Bug: Intermittent browser/components/sessionstore/test/browser_687710_2.js | Uncaught exception - at chrome://mochitests/content/browser/browser/components/sessionstore/test/browser_687710_2.js:62 - TypeError: docShell.sessionHistory is undefined
Status: RESOLVED
Priority: P5
Resolution: INCOMPLETE
Created: 2020-10-03 17:25:34+00:00
Resolved: 2020-10-27 17:05:37+00:00

**Filed by:** btara [at] mozilla.com
**Parsed log:** https://treeherder.mozilla.org/logviewer.html#?job_id=317413098&repo=mozilla-beta
**Full log:** https://firefox-ci-tc.services.mozilla.com/api/queue/v1/task/eDT_WnUoTQeA4YbSL82nNQ/runs/0/artifacts/public/logs/live_backing.log

---
```
```
[task 2020-10-02T16:56:19.076Z] 16:56:19     INFO - TEST-START | browser/components/sessionstore/test/browser_687710_2.js
[task 2020-10-02T16:56:19.092Z] 16:56:19     INFO - GECKO(3163) | [Child 3419, Main Thread] WARNING: NS_ENSURE_TRUE(mDocShell) failed: file /builds/worker/checkouts/gecko/toolkit/components/browser/nsWebBrowser.cpp, line 544
[task 2020-10-02T16:56:19.128Z] 16:56:19     INFO - GECKO(3163) | [Child 3465: Main Thread]: I/DocShellAndDOMWindowLeak ++DOCSHELL 0x7effbc975c00 == 1 [pid = 3465] [id = {e48cd627-944f-4163-a210-b4b6b28e1d2b}]
[task 2020-10-02T16:56:19.129Z] 16:56:19     INFO - GECKO(3163) | [Child 3465: Main Thread]: I/DocShellAndDOMWindowLeak ++DOMWINDOW == 2 (0x7effda18d180) [pid = 3465] [serial = 170] [outer = (nil)]
[task 2020-10-02T16:56:19.129Z] 16:56:19     INFO - GECKO(3163) | [Child 3465: Main Thread]: I/DocShellAndDOMWindowLeak ++DOMWINDOW == 3 (0x7effbc976c00) [pid = 3465] [serial = 171] [outer = 0x7effda18d180]
[task 2020-10-02T16:56:19.186Z] 16:56:19     INFO - GECKO(3163) | [Child 3599: Main Thread]: I/DocShellAndDOMWindowLeak --DOMWINDOW == 0 (0x7efec43b9400) [pid = 3599] [serial = 44] [outer = (nil)] [url = http://example.com/#4]
[task 2020-10-02T16:56:19.307Z] 16:56:19     INFO - GECKO(3163) | [Child 3465: Main Thread]: I/DocShellAndDOMWindowLeak ++DOMWINDOW == 4 (0x7effbcbd5400) [pid = 3465] [serial = 172] [outer = 0x7effda18d180]
[task 2020-10-02T16:56:20.755Z] 16:56:20     INFO - GECKO(3163) | [Child 3465: Main Thread]: I/DocShellAndDOMWindowLeak --DOMWINDOW == 3 (0x7effbcbcd800) [pid = 3465] [serial = 169] [outer = (nil)] [url = about:blank]
[task 2020-10-02T16:56:21.620Z] 16:56:21     INFO - GECKO(3163) | [Child 3546: Main Thread]: I/DocShellAndDOMWindowLeak --DOMWINDOW == 0 (0x7fc9a86d3800) [pid = 3546] [serial = 49] [outer = (nil)] [url = about:blank]
[task 2020-10-02T16:56:21.917Z] 16:56:21     INFO - GECKO(3163) | [Child 3394: Main Thread]: I/DocShellAndDOMWindowLeak --DOMWINDOW == 2 (0x7f97f121cc00) [pid = 3394] [serial = 79] [outer = (nil)] [url = about:blank]
[task 2020-10-02T16:56:22.135Z] 16:56:22     INFO - GECKO(3163) | [Child 3419: Main Thread]: I/DocShellAndDOMWindowLeak --DOMWINDOW == 12 (0x7fec9f612400) [pid = 3419] [serial = 184] [outer = (nil)] [url = about:blank]
[task 2020-10-02T16:56:22.137Z] 16:56:22     INFO - GECKO(3163) | [Child 3419: Main Thread]: I/DocShellAndDOMWindowLeak --DOMWINDOW == 11 (0x7fec9f610800) [pid = 3419] [serial = 182] [outer = (nil)] [url = about:blank]
[task 2020-10-02T16:56:22.137Z] 16:56:22     INFO - GECKO(3163) | [Child 3419: Main Thread]: I/DocShellAndDOMWindowLeak --DOCSHELL 0x7fec9f610000 == 2 [pid = 3419] [id = {ca86d846-b621-43b0-8b72-a5f72a9ebfa7}] [url = about:blank]
[task 2020-10-02T16:56:22.137Z] 16:56:22     INFO - GECKO(3163) | [Child 3419: Main Thread]: I/DocShellAndDOMWindowLeak --DOCSHELL 0x7fec9f60dc00 == 1 [pid = 3419] [id = {2a8bf9eb-7fe2-4ffc-b539-92db89baf15e}] [url = about:blank]
[task 2020-10-02T16:56:22.137Z] 16:56:22     INFO - GECKO(3163) | [Child 3419: Main Thread]: I/DocShellAndDOMWindowLeak --DOCSHELL 0x7fec9f613800 == 0 [pid = 3419] [id = {37301191-e7ca-4c52-a0ba-226dac7565d2}] [url = about:blank]
[task 2020-10-02T16:56:22.212Z] 16:56:22     INFO - GECKO(3163) | [Child 3419: Main Thread]: I/DocShellAndDOMWindowLeak --DOMWINDOW == 10 (0x7fecbcd8da90) [pid = 3419] [serial = 185] [outer = (nil)] [url = about:blank]
[task 2020-10-02T16:56:22.213Z] 16:56:22     INFO - GECKO(3163) | [Child 3419: Main Thread]: I/DocShellAndDOMWindowLeak --DOMWINDOW == 9 (0x7fecbcd8d180) [pid = 3419] [serial = 187] [outer = (nil)] [url = about:blank]
[task 2020-10-02T16:56:22.802Z] 16:56:22     INFO - GECKO(3163) | [Child 3315: Main Thread]: I/DocShellAndDOMWindowLeak --DOMWINDOW == 9 (0x7f0629772c00) [pid = 3315] [serial = 280] [outer = (nil)] [url = about:blank]
[task 2020-10-02T16:56:22.803Z] 16:56:22     INFO - GECKO(3163) | [Child 3315: Main Thread]: I/DocShellAndDOMWindowLeak --DOMWINDOW == 8 (0x7f0629778000) [pid = 3315] [serial = 278] [outer = (nil)] [url = about:blank]
[task 2020-10-02T16:56:22.803Z] 16:56:22     INFO - GECKO(3163) | [Child 3315: Main Thread]: I/DocShellAndDOMWindowLeak --DOCSHELL 0x7f062976e400 == 3 [pid = 3315] [id = {d967f1dc-550e-43d2-a1e8-69d6a34cfe9b}] [url = about:blank]
[task 2020-10-02T16:56:22.803Z] 16:56:22     INFO - GECKO(3163) | [Child 3315: Main Thread]: I/DocShellAndDOMWindowLeak --DOCSHELL 0x7f062976ec00 == 2 [pid = 3315] [id = {bc4ed1b4-6770-434f-aa79-99fd57dea252}] [url = about:blank]
[task 2020-10-02T16:56:22.803Z] 16:56:22     INFO - GECKO(3163) | [Child 3315: Main Thread]: I/DocShellAndDOMWindowLeak --DOCSHELL 0x7f0629770c00 == 1 [pid = 3315] [id = {e95a2d28-c902-4de8-a9ce-3e89c76e0efa}] [url = about:blank]
[task 2020-10-02T16:56:22.863Z] 16:56:22     INFO - GECKO(3163) | [Child 3315: Main Thread]: I/DocShellAndDOMWindowLeak --DOMWINDOW == 7 (0x7f064738d180) [pid = 3315] [serial = 281] [outer = (nil)] [url = about:blank]
[task 2020-10-02T16:56:24.819Z] 16:56:24     INFO - GECKO(3163) | [Child 3465: Main Thread]: I/DocShellAndDOMWindowLeak --DOMWINDOW == 2 (0x7effbc976c00) [pid = 3465] [serial = 171] [outer = (nil)] [url = about:blank]
[task 2020-10-02T16:56:24.829Z] 16:56:24     INFO - TEST-INFO | started process screentopng
[task 2020-10-02T16:56:25.157Z] 16:56:25     INFO - TEST-INFO | screentopng: exit 0
[task 2020-10-02T16:56:25.157Z] 16:56:25     INFO - Buffered messages logged at 16:56:19
[task 2020-10-02T16:56:25.157Z] 16:56:25     INFO - Entering test bound test
[task 2020-10-02T16:56:25.157Z] 16:56:25     INFO - Buffered messages finished
[task 2020-10-02T16:56:25.157Z] 16:56:25     INFO - TEST-UNEXPECTED-FAIL | browser/components/sessionstore/test/browser_687710_2.js | Uncaught exception - at chrome://mochitests/content/browser/browser/components/sessionstore/test/browser_687710_2.js:62 - TypeError: docShell.sessionHistory is undefined
[task 2020-10-02T16:56:25.157Z] 16:56:25     INFO - Stack trace:
[task 2020-10-02T16:56:25.157Z] 16:56:25     INFO - @chrome://mochitests/content/browser/browser/components/sessionstore/test/browser_687710_2.js:62:21
[task 2020-10-02T16:56:25.157Z] 16:56:25     INFO - execute@resource://specialpowers/SpecialPowersSandbox.jsm:141:12
[task 2020-10-02T16:56:25.157Z] 16:56:25     INFO - _spawnTask@resource://specialpowers/SpecialPowersChild.jsm:1617:15
[task 2020-10-02T16:56:25.157Z] 16:56:25     INFO - receiveMessage@resource://specialpowers/SpecialPowersChild.jsm:310:21
[task 2020-10-02T16:56:25.157Z] 16:56:25     INFO - Leaving test bound test
[task 2020-10-02T16:56:25.157Z] 16:56:25     INFO - GECKO(3163) | MEMORY STAT | vsize 3666MB | residentFast 744MB | heapAllocated 349MB
[task 2020-10-02T16:56:25.157Z] 16:56:25     INFO - TEST-OK | browser/components/sessionstore/test/browser_687710_2.js | took 5781ms
[task 2020-10-02T16:56:25.157Z] 16:56:25     INFO - Not taking screenshot here: see the one that was previously logged
[task 2020-10-02T16:56:25.157Z] 16:56:25     INFO - TEST-UNEXPECTED-FAIL | browser/components/sessionstore/test/browser_687710_2.js | Found an unexpected tab at the end of test run: http://example.com/?1#a - 
[task 2020-10-02T16:56:25.157Z] 16:56:25     INFO - GECKO(3163) | [Child 3419: Main Thread]: I/DocShellAndDOMWindowLeak ++DOCSHELL 0x7fec9f60f800 == 1 [pid = 3419] [id = {07ab1f40-8e96-43be-baa3-40cd174a4571}]
[task 2020-10-02T16:56:25.157Z] 16:56:25     INFO - GECKO(3163) | [Child 3419: Main Thread]: I/DocShellAndDOMWindowLeak ++DOMWINDOW == 10 (0x7fecbcd8d180) [pid = 3419] [serial = 196] [outer = (nil)]
[task 2020-10-02T16:56:25.157Z] 16:56:25     INFO - GECKO(3163) | [Child 3419: Main Thread]: I/DocShellAndDOMWindowLeak ++DOMWINDOW == 11 (0x7fec9f612000) [pid = 3419] [serial = 197] [outer = 0x7fecbcd8d180]
[task 2020-10-02T16:56:25.157Z] 16:56:25     INFO - checking window state
``````