1388825 - Debugger pane completely empty in the browser toolbox in one of my profiles

Status: RESOLVED DUPLICATE of bug 1391719

(DevTools :: Debugger, defect, P3)

Description

[:Gijs (he/him)]

It works on an empty profile. I would like to know why it's broken on the other one. Stdout/err has:


JavaScript error: resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/client/debugger/new/debugger.js, line 37638: SyntaxError: JSON.parse: bad control character in string literal at line 1 column 428 of the JSON data
console.error: 
  Message: TypeError: this.panelWin.Debugger is undefined
  Stack:
    open@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/client/debugger/new/panel.js:29:1
onLoad@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/client/framework/toolbox.js:1551:19


I don't really know what to make of that.

Comment 1

[Julian Descottes [:jdescottes]]

Attachment: Bug 1388825 - bump debugger model version

Review commit: https://reviewboard.mozilla.org/r/166682/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/166682/

Comment 2

[Julian Descottes [:jdescottes]]

Comment on attachment 8895478 [details]
Bug 1388825 - bump debugger model version

Review request updated; see interdiff: https://reviewboard.mozilla.org/r/166682/diff/1-2/

Comment 3

[Julian Descottes [:jdescottes]]

As discussed on IRC, I suspect this could be another manifestation of Bug 1388128.

The way the profile of the browser toolbox is created is to copy the current profile + override some preferences with custom values. This means that the fix we landed in Bug 1388128 might not easily make its way to the browser toolbox profile. 

A safer way of forcing a breakpoints cleanup is probably to bump the model version expected by the debugger runtime.

Comment 4

[:Gijs (he/him)]

So, it seems this is broken because of this pref containing a saved expression:


      user_pref("devtools.debugger.expressions", "[{\"input\":\"BookmarkingUI.anchor\",\"value\":{\"from\":\"server2.conn0.consoleActor2\",\"input\":\"BookmarkingUI.anchor\",\"result\":{\"type\":\"object\",\"actor\":\"server2.conn0.obj900\",\"class\":\"XULElement\",\"extensible\":true,\"frozen\":false,\"sealed\":false,\"ownPropertyLength\":0,\"preview\":{\"kind\":\"DOMNode\",\"nodeType\":1  ,\"nodeName\":\"image\",\"isConnected\":true,\"attributes\":{\"id\":\"star-button\",\"class\":\"urlbar-icon\",\"tooltiptext\":\"Edit this bookmark (^XD)\",\"preloadanimations\":\"true\",\"anima  te\":\"true\",\"starred\":\"true\"},\"attributesLength\":6}},\"timestamp\":1501764023273,\"exception\":null,\"frame\":null,\"helperResult\":null,\"notes\":null},\"updating\":false,\"visible\":true}]");¬ 


This was copy-pasted from VI so might be slightly mangled, but the gist is:
\"Edit this bookmark (^XD)\"

where ^X will be a control char representing the apple command sign that we use for shortcuts.


Some suggestions:

1) we should probably not save previews of expression values across restarts
2) if loading them from the pref fails, startup should not fail.
3) if we do save things with control chars, we should make sure they get saved in a way that we can re-parse when loading.

Comment 5

[Julian Descottes [:jdescottes]]

In case anyone wants to reproduce, you can follow the STRs below:
- open the browser toolbox
- with the browser toolbox inspector, select the "star" icon inside the URL 
- switch to the browser toolbox debugger, break anywhere
- in the console run "var test = $0"
- add a watch expression on "test"
- quit the browser toolbox 
- restart the browser toolbox -> empty debugger

Comment 6

[Julian Descottes [:jdescottes]]

Much simpler STRs:

- open the debugger
- break anywhere
- evaluate `var test = "⌘"`
- add a watch expression on `test`
- close/reopen the debugger

So for the record, JSON.parse(JSON.stringify("⌘")) works fine of course. Which means that the step creating the bug is when we save it to a pref.

Comment 7

[:Gijs (he/him)]

Maybe using a string pref rather than a char pref would work?

Comment 8

[Julian Descottes [:jdescottes]]

(In reply to :Gijs from comment #7)
> Maybe using a string pref rather than a char pref would work?

Thanks for the suggestion! Just tested locally and it fixes the issue, I will send a PR on GitHub for that.

Comment 9

[Julian Descottes [:jdescottes]]

Ongoing PR in devtools-core: https://github.com/devtools-html/devtools-core/pull/581

Comment 10

[Julian Descottes [:jdescottes]]

PR to devtools-core has been merged. 
Opened a PR for the debugger to get the fix from devtools-core: https://github.com/devtools-html/debugger.html/pull/3620 

After it gets merged, this will be blocked on the next debugger bundle update in m-c.

Comment 11

[Julian Descottes [:jdescottes]]

Both PRs are merged, now waiting for the next debugger update in m-c!

Comment 12

[Julian Descottes [:jdescottes]]

Should be fixed by landing the new debugger bundle which is being updated in Bug 1391719.