SERVER-11725 fixed interval comparison for INTERVAL_PRECEDES_COULD_UNION

2 files changed, 14 insertions, 1 deletions

diff --git a/src/mongo/db/query/interval.cpp b/src/mongo/db/query/interval.cpp
index 6c80632c4a5..49b75d0c250 100644
--- a/src/mongo/db/query/interval.cpp
+++ b/src/mongo/db/query/interval.cpp
@@ -150,7 +150,9 @@ namespace mongo {
         //
 
         if (precedes(*this, other)) {
-            if (0 == end.woCompare(other.start, false)) {
+            // It's not possible for both endInclusive and other.startInclusive to be true because
+            // the bounds would intersect. Refer to section on "Intersect cases" above.
+            if ((endInclusive || other.startInclusive) && 0 == end.woCompare(other.start, false)) {
                 return INTERVAL_PRECEDES_COULD_UNION;
             }
             return INTERVAL_PRECEDES;
diff --git a/src/mongo/db/query/interval_test.cpp b/src/mongo/db/query/interval_test.cpp
index 1b95fa2dda1..bbb1f90f20c 100644
--- a/src/mongo/db/query/interval_test.cpp
+++ b/src/mongo/db/query/interval_test.cpp
@@ -134,6 +134,17 @@ namespace {
         ASSERT_NOT_EQUALS(f.compare(a), Interval::INTERVAL_PRECEDES);
     }
 
+    TEST(Comparison, PrecedesCouldUnion) {
+        Interval a(BSON("" << 10 << "" << 20), false, true);
+        ASSERT_NOT_EQUALS(a.compare(a), Interval::INTERVAL_PRECEDES);
+
+        Interval b(BSON("" << 0 << "" << 10), true, false);
+        ASSERT_EQUALS(b.compare(a), Interval::INTERVAL_PRECEDES);
+
+        Interval c(BSON("" << 0 << "" << 10), true, true);
+        ASSERT_EQUALS(c.compare(a), Interval::INTERVAL_PRECEDES_COULD_UNION);
+    }
+
     TEST(Comparison, Succeds) {
         Interval a(BSON("" << 10 << "" << 20), true, true);
         ASSERT_NOT_EQUALS(a.compare(a), Interval::INTERVAL_SUCCEEDS);