Merge branch 'np/log-graph-octopus-fix' into maint

[thirdparty/git.git] / graph.c

diff --git a/graph.c b/graph.c
index e1f6d3bddb38aadd4e439aea30f542d286ecb98e..f53135485f565baf7a0de1a5e4cffe2a4b2b55bd 100644 (file)
--- a/graph.c
+++ b/graph.c
@@ -842,27 +842,55 @@ static void graph_output_commit_char(struct git_graph *graph, struct strbuf *sb)
 }
 
 /*
- * Draw an octopus merge and return the number of characters written.
+ * Draw the horizontal dashes of an octopus merge and return the number of
+ * characters written.
  */
 static int graph_draw_octopus_merge(struct git_graph *graph,
                                    struct strbuf *sb)
 {
        /*
-        * Here dashless_commits represents the number of parents
-        * which don't need to have dashes (because their edges fit
-        * neatly under the commit).
-        */
-       const int dashless_commits = 2;
-       int col_num, i;
-       int num_dashes =
-               ((graph->num_parents - dashless_commits) * 2) - 1;
-       for (i = 0; i < num_dashes; i++) {
-               col_num = (i / 2) + dashless_commits + graph->commit_index;
-               strbuf_write_column(sb, &graph->new_columns[col_num], '-');
+        * Here dashless_parents represents the number of parents which don't
+        * need to have dashes (the edges labeled "0" and "1").  And
+        * dashful_parents are the remaining ones.
+        *
+        * | *---.
+        * | |\ \ \
+        * | | | | |
+        * x 0 1 2 3
+        *
+        */
+       const int dashless_parents = 2;
+       int dashful_parents = graph->num_parents - dashless_parents;
+
+       /*
+        * Usually, we add one new column for each parent (like the diagram
+        * above) but sometimes the first parent goes into an existing column,
+        * like this:
+        *
+        * | *---.
+        * | |\ \ \
+        * |/ / / /
+        * x 0 1 2
+        *
+        * In which case the number of parents will be one greater than the
+        * number of added columns.
+        */
+       int added_cols = (graph->num_new_columns - graph->num_columns);
+       int parent_in_old_cols = graph->num_parents - added_cols;
+
+       /*
+        * In both cases, commit_index corresponds to the edge labeled "0".
+        */
+       int first_col = graph->commit_index + dashless_parents
+           - parent_in_old_cols;
+
+       int i;
+       for (i = 0; i < dashful_parents; i++) {
+               strbuf_write_column(sb, &graph->new_columns[i+first_col], '-');
+               strbuf_write_column(sb, &graph->new_columns[i+first_col],
+                                   i == dashful_parents-1 ? '.' : '-');
        }
-       col_num = (i / 2) + dashless_commits + graph->commit_index;
-       strbuf_write_column(sb, &graph->new_columns[col_num], '.');
-       return num_dashes + 1;
+       return 2 * dashful_parents;
 }
 
 static void graph_output_commit_line(struct git_graph *graph, struct strbuf *sb)