900045 - Opening the debugger after the console or inspector results in: TypeError: can't access dead object

Status: RESOLVED WORKSFORME

(DevTools :: Debugger, defect, P2)

Description

[Panos Astithas (he/him) [:past] (please ni?)]

STR:

1. Open this web page: http://well.blogs.nytimes.com/2013/07/31/how-exercise-changes-fat-and-muscle-cells/?_r=3&
2. Open the web console or the inspector
3. Open the debugger

Some times (more often than not) the debugger displays an empty source list and the Browser Console has the following error:

[18:58:33.172] TypeError: can't access dead object
TA__addDebuggees@resource://gre/modules/devtools/dbg-server.jsm -> resource://gre/modules/devtools/server/actors/script.js:366
TA_findGlobals@resource://gre/modules/devtools/dbg-server.jsm -> resource://gre/modules/devtools/server/actors/script.js:381
TA_onAttach@resource://gre/modules/devtools/dbg-server.jsm -> resource://gre/modules/devtools/server/actors/script.js:450
DSC_onPacket@resource://gre/modules/devtools/dbg-server.jsm -> resource://gre/modules/devtools/server/main.js:914
@resource://gre/modules/devtools/dbg-server.jsm -> resource://gre/modules/devtools/server/transport.js:239
@resource://gre/modules/devtools/dbg-server.jsm -> resource://gre/modules/devtools/DevToolsUtils.js:61
 @ resource://gre/modules/devtools/dbg-server.jsm -> resource://gre/modules/devtools/server/main.js:820

Comment 1

[Mihai Sucan [:msucan]]

I have seen this when playing with the inspector.

Comment 2

[Mihai Sucan [:msucan]]

I was able to reproduce the bug by simply opening the provided URL and open the debugger. You do not need to first open the inspector/console - just open the debugger. Opening other tools seems unrelated.

When I open the debugger no sources show up and I get the following exception:

error occurred while processing 'attach: TypeError: can't access dead object
Stack: TA__addDebuggees@resource://gre/modules/devtools/dbg-server.jsm -> resource://gre/modules/devtools/server/main.js -> resource://gre/modules/devtools/server/actors/script.js:541
TA_findGlobals@resource://gre/modules/devtools/dbg-server.jsm -> resource://gre/modules/devtools/server/main.js -> resource://gre/modules/devtools/server/actors/script.js:556
TA_onAttach@resource://gre/modules/devtools/dbg-server.jsm -> resource://gre/modules/devtools/server/main.js -> resource://gre/modules/devtools/server/actors/script.js:625
...

Having looked a bit into the ThreadActor code, it seems that findGlobals() calls _addDebuggees() with this.global. Maybe this.global is a dead object by the time _addDebuggees() is called.

Comment 3

[Panos Astithas (he/him) [:past] (please ni?)]

This and bug 912924 seem related. I think I have a theory for a fix.

Comment 4

[Panos Astithas (he/him) [:past] (please ni?)]

I haven't been able to reproduce this lately. Not sure what fixed it.