gfe-relnote: Fix Http2PriorityWriteScheduler::UpdateStreamParent. Not used in prod. Not protected.

Current UpdateStreamParent() early returns if parent does not change. But exclusive bit should be considered as well.

PiperOrigin-RevId: 260496394
Change-Id: I9401a41140e12d19fbb36e9d5d13dcf58090be47

spdy/core/http2_priority_write_scheduler.h

diff --git a/spdy/core/http2_priority_write_scheduler.h b/spdy/core/http2_priority_write_scheduler.h
index a35e076..f89dc8d 100644
--- a/spdy/core/http2_priority_write_scheduler.h
+++ b/spdy/core/http2_priority_write_scheduler.h
@@ -405,8 +405,10 @@
     return;
   }
 
-  // If the new parent is already the stream's parent, we're done.
-  if (stream_info->parent == new_parent) {
+  if (stream_info->parent == new_parent &&
+      (!exclusive || new_parent->children.size() == 1)) {
+    // If the new parent is already the stream's parent, and exclusivity (if
+    // specified) is already satisfied, we are done.
     return;
   }
 

spdy/core/http2_priority_write_scheduler_test.cc

diff --git a/spdy/core/http2_priority_write_scheduler_test.cc b/spdy/core/http2_priority_write_scheduler_test.cc
index e498c37..0629de9 100644
--- a/spdy/core/http2_priority_write_scheduler_test.cc
+++ b/spdy/core/http2_priority_write_scheduler_test.cc
@@ -426,16 +426,139 @@
   ASSERT_TRUE(peer_.ValidateInvariants());
 }
 
+TEST_F(Http2PriorityWriteSchedulerTest, RegisterStreamParentExclusive) {
+  /*  0
+     / \
+    1   2
+ */
+  scheduler_.RegisterStream(1, SpdyStreamPrecedence(0, 100, false));
+  scheduler_.RegisterStream(2, SpdyStreamPrecedence(0, 100, false));
+  /*  0
+      |
+      3
+     / \
+    1   2
+  */
+  scheduler_.RegisterStream(3, SpdyStreamPrecedence(0, 100, true));
+  EXPECT_THAT(scheduler_.GetStreamChildren(0), ElementsAre(3));
+  EXPECT_THAT(scheduler_.GetStreamChildren(3), UnorderedElementsAre(1, 2));
+  EXPECT_THAT(scheduler_.GetStreamChildren(1), IsEmpty());
+  EXPECT_THAT(scheduler_.GetStreamChildren(2), IsEmpty());
+  ASSERT_TRUE(peer_.ValidateInvariants());
+}
+
+TEST_F(Http2PriorityWriteSchedulerTest, UpdateStreamParentExclusive) {
+  /*  0
+     /|\
+    1 2 3
+ */
+  scheduler_.RegisterStream(1, SpdyStreamPrecedence(0, 100, false));
+  scheduler_.RegisterStream(2, SpdyStreamPrecedence(0, 100, false));
+  scheduler_.RegisterStream(3, SpdyStreamPrecedence(0, 100, false));
+  /*  0
+      |
+      1
+     / \
+    2   3
+  */
+  scheduler_.UpdateStreamPrecedence(1, SpdyStreamPrecedence(0, 100, true));
+  EXPECT_THAT(scheduler_.GetStreamChildren(0), ElementsAre(1));
+  EXPECT_THAT(scheduler_.GetStreamChildren(1), UnorderedElementsAre(2, 3));
+  EXPECT_THAT(scheduler_.GetStreamChildren(2), IsEmpty());
+  EXPECT_THAT(scheduler_.GetStreamChildren(3), IsEmpty());
+  ASSERT_TRUE(peer_.ValidateInvariants());
+}
+
+TEST_F(Http2PriorityWriteSchedulerTest, UpdateStreamParentExclusive2) {
+  /*   0
+       |
+       1
+      / \
+     2   3
+        / \
+       4   5
+       |
+       6
+ */
+  scheduler_.RegisterStream(1, SpdyStreamPrecedence(0, 100, false));
+  scheduler_.RegisterStream(2, SpdyStreamPrecedence(1, 100, false));
+  scheduler_.RegisterStream(3, SpdyStreamPrecedence(1, 100, false));
+  scheduler_.RegisterStream(4, SpdyStreamPrecedence(3, 100, false));
+  scheduler_.RegisterStream(5, SpdyStreamPrecedence(3, 100, false));
+  scheduler_.RegisterStream(6, SpdyStreamPrecedence(4, 100, false));
+  // Update stream 1's parent to 4 exclusive.
+  /*  0
+      |
+      4
+      |
+      1
+     /|\
+    2 3 6
+      |
+      5
+  */
+  scheduler_.UpdateStreamPrecedence(1, SpdyStreamPrecedence(4, 100, true));
+  EXPECT_THAT(scheduler_.GetStreamChildren(0), ElementsAre(4));
+  EXPECT_THAT(scheduler_.GetStreamChildren(4), ElementsAre(1));
+  EXPECT_THAT(scheduler_.GetStreamChildren(1), UnorderedElementsAre(2, 3, 6));
+  EXPECT_THAT(scheduler_.GetStreamChildren(2), IsEmpty());
+  EXPECT_THAT(scheduler_.GetStreamChildren(3), ElementsAre(5));
+  EXPECT_THAT(scheduler_.GetStreamChildren(6), IsEmpty());
+  ASSERT_TRUE(peer_.ValidateInvariants());
+}
+
+TEST_F(Http2PriorityWriteSchedulerTest, UpdateStreamParentNonExclusive) {
+  /*   0
+       |
+       1
+      / \
+     2   3
+        / \
+       4   5
+       |
+       6
+ */
+  scheduler_.RegisterStream(1, SpdyStreamPrecedence(0, 100, false));
+  scheduler_.RegisterStream(2, SpdyStreamPrecedence(1, 100, false));
+  scheduler_.RegisterStream(3, SpdyStreamPrecedence(1, 100, false));
+  scheduler_.RegisterStream(4, SpdyStreamPrecedence(3, 100, false));
+  scheduler_.RegisterStream(5, SpdyStreamPrecedence(3, 100, false));
+  scheduler_.RegisterStream(6, SpdyStreamPrecedence(4, 100, false));
+  // Update stream 1's parent to 4.
+  /*  0
+      |
+      4
+     / \
+    6   1
+       / \
+      2   3
+          |
+          5
+  */
+  scheduler_.UpdateStreamPrecedence(1, SpdyStreamPrecedence(4, 100, false));
+  EXPECT_THAT(scheduler_.GetStreamChildren(0), ElementsAre(4));
+  EXPECT_THAT(scheduler_.GetStreamChildren(4), UnorderedElementsAre(6, 1));
+  EXPECT_THAT(scheduler_.GetStreamChildren(6), IsEmpty());
+  EXPECT_THAT(scheduler_.GetStreamChildren(1), UnorderedElementsAre(2, 3));
+  EXPECT_THAT(scheduler_.GetStreamChildren(2), IsEmpty());
+  EXPECT_THAT(scheduler_.GetStreamChildren(3), ElementsAre(5));
+  EXPECT_THAT(scheduler_.GetStreamChildren(5), IsEmpty());
+  ASSERT_TRUE(peer_.ValidateInvariants());
+}
+
 TEST_F(Http2PriorityWriteSchedulerTest, UpdateStreamParentToParent) {
   scheduler_.RegisterStream(1, SpdyStreamPrecedence(0, 100, false));
   scheduler_.RegisterStream(2, SpdyStreamPrecedence(1, 100, false));
   scheduler_.RegisterStream(3, SpdyStreamPrecedence(1, 100, false));
+  EXPECT_THAT(scheduler_.GetStreamChildren(1), UnorderedElementsAre(2, 3));
+  EXPECT_THAT(scheduler_.GetStreamChildren(2), IsEmpty());
+  EXPECT_THAT(scheduler_.GetStreamChildren(3), IsEmpty());
   for (bool exclusive : {true, false}) {
     scheduler_.UpdateStreamPrecedence(2,
                                       SpdyStreamPrecedence(1, 100, exclusive));
     EXPECT_THAT(scheduler_.GetStreamChildren(0), ElementsAre(1));
-    EXPECT_THAT(scheduler_.GetStreamChildren(1), UnorderedElementsAre(2, 3));
-    EXPECT_THAT(scheduler_.GetStreamChildren(2), IsEmpty());
+    EXPECT_THAT(scheduler_.GetStreamChildren(1), UnorderedElementsAre(2));
+    EXPECT_THAT(scheduler_.GetStreamChildren(2), UnorderedElementsAre(3));
     EXPECT_THAT(scheduler_.GetStreamChildren(3), IsEmpty());
   }
   ASSERT_TRUE(peer_.ValidateInvariants());