Fixed a potential null deref and added a unit test to catch that edge case.

amablue · a-maurice · commit 98a8d5779a55 · 2019-08-14T13:35:50.000-07:00
PiperOrigin-RevId: 258265168
diff --git a/database/src/desktop/core/operation.cc b/database/src/desktop/core/operation.cc
@@ -118,8 +118,9 @@ static Optional<Operation> OperationForChildAckUserWrite(
     return Optional<Operation>(op);
   } else {
     const Tree<bool>* child_tree = op.affected_tree.GetChild(child_key);
-    return Optional<Operation>(Operation::AckUserWrite(
-        Path(), *child_tree, op.revert ? kAckRevert : kAckConfirm));
+    return Optional<Operation>(
+        Operation::AckUserWrite(Path(), child_tree ? *child_tree : Tree<bool>(),
+                                op.revert ? kAckRevert : kAckConfirm));
   }
 }
 

Original file line number	Diff line number	Diff line change
`@@ -118,8 +118,9 @@ static Optional<Operation> OperationForChildAckUserWrite(`
`118`	`118`	`return Optional<Operation>(op);`
`119`	`119`	`} else {`
`120`	`120`	`const Tree<bool>* child_tree = op.affected_tree.GetChild(child_key);`
`121`		`- return Optional<Operation>(Operation::AckUserWrite(`
`122`		`- Path(), *child_tree, op.revert ? kAckRevert : kAckConfirm));`
	`121`	`+ return Optional<Operation>(`
	`122`	`+ Operation::AckUserWrite(Path(), child_tree ? *child_tree : Tree<bool>(),`
	`123`	`+ op.revert ? kAckRevert : kAckConfirm));`
`123`	`124`	`}`
`124`	`125`	`}`
`125`	`126`