Bug: Intermittent remote/shared/test/browser/browser_TabManager.js | Uncaught exception in test - at chrome://browser/content/tabbrowser.js:3763 - TypeError: can't access property "closing", aTab is undefined
Status: RESOLVED
Priority: P5
Resolution: DUPLICATE
Created: 2022-05-02 06:37:50+00:00
Resolved: 2022-07-26 00:17:41+00:00

**Filed by:** ccozmuta [at] mozilla.com
**Parsed log:** https://treeherder.mozilla.org/logviewer?job_id=376432633&repo=autoland
**Full log:** https://firefox-ci-tc.services.mozilla.com/api/queue/v1/task/UI6y-pNiT5yFn9YH-x83pQ/runs/0/artifacts/public/logs/live_backing.log

---
```
[task 2022-05-02T06:21:17.096Z] 06:21:17     INFO - TEST-START | remote/shared/test/browser/browser_TabManager.js
[task 2022-05-02T06:21:17.307Z] 06:21:17     INFO - TEST-INFO | started process screentopng
[task 2022-05-02T06:21:17.629Z] 06:21:17     INFO - TEST-INFO | screentopng: exit 0
[task 2022-05-02T06:21:17.630Z] 06:21:17     INFO - Buffered messages logged at 06:21:17
[task 2022-05-02T06:21:17.631Z] 06:21:17     INFO - Entering test bound test_getBrowsingContextById
[task 2022-05-02T06:21:17.632Z] 06:21:17     INFO - TEST-PASS | remote/shared/test/browser/browser_TabManager.js | undefined assertion name - 
[task 2022-05-02T06:21:17.633Z] 06:21:17     INFO - TEST-PASS | remote/shared/test/browser/browser_TabManager.js | undefined assertion name - 
[task 2022-05-02T06:21:17.633Z] 06:21:17     INFO - TEST-PASS | remote/shared/test/browser/browser_TabManager.js | undefined assertion name - 
[task 2022-05-02T06:21:17.634Z] 06:21:17     INFO - Navigate to https://example.com/document-builder.sjs?html=%3Ciframe%20src=%22https://example.com/document-builder.sjs?html=frame%22%3E%3C/iframe%3E
[task 2022-05-02T06:21:17.637Z] 06:21:17     INFO - Console message: [JavaScript Warning: "This page is in Quirks Mode. Page layout may be impacted. For Standards Mode use “<!DOCTYPE html>”." {file: "https://example.com/document-builder.sjs?html=%3Ciframe%20src=%22https://example.com/document-builder.sjs?html=frame%22%3E%3C/iframe%3E" line: 0}]
[task 2022-05-02T06:21:17.637Z] 06:21:17     INFO - Console message: [JavaScript Warning: "This page is in Quirks Mode. Page layout may be impacted. For Standards Mode use “<!DOCTYPE html>”." {file: "https://example.com/document-builder.sjs?html=frame" line: 0}]
[task 2022-05-02T06:21:17.637Z] 06:21:17     INFO - Console message: [JavaScript Warning: "The character encoding of a framed document was not declared. The document may appear different if viewed without the document framing it." {file: "https://example.com/document-builder.sjs?html=frame" line: 0}]
[task 2022-05-02T06:21:17.637Z] 06:21:17     INFO - TEST-PASS | remote/shared/test/browser/browser_TabManager.js | Top context has 1 child - 
[task 2022-05-02T06:21:17.637Z] 06:21:17     INFO - TEST-PASS | remote/shared/test/browser/browser_TabManager.js | undefined assertion name - 
[task 2022-05-02T06:21:17.638Z] 06:21:17     INFO - TEST-PASS | remote/shared/test/browser/browser_TabManager.js | undefined assertion name - 
[task 2022-05-02T06:21:17.639Z] 06:21:17     INFO - Leaving test bound test_getBrowsingContextById
[task 2022-05-02T06:21:17.639Z] 06:21:17     INFO - Entering test bound test_addTab_focus
[task 2022-05-02T06:21:17.640Z] 06:21:17     INFO - Buffered messages finished
[task 2022-05-02T06:21:17.641Z] 06:21:17     INFO - TEST-UNEXPECTED-FAIL | remote/shared/test/browser/browser_TabManager.js | Uncaught exception in test - at chrome://browser/content/tabbrowser.js:3763 - TypeError: can't access property "closing", aTab is undefined
[task 2022-05-02T06:21:17.641Z] 06:21:17     INFO - Stack trace:
[task 2022-05-02T06:21:17.642Z] 06:21:17     INFO - removeTab@chrome://browser/content/tabbrowser.js:3763:11
[task 2022-05-02T06:21:17.642Z] 06:21:17     INFO - test_addTab_focus@chrome://mochitests/content/browser/remote/shared/test/browser/browser_TabManager.js:68:14
[task 2022-05-02T06:21:17.642Z] 06:21:17     INFO - handleTask@chrome://mochikit/content/browser-test.js:989:26
[task 2022-05-02T06:21:17.643Z] 06:21:17     INFO - _runTaskBasedTest@chrome://mochikit/content/browser-test.js:1061:18
[task 2022-05-02T06:21:17.643Z] 06:21:17     INFO - Leaving test bound test_addTab_focus
[task 2022-05-02T06:21:17.645Z] 06:21:17     INFO - Entering test bound test_addTab_window
[task 2022-05-02T06:21:22.295Z] 06:21:22     INFO - TEST-PASS | remote/shared/test/browser/browser_TabManager.js | undefined assertion name - 
[task 2022-05-02T06:21:22.308Z] 06:21:22     INFO - TEST-PASS | remote/shared/test/browser/browser_TabManager.js | The new tab was opened in the specified window - 
[task 2022-05-02T06:21:22.347Z] 06:21:22     INFO - TEST-PASS | remote/shared/test/browser/browser_TabManager.js | The new tab was opened in the specified window - 
[task 2022-05-02T06:21:22.395Z] 06:21:22     INFO - TEST-PASS | remote/shared/test/browser/browser_TabManager.js | The new tab was opened in the foreground window - 
[task 2022-05-02T06:21:22.683Z] 06:21:22     INFO - Console message: [JavaScript Error: "Cannot attach ID to a tab in a closed window." {file: "chrome://browser/content/parent/ext-browser.js" line: 369}]
[task 2022-05-02T06:21:22.684Z] 06:21:22     INFO - setId@chrome://browser/content/parent/ext-browser.js:369:13
[task 2022-05-02T06:21:22.684Z] 06:21:22     INFO - getId@chrome://browser/content/parent/ext-browser.js:345:10
[task 2022-05-02T06:21:22.684Z] 06:21:22     INFO - wrapTab@chrome://browser/content/parent/ext-browser.js:1188:58
[task 2022-05-02T06:21:22.684Z] 06:21:22     INFO - statusListener@chrome://browser/content/parent/ext-tabs.js:504:33
```