revwalk: fix uninteresting revs sometimes not limiting graphwalk

When we want to limit our graphwalk, we use the heuristic of checking
whether the newest limiting (uninteresting) revision is newer than the
oldest interesting revision. We do so by inspecting whether the first
item's commit time of the user-supplied list of revisions is newer than
the last added interesting revision. This is wrong though, as the user
supplied list is in no way guaranteed to be sorted by increasing commit
dates. This could lead us to abort the revwalk early before applying all
relevant limiting revisions, outputting revisions which should in fact
have been hidden.

Fix the heuristic by instead checking whether _any_ of the limiting
commits was made earlier than the last interesting commit. Add a test.

1 files changed, 27 insertions, 0 deletions

diff --git a/tests/revwalk/basic.c b/tests/revwalk/basic.c
index 6a23701f3..1106bf4ce 100644
--- a/tests/revwalk/basic.c
+++ b/tests/revwalk/basic.c
@@ -555,3 +555,30 @@ void test_revwalk_basic__old_hidden_commit_two(void)
 
 	cl_git_fail_with(GIT_ITEROVER, git_revwalk_next(&oid, _walk));
 }
+
+/*
+ * Ensure that we correctly hide all parent commits of a newer
+ * commit when first hiding older commits.
+ *
+ * % git rev-list D ^B ^A ^E
+ * 790ba0facf6fd103699a5c40cd19dad277ff49cd
+ * b82cee5004151ae0c4f82b69fb71b87477664b6f
+ */
+void test_revwalk_basic__newer_hidden_commit_hides_old_commits(void)
+{
+	git_oid oid;
+
+	revwalk_basic_setup_walk("revwalk.git");
+
+	cl_git_pass(git_revwalk_push_ref(_walk, "refs/heads/D"));
+	cl_git_pass(git_revwalk_hide_ref(_walk, "refs/heads/B"));
+	cl_git_pass(git_revwalk_hide_ref(_walk, "refs/heads/A"));
+	cl_git_pass(git_revwalk_hide_ref(_walk, "refs/heads/E"));
+
+	cl_git_pass(git_revwalk_next(&oid, _walk));
+	cl_assert(git_oid_streq(&oid, "b82cee5004151ae0c4f82b69fb71b87477664b6f"));
+	cl_git_pass(git_revwalk_next(&oid, _walk));
+	cl_assert(git_oid_streq(&oid, "790ba0facf6fd103699a5c40cd19dad277ff49cd"));
+
+	cl_git_fail_with(GIT_ITEROVER, git_revwalk_next(&oid, _walk));
+}