Seen during mochitests on b2g debug emulator builds: https://tbpl.mozilla.org/php/getParsedLog.php?id=32730519&tree=Pine&full=1

Lemme think about this in the morning; this might just be an overzealous assert.

Ah hah, I see it: bug 944821 added a new child/parent roundtrip between the parent and child: parent -OnOpenMetadataForRead-> child -SelectCacheFileToRead-> parent if the child fails to FindHashMatch in RecvOnOpenMetadataForRead, then it will Send__delete__ which causes the parent to Recv__delete__ when the cache file has not yet been opened, hence the assert.

Given the new interleaving described above, the fix is just to generalize Recv__delete__ to be more like ActorDestroy which can happen at any time. I was able to repro the assert on desktop FF with browser.tabs.remote = true on http://people.mozilla.org/~lwagner/test-caching.html and verify that this patch fixes the assert.

Comment on attachment 8357603 [details] [diff] [review] fix-open-bug Review of attachment 8357603 [details] [diff] [review]: ----------------------------------------------------------------- looks good