1494933 - Debugging extension after removing AMO version fails with "item is null"

Status: RESOLVED DUPLICATE of bug 1541317

(WebExtensions :: Developer Tools, defect, P3)

Description

[Thomas Werner]

Attachment: Screenshot 2018-09-28 at 13.13.52.png

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:62.0) Gecko/20100101 Firefox/62.0
Build ID: 20180920131237

Steps to reproduce:

1) Install an extension from AMO where you own the source code for development
2) Extension is working (after several restarts too)
3) Remove extension w/o quitting/restarting Firefox
4) Debug "same" extension by adding local source


Actual results:

"There was an error during installation: item is null"


Expected results:

Should be able to debug/develop extension without (several) restarts.

Comment 1

[Luca Greco [:rpl] [:luca] [:lgreco]]

Hi Thomas,
I'm currently unable to reproduce this issue locally, but I still suspect that there may be something that I'm missing in the "steps to reproduce" from comment 0.

Do you mind to take a look in the Browser Console to see if the "item is null" error is also logged there? 
in the Browser Console the error should also include a stacktrace that may help us to identify what is triggering it and how to reproduce it locally.

Is the issue happening for you on any extension or is it triggered only by some extensions?
if it is possible, it would be great to have the name/id of one extension which consistently triggered this issue for you.

(e.g. I'm wondering if, to be able to reproduce the issue, the extension has to make use of a particular feature/API,
as an example "extensions with chrome settings override" or "extensions which has the property X in their manifest".

Comment 2

[Thomas Werner]

Hi Luca,

sorry for delay... 

Something changed, it does not happen anymore after step 4. But if i remove the debugged extension and re-add it again then i get the same error.

1) Install an extension from AMO where you own the source code for development
2) Extension is working (after several restarts too)
3) Remove extension w/o quitting/restarting Firefox
4) Debug "same" extension by adding local source
5) Removing debug extension again w/o quitting/restarting Firefox
6) Re-add "same" extension for debugging

TypeError: "item is null"
onManifestEntry chrome://browser/content/parent/ext-chrome-settings-overrides.js:194:9
installAddon resource://devtools/client/aboutdebugging/components/addons/Controls.js:85:9

Maybe something different => "TypeError: can't access dead object (accessible.js:128:5)" 
resource://devtools/server/actors/highlighters/accessible.js

And you're right, for debugging the extension i use the manifest file used for Chrome as well, which contains nodes like "version_name". But in past i did not care because for debugging it was never be a problem having such warnings. I have a script which corrects the entries, but on making a "release" only.

Please let me know if you need still the source code with "malformed" manifest file for testing, i can send you it to your email address or give you access to GIT.

https://addons.mozilla.org/en-US/firefox/addon/nellitab/

Comment 3

[Thomas Werner]

Because of ext-chrome-settings-overrides.js:194:9 maybe the following is useful. Node "homepage_override" is only in the AMO version, but not in the manifest for debugging. 

My script/Makefile adds it on making release only otherwise my source code would not work in Chrome for testing (i guess, i forgot). But still strange, why its working on first "try"...

Anyway, if this the reason, i do not want to wast your time, its really not important. =)

Comment 4

[Luca Greco [:rpl] [:luca] [:lgreco]]

Hi Thomas,
the TypeError: "item is null" error raised from ext-chrome-settings-overrides.js mentioned in this issue should have been fixed by Bug 1541317, which has been uplifted to Firefox 67 and so this issue should be not be reproducible anymore on Firefox >= 67.

I gave it a quick try and I was able to trigger the error on Firefox 66 but not on Firefox 67.

Would you mind to give it a try and confirm that you are also unable to reproduce it on Firefox 67?

Comment 6

[Thomas Werner]

Works for me know.