1539195 - Add a Damp test for adding a breakpoint an original source of a massive bundle

Status: NEW

(DevTools :: Debugger, task, P3)

Description

[:Harald Kirschner :digitarald]

Follow up from Bug 1536201 where a massive regression wasn't caught and fixing it didn't change DAMP.

Test case should (just brainstorming) include:

• Babel/webpack generated
• Source maps
• Maybe Typescript
• Many files and npm dependencies

Given how important this case is it could maybe replace Complicated, Simple or Custom?

Comment 1

[Alexandre Poirot [:ochameau]]

It would either augment or duplicate custom. We should keep complicated which is a non-sourcemapped example.

Custom is being implemented over here:
https://searchfox.org/mozilla-central/source/testing/talos/talos/tests/devtools/addon/content/pages/custom/debugger
This was originally introduce to have a minimal coverage of a source mapped website.
We should probably replace it by a more complex source mapped web page and/or augment the test script to test new areas of the debugger:
https://searchfox.org/mozilla-central/source/testing/talos/talos/tests/devtools/addon/content/tests/debugger/custom.js#26-31

Comment 2

[Alexandre Poirot [:ochameau]]

Note that similar work should be done against bug 1521540 which did not trigerred any major difference on DAMP.

Comment 3

[:Harald Kirschner :digitarald]

David, do you have any thoughts on how we could address this?

Comment 4

[David Walsh :davidwalsh]

We should identify what we consider a modern sourcemapped app, create the necessary demo, and generate the damp test to:

1. Cover what cause the regression
2. Stress test what we believe could be slow

Comment 5

[Jason Laster [:jlast]]

The regression was fixed by https://phabricator.services.mozilla.com/D24365.

The root cause was the server was trying to call findScripts way too often when calculating breakpoint positions.

Comment 6

[:Harald Kirschner :digitarald]

Related, Logan mentioned that the WASM/source-map update did not really show up in DAMP as it has more impact in large-scale source-mapped environment: https://github.com/firefox-devtools/debugger/pull/7071 . Interesting to test if this change shows up in our new test.

Comment 7

[:Harald Kirschner :digitarald]

https://github.com/mozilla/hubs might be a good example, as it came up recently in bug 1607559.