Closed Bug 1418798 Opened 7 years ago Closed 5 years ago

Source map is ignored when debugging popup script


(DevTools :: Debugger, defect)

58 Branch
Not set


(Not tracked)



(Reporter: kirill.rakhman, Unassigned, NeedInfo)


(Blocks 1 open bug)


(Whiteboard: needs-review)

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:58.0) Gecko/20100101 Firefox/58.0
Build ID: 20171115114231

Steps to reproduce:

I'm trying to port the extension tutorial from to Kotlin JS. 
You can try out the extension using

The Kotlin code is compiled to Javascript and it contains a comment at the end of the file pointing to the sourcemap in the same directory, e.g.


Actual results:

When debugging the popup script using about:debugging (according to, the source map seems to be ignored and the generated JS code is displayed instead.

When debugging a content script, the source map is however taken into account and displayed correctly.

Expected results:

I expected to see the Kotlin code (using the source map) for the popup script in the addon debugger.
Component: Untriaged → Developer Tools: Debugger
Blocks: source-maps
Product: Firefox → DevTools

Hmm, i'm curious what you think Julian. I'm not too familiar with remote debugging.

Flags: needinfo?(jdescottes)
Whiteboard: needs-review

(In reply to Jason Laster [:jlast] from comment #1)

Hmm, i'm curious what you think Julian. I'm not too familiar with remote debugging.

I think it is not remote debugging, but rather local addon debugging. But I can help you with the STRs :)

1/ Build the extension

  • run git clone
  • cd second-firefox-extension-kotlin
  • ./gradlew runDceKotlinJs

2/ Load the extension

  • start Firefox
  • open about:debugging
  • select "This Firefox" (or This Nightly)
  • click on "Load Temporary Add-on..."
  • open second-firefox-extension-kotlin/manifest.json

3/ Enable "Disable popup auto hide"

  • open the Browser Toolbox
  • turn on "Disable popup auto hide" in the Browser Toolbox hamburger menu
  • (you can close the Browser Toolbox now)

4/ Trigger the extension's popup

  • open any website with images (eg
  • click on the Beastify extension icon in the toolbar
  • this should show the extension's popup with 4 items "Frog, Turtle, Snake, Reset"
  • (and thanks to step 3 the popup should still be displayed)

5/ Debug the extension

  • go back to about:debugging#/runtime/this-firefox
  • in the Temporary Extensions category, click on Inspect next to Beastify
  • open the debugger
  • check if sourcemapped sources are working

Note that it seems to work a bit better than what the initial report mentioned. I can see *.kt files in the source tree. Some can be opened (eg moz-extension://8d66093c-c373-954f-91d5-1fcdde232a5a/popup/src/main/kotlin/popup.kt) some can't (moz-extension://8d66093c-c373-954f-91d5-1fcdde232a5a/src/main/kotlin/extensionTypes/extensionTypes.kt). When they fail to open, the logged error is:

Error while fetching an original source: TypeError: NetworkError when attempting to fetch resource.
Source URL: moz-extension://8d66093c-c373-954f-91d5-1fcdde232a5a/src/main/kotlin/extensionTypes/extensionTypes.kt

But looking at my sources locally I can't find any extensionTypes.kt file, so maybe the sourcemap is faulty?

Flags: needinfo?(jdescottes)

I just tested the extension recently and sourcemaps seem to work for me. I know this is a very old bug and sorry for not having a look earlier, but could you have a look and confirm? Thanks!

Flags: needinfo?(kirill.rakhman)

Happy to re-open if you see an issue.

Closed: 5 years ago
Resolution: --- → FIXED
You need to log in before you can comment on or make changes to this bug.