tor-browser

commit f2439f05ebfa066c53f087425e3993f109e88f0d
parent 7ece905033de5cfa2b696c3af6983f7d110eee37
Author: Jens Stutte <jstutte@mozilla.com>
Date:   Tue, 25 Nov 2025 20:44:08 +0000

Bug 1991834 - Add a diagnostic error to nsMaybeWeakPtrArray::AppendWeakElement to avoid double adding. r=xpcom-reviewers,mccr8,Gijs

Differential Revision: https://phabricator.services.mozilla.com/D267527

Diffstat:
M
xpcom/base/nsMaybeWeakPtr.h
 | 
10
++++++++++

1 file changed, 10 insertions(+), 0 deletions(-)
diff --git a/xpcom/base/nsMaybeWeakPtr.h b/xpcom/base/nsMaybeWeakPtr.h
@@ -11,6 +11,7 @@
 #include "nsIWeakReferenceUtils.h"
 #include "nsTArray.h"
 #include "nsCycleCollectionNoteChild.h"
+#include "xpcpublic.h"
 
 // nsMaybeWeakPtr is a helper object to hold a strong-or-weak reference
 // to the template class.  It's pretty minimal, but sufficient.
@@ -81,6 +82,15 @@ class nsMaybeWeakPtrArray : public CopyableTArray<nsMaybeWeakPtr<T>> {
     nsMaybeWeakPtr<T> ref;
     MOZ_TRY(SetMaybeWeakPtr(ref, aElement, aOwnsWeak));
 
+#if (defined(MOZ_DIAGNOSTIC_ASSERT_ENABLED) && !defined(MOZ_THUNDERBIRD))
+    // Checking for duplicates is expensive, so we enforce callers to avoid
+    // this with a diagnostic assertion. See bug 2000788 for Thunderbird.
+    if (MaybeWeakArray::Contains(aElement)) {
+      xpc_DumpJSStack(true, true, false);
+      MOZ_DIAGNOSTIC_ASSERT(false, "Element already in array.");
+    }
+#endif
+
     MaybeWeakArray::AppendElement(ref);
     return NS_OK;
   }