graph API: fix bug in graph_is_interesting()

Previously, graph_is_interesting() did not behave quite the same way as
the code in get_revision().  As a result, it would sometimes think
commits were uninteresting, even though get_revision() would return
them.  This resulted in incorrect lines in the graph output.

This change creates a get_commit_action() function, which
graph_is_interesting() and simplify_commit() both now use to determine
if a commit will be shown.  It is identical to the old simplify_commit()
behavior, except that it never calls rewrite_parents().

This problem was reported by Santi Béjar.  The following command
would exhibit the problem before, but now works correctly:

  git log --graph --simplify-by-decoration --oneline v1.6.3.3

Previously git graph did not display the output for this command
correctly between f29ac4f and 66996ec, among other places.

Signed-off-by: Adam Simpkins <simpkins@facebook.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/graph.c b/graph.c
index e466770208..9087f65849 100644
--- a/graph.c
+++ b/graph.c
@@ -286,9 +286,10 @@ static int graph_is_interesting(struct git_graph *graph, struct commit *commit)
 	}
 
 	/*
-	 * Uninteresting and pruned commits won't be printed
+	 * Otherwise, use get_commit_action() to see if this commit is
+	 * interesting
 	 */
-	return (commit->object.flags & (UNINTERESTING | TREESAME)) ? 0 : 1;
+	return get_commit_action(graph->revs, commit) == commit_show;
 }
 
 static struct commit_list *next_interesting_parent(struct git_graph *graph,