TypeError: can't access dead object Stack trace: WalkerActor<.querySelector<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/server/actors/inspector.js:1727:9 actorProto/</handler@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/server/protocol.js:1004:19 DSC_onPacket@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/server/main.js:1485:15 LocalDebuggerTransport.prototype.send/<@resource://gre/modules/devtools/dbg-client.jsm -> resource://gre/modules/devtools/transport/transport.js:545:11 makeInfallible/<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/DevToolsUtils.js:83:14 makeInfallible/<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/DevToolsUtils.js:83:14

I shoulder surfed this - it doesn't seem like it is re;lated to navigation or e10s. shobson is running Beta.

I can reliably reproduce the blank console by opening the inspector, picking the tool and hovering over things to display the box model colours, then, without actually clicking on an element, refreshing the page BUT this only reliably works on the page I'm currently working on AND not on the production version of that site. If I open the browser console, clear the errors and then duplicate the steps to reproduce this is the browser console outputs the following information: TypeError: can't access dead object highlighter.js:693:8 TypeError: this.inherited.tagName is null Stack trace: Rule.prototype.inheritedSource@resource://gre/modules/commonjs/toolkit/loader.js -> resource:///modules/devtools/styleinspector/rule-view.js:463:11 CssRuleView.prototype._createEditors@resource://gre/modules/commonjs/toolkit/loader.js -> resource:///modules/devtools/styleinspector/rule-view.js:1770:11 CssRuleView.prototype._populate/<@resource://gre/modules/commonjs/toolkit/loader.js -> resource:///modules/devtools/styleinspector/rule-view.js:1591:7 Handler.prototype.process@resource://gre/modules/Promise.jsm -> resource://gre/modules/Promise-backend.js:870:23 this.PromiseWalker.walkerLoop@resource://gre/modules/Promise.jsm -> resource://gre/modules/Promise-backend.js:749:7 this.PromiseWalker.scheduleWalkerLoop/<@resource://gre/modules/Promise.jsm -> resource://gre/modules/Promise-backend.js:691:37 rule-view.js:46 TypeError: this.inherited.tagName is null Stack trace: Rule.prototype.inheritedSource@resource://gre/modules/commonjs/toolkit/loader.js -> resource:///modules/devtools/styleinspector/rule-view.js:463:11 CssRuleView.prototype._createEditors@resource://gre/modules/commonjs/toolkit/loader.js -> resource:///modules/devtools/styleinspector/rule-view.js:1770:11 CssRuleView.prototype._populate/<@resource://gre/modules/commonjs/toolkit/loader.js -> resource:///modules/devtools/styleinspector/rule-view.js:1591:7 Handler.prototype.process@resource://gre/modules/Promise.jsm -> resource://gre/modules/Promise-backend.js:870:23 this.PromiseWalker.walkerLoop@resource://gre/modules/Promise.jsm -> resource://gre/modules/Promise-backend.js:749:7 this.PromiseWalker.scheduleWalkerLoop/<@resource://gre/modules/Promise.jsm -> resource://gre/modules/Promise-backend.js:691:37 Promise-backend.js:873 TypeError: can't access dead object highlighter.js:693:8 console.trace(): inspector.js:2875 exports.WalkerFront<.getMutations</<() inspector.js:2875 resolve() deprecated-sync-thenables.js:40 then() deprecated-sync-thenables.js:20 resolve() deprecated-sync-thenables.js:72 resolve() deprecated-sync-thenables.js:40 then() deprecated-sync-thenables.js:20 resolve() deprecated-sync-thenables.js:72 resolve() deprecated-sync-thenables.js:40 then() deprecated-sync-thenables.js:20 resolve() deprecated-sync-thenables.js:72 Front<.onPacket() protocol.js:1208 DebuggerClient.prototype.onPacket() dbg-client.jsm:890 LocalDebuggerTransport.prototype.send/<() transport.js:545 makeInfallible/<() DevToolsUtils.js:83 makeInfallible/<() DevToolsUtils.js:83 <anonymous>

Stephanie: can you still reproduce this issue? I believe the initial error about highlighter.js was fixed by https://bugzilla.mozilla.org/show_bug.cgi?id=1109112 , but not sure if it was the only reason for the bug.

I can't reproduce but I didn't write down which page I was on so I don't know for sure. Hopefully it was fixed :)

Still happening in 46.0b10 What can I do to help diagnose?

(In reply to Stephanie Hobson [:shobson] from comment #5) > Still happening in 46.0b10 What can I do to help diagnose? We need more accurate STRs to investigate. From what I understood the steps are : - open a webpage (<--- any specific URL we should use?) - open devtools (<--- docked/separate window?) - click on the "Pick an element from the page" tool - move the mouse on elements of the page - reload the page (<--- while moving the mouse on elements? using CTRL+R, F5 ?) Trying this on various webpages, I can't reproduce the issue. Can you have a look at the steps I listed, and let us know if we missed something. Did you try with a clean profile as well ? Thanks!

- open a webpage (<--- any specific URL we should use?) So far it has only happened to me when developing locally. One of the environments is served from localhost and the other is a vagrant VM with a full URL. (This is where I do most of my dev work, I'm not sure we should read anything into this) - open devtools (<--- docked/separate window?) Docked - reload the page (<--- while moving the mouse on elements? using CTRL+R, F5 ?) CMD+SHIFT+R is what I do most often but I'm not sure what I've done in the specific instances it's been triggered I have not tried a clean profile. It doesn't happen 100% of the time but once I trigger it I can trigger it again following those steps. It's possible there is something else necessary to trigger it the first time.

Inspector bug triage (filter on CLIMBING SHOES). This should really be a P1, but since it seems really hard to reproduce and doesn't always happen, flagging as a P2 for now.

I think I've found another way to replicate this behaviour... or another bug. 1) open a page 2) open element inspector and inspect something 3) shut down your localhost server 4) refresh the page 5) get "Unable to connect" error page (element inspector is empty) 6) restart lcoalhost sever 7) refresh the page 8) element inspector is still empty 9) try inspecting an element, element inspector stays empty

(In reply to Stephanie Hobson [:shobson] from comment #9) > I think I've found another way to replicate this behaviour... or another bug. > This is Bug 983386. After navigating from an error or "special" page, the inspector is very likely to be blank. Since your STRs mention reloading a page, I think these are 2 separate issues.

Stephanie, would you mind telling us if you still face these issues while testing on Firefox Nightly? ( http://nightly.mozilla.org/ ) We recently landed various fixes in the inspector preventing it from being broken. It would be good to know if we missed something.

My dev environment is currently broken and I'm about to go on 7 weeks of leave. So I can't help with testing, sorry. Feel free to close the bug if you think you've fixed it.

We were told that we could close this two years ago.