Bug: Intermittent browser/base/content/test/general/browser_bug763468_perwindowpb.js | A promise chain failed to handle a rejection: (Unable to convert rejection reason to string.) - stack: (No stack available.)
Status: RESOLVED
Priority: P5
Resolution: FIXED
Created: 2020-10-24 02:15:59+00:00
Resolved: 2021-01-11 17:47:16+00:00

**Filed by:** btara [at] mozilla.com
**Parsed log:** https://treeherder.mozilla.org/logviewer.html#?job_id=319617944&repo=autoland
**Full log:** https://firefox-ci-tc.services.mozilla.com/api/queue/v1/task/YxnZDPWrRqaiiOynqmyzIg/runs/0/artifacts/public/logs/live_backing.log

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```
...
[task 2020-10-24T01:50:57.940Z] 01:50:57     INFO - GECKO(1505) | [Child 1658: Main Thread]: I/DocShellAndDOMWindowLeak ++DOMWINDOW == 15 (0x7f4ec398d000) [pid = 1658] [serial = 36] [outer = 0x7f4ec77c2200]
[task 2020-10-24T01:50:58.056Z] 01:50:58     INFO - GECKO(1505) | [Parent 1505, Main Thread] WARNING: Wrong button set to eContextMenu event?: 'mMessage != eContextMenu || (mButton == ((mContextMenuTrigger == eNormal) ? MouseButton::eSecondary : MouseButton::ePrimary) && (mContextMenuTrigger != eControlClick || IsControl()))', file /builds/worker/workspace/obj-build/dist/include/mozilla/MouseEvents.h:244
[task 2020-10-24T01:50:58.056Z] 01:50:58     INFO - GECKO(1505) | [Parent 1505, Main Thread] WARNING: Wrong button set to eContextMenu event?: 'mMessage != eContextMenu || (mButton == ((mContextMenuTrigger == eNormal) ? MouseButton::eSecondary : MouseButton::ePrimary) && (mContextMenuTrigger != eControlClick || IsControl()))', file /builds/worker/workspace/obj-build/dist/include/mozilla/MouseEvents.h:244
[task 2020-10-24T01:50:58.486Z] 01:50:58     INFO - GECKO(1505) | [Child 1658: Main Thread]: I/DocShellAndDOMWindowLeak ++DOMWINDOW == 16 (0x7f4ec40eb800) [pid = 1658] [serial = 37] [outer = 0x7f4ec6eeb040]
[task 2020-10-24T01:50:58.591Z] 01:50:58     INFO - GECKO(1505) | JavaScript error: resource:///actors/LightweightThemeChild.jsm, line 38: TypeError: can't access property "docShell", this.contentWindow.top is null
[task 2020-10-24T01:50:58.596Z] 01:50:58     INFO - GECKO(1505) | JavaScript error: resource:///actors/LightweightThemeChild.jsm, line 38: TypeError: can't access property "docShell", this.contentWindow.top is null
[task 2020-10-24T01:50:58.638Z] 01:50:58     INFO - GECKO(1505) | [Child 1658, Main Thread] WARNING: NS_ENSURE_TRUE(!mHasOrHasHadOwnerWindow || mOwnerWindow) failed: file /builds/worker/checkouts/gecko/dom/events/DOMEventTargetHelper.cpp:291
[task 2020-10-24T01:50:58.658Z] 01:50:58     INFO - GECKO(1505) | JavaScript error: , line 0: uncaught exception: undefined
[task 2020-10-24T01:50:59.069Z] 01:50:59     INFO - TEST-INFO | started process screentopng
[task 2020-10-24T01:50:59.317Z] 01:50:59     INFO - TEST-INFO | screentopng: exit 0
[task 2020-10-24T01:50:59.318Z] 01:50:59     INFO - Buffered messages logged at 01:50:52
[task 2020-10-24T01:50:59.318Z] 01:50:59     INFO - Entering test bound testPBNewTab
[task 2020-10-24T01:50:59.319Z] 01:50:59     INFO - Buffered messages logged at 01:50:54
[task 2020-10-24T01:50:59.320Z] 01:50:59     INFO - TEST-PASS | browser/base/content/test/general/browser_bug763468_perwindowpb.js | URL of NewTab should be about:newtab in normal mode - 
[task 2020-10-24T01:50:59.320Z] 01:50:59     INFO - Buffered messages logged at 01:50:56
[task 2020-10-24T01:50:59.321Z] 01:50:59     INFO - TEST-PASS | browser/base/content/test/general/browser_bug763468_perwindowpb.js | URL of NewTab should be about:privatebrowsing in per window private browsing mode - 
[task 2020-10-24T01:50:59.321Z] 01:50:59     INFO - Buffered messages logged at 01:50:58
[task 2020-10-24T01:50:59.322Z] 01:50:59     INFO - TEST-PASS | browser/base/content/test/general/browser_bug763468_perwindowpb.js | URL of NewTab should be about:newtab in normal mode - 
[task 2020-10-24T01:50:59.323Z] 01:50:59     INFO - Leaving test bound testPBNewTab
[task 2020-10-24T01:50:59.323Z] 01:50:59     INFO - Console message: [JavaScript Error: "uncaught exception: undefined"]
[task 2020-10-24T01:50:59.324Z] 01:50:59     INFO - Console message: [JavaScript Error: "TypeError: can't access property "docShell", this.contentWindow.top is null" {file: "resource:///actors/LightweightThemeChild.jsm" line: 38}]
[task 2020-10-24T01:50:59.324Z] 01:50:59     INFO - _getChromeOuterWindowID@resource:///actors/LightweightThemeChild.jsm:38:5
[task 2020-10-24T01:50:59.325Z] 01:50:59     INFO - handleEvent@resource:///actors/LightweightThemeChild.jsm:54:52
[task 2020-10-24T01:50:59.325Z] 01:50:59     INFO - 
[task 2020-10-24T01:50:59.325Z] 01:50:59     INFO - Console message: [JavaScript Error: "TypeError: can't access property "docShell", this.contentWindow.top is null" {file: "resource:///actors/LightweightThemeChild.jsm" line: 38}]
[task 2020-10-24T01:50:59.326Z] 01:50:59     INFO - _getChromeOuterWindowID@resource:///actors/LightweightThemeChild.jsm:38:5
[task 2020-10-24T01:50:59.326Z] 01:50:59     INFO - handleEvent@resource:///actors/LightweightThemeChild.jsm:54:52
[task 2020-10-24T01:50:59.327Z] 01:50:59     INFO - 
[task 2020-10-24T01:50:59.327Z] 01:50:59     INFO - Buffered messages finished
[task 2020-10-24T01:50:59.328Z] 01:50:59     INFO - TEST-UNEXPECTED-FAIL | browser/base/content/test/general/browser_bug763468_perwindowpb.js | A promise chain failed to handle a rejection: (Unable to convert rejection reason to string.) - stack: (No stack available.)
[task 2020-10-24T01:50:59.328Z] 01:50:59     INFO - Rejection date: Sat Oct 24 2020 01:50:58 GMT+0000 (Coordinated Universal Time) - false == true - JS frame :: resource://testing-common/PromiseTestUtils.jsm :: assertNoUncaughtRejections :: line 265
[task 2020-10-24T01:50:59.329Z] 01:50:59     INFO - Stack trace:
[task 2020-10-24T01:50:59.329Z] 01:50:59     INFO - resource://testing-common/PromiseTestUtils.jsm:assertNoUncaughtRejections:265
[task 2020-10-24T01:50:59.329Z] 01:50:59     INFO - chrome://mochikit/content/browser-test.js:nextTest:615
[task 2020-10-24T01:50:59.330Z] 01:50:59     INFO - GECKO(1505) | JavaScript error: resource:///actors/LightweightThemeChild.jsm, line 38: TypeError: can't access property "docShell", this.contentWindow.top is null
[task 2020-10-24T01:50:59.331Z] 01:50:59     INFO - GECKO(1505) | JavaScript error: resource:///actors/LightweightThemeChild.jsm, line 38: TypeError: can't access property "docShell", this.contentWindow.top is null
[task 2020-10-24T01:50:59.331Z] 01:50:59     INFO - GECKO(1505) | [Child 1658, Main Thread] WARNING: NS_ENSURE_TRUE(!mHasOrHasHadOwnerWindow || mOwnerWindow) failed: file /builds/worker/checkouts/gecko/dom/events/DOMEventTargetHelper.cpp:291
[task 2020-10-24T01:50:59.332Z] 01:50:59     INFO - GECKO(1505) | [Child 1658, Main Thread] WARNING: NS_ENSURE_TRUE(!mHasOrHasHadOwnerWindow || mOwnerWindow) failed: file /builds/worker/checkouts/gecko/dom/events/DOMEventTargetHelper.cpp:291
[task 2020-10-24T01:50:59.332Z] 01:50:59     INFO - Console message: [JavaScript Error: "TypeError: can't access property "docShell", this.contentWindow.top is null" {file: "resource:///actors/LightweightThemeChild.jsm" line: 38}]
[task 2020-10-24T01:50:59.333Z] 01:50:59     INFO - _getChromeOuterWindowID@resource:///actors/LightweightThemeChild.jsm:38:5
[task 2020-10-24T01:50:59.333Z] 01:50:59     INFO - handleEvent@resource:///actors/LightweightThemeChild.jsm:54:52
[task 2020-10-24T01:50:59.334Z] 01:50:59     INFO - 
[task 2020-10-24T01:50:59.336Z] 01:50:59     INFO - Console message: [JavaScript Error: "TypeError: can't access property "docShell", this.contentWindow.top is null" {file: "resource:///actors/LightweightThemeChild.jsm" line: 38}]
[task 2020-10-24T01:50:59.337Z] 01:50:59     INFO - _getChromeOuterWindowID@resource:///actors/LightweightThemeChild.jsm:38:5
[task 2020-10-24T01:50:59.337Z] 01:50:59     INFO - handleEvent@resource:///actors/LightweightThemeChild.jsm:54:52
[task 2020-10-24T01:50:59.337Z] 01:50:59     INFO - 
[task 2020-10-24T01:50:59.337Z] 01:50:59     INFO - GECKO(1505) | MEMORY STAT | vsize 3503MB | residentFast 457MB | heapAllocated 146MB
[task 2020-10-24T01:50:59.337Z] 01:50:59     INFO - TEST-OK | browser/base/content/test/general/browser_bug763468_perwindowpb.js | took 6751ms
...```