1434081 - webpack-generated source maps have incorrect line numbers when page is force-reloaded

Status: RESOLVED FIXED

(DevTools :: Debugger, defect, P2)

Description

[William Lachance (:wlach)]

Here's a strange bug I've found with using source maps with a webpack application:

git clone https://github.com/wlach/react-metrics-graphics.git
cd react-metrics-graphics
git checkout source-map-failure
yarn install
yarn start

Go to http://localhost:5000
Force-reload page

Expected:

Should see a console.log statement saying "HEYA" referencing line 158

Actual:

see a console.log statement saying "HEYA" referencing line 77

If I load the page in a new tab with the web console open, most often it references the correct line number (force-reloading usually results in it having the wrong one again though). This feels like some kind of race condition. If I go into the debugger, it seems like it's referencing the webpack-internal version of the source map for the incorrect case.

Comment 1

[William Lachance (:wlach)]

I should add that this "just works" with Chrome.

Comment 2

[William Lachance (:wlach)]

This seems similar to bug 1400856, but I tried the proposed fix there (https://bugzilla.mozilla.org/show_bug.cgi?id=1400856#c3) and it did not help.

Comment 3

[William Lachance (:wlach)]

It seems like in the case that this works, the debugger is pointing to something called "webpack:///", whereas if it isn't, it's pointing to something called "webpack-internal:///".

Comment 4

[Tom Tromey :tromey]

(In reply to William Lachance (:wlach) (use needinfo!) from comment #2)
> This seems similar to bug 1400856, but I tried the proposed fix there
> (https://bugzilla.mozilla.org/show_bug.cgi?id=1400856#c3) and it did not
> help.

That would be my first guess, too.
Source maps in <script> elements don't really work correctly.  There are a
few bugs about this.
I don't think that patch in bug 1400856 is correct - I will comment there.

Comment 5

[Jason Laster [:jlast]]

I'

Comment 6

[Jason Laster [:jlast]]

I'd like to fix inline script source maps in the next couple of months.

Comment 7

[Jason Laster [:jlast]]

Hi William, i believe we've made improvements to inline source maps. Could you try re-testing this?

Comment 8

[William Lachance (:wlach)]

(In reply to Jason Laster [:jlast] from comment #7)

Hi William, i believe we've made improvements to inline source maps. Could you try re-testing this?

Yeah I've noticed this seems to be working well in general these days, happy to mark this as fixed.

Comment 9

[Jason Laster [:jlast]]

Great!