1608567 - Multi-second hang for minified file

Status: NEW

(DevTools :: Debugger, defect, P3)

Description

[:Harald Kirschner :digitarald]

No good STR, sorry. I debugged codesandbox output and paused on event handler. This paused in LastPass' minified content script. Loading this script caused several minutes of hangs, even after I switched away from the tab.

30s of that are captured in https://perfht.ml/2QH5Mbp

setDebugLine is triggered a lot.

Comment 1

[:Harald Kirschner :digitarald]

Analysis draft:

DebugLine.js is a PureComponent and has 3 props: location , why and source.

So what changes so often … the prop frame:

Before

  {
    "id": "server0.conn0.child1/frame28",
    "displayName": "execute/<",
    "location": {
      "sourceId": "sourceURL-https://github.githubassets.com/assets/github-bootstrap-2763eb02.js/originalSource-a10863dd7db0e216177b98f701567864",
      "sourceUrl": "https://github.githubassets.com/app/assets/modules/github/characters-remaining.js",
      "line": 31,
      "column": 4
    }
  }

After:

  {
    "id": "server0.conn0.child1/frame28",
    "displayName": "execute/<",
    "location": {
      "sourceId": "sourceURL-https://github.githubassets.com/assets/github-bootstrap-2763eb02.js/originalSource-a10863dd7db0e216177b98f701567864",
      "sourceUrl": "https://github.githubassets.com/app/assets/modules/github/characters-remaining.js",
      "line": 31,
      "column": 4
    }
  }
]

Then again, frame isn't even used in the component itself.

frame was added in https://github.com/firefox-devtools/debugger/pull/7779 , not sure when it was removed from props while still being used in redux mapping.

Comment 2

[:Harald Kirschner :digitarald]

Attachment: Bug 1608567 - Remove frame prop from DebugLine r=jlast

Comment 3

[BugBot [:suhaib / :marco/ :calixte]]

There's a r+ patch which didn't land and no activity in this bug for 2 weeks.
:Harald, could you have a look please?
For more information, please visit auto_nag documentation.

Comment 4

[:Harald Kirschner :digitarald]

Hefty test failures across the board. This is not the easy prop change that I thought it is.