A