1808300 - Can't open a Multiprocess Toolbox from about:debugging when connected to an older server

Status: RESOLVED FIXED

(DevTools :: Framework, defect, P3)

Description

[Nicolas Chevobbe [:nchevobbe]]

Steps to reproduce

1. Start an older server (e.g. /Applications/Firefox.app/Contents/MacOS/firefox --start-debugger-server 6081)
2. On Nightly, go to about:debugging and connect to the older server
3. On the "Process" section, there should be "Multiprocess Toolbox" and an "inspect" button, click on it

Expected results

A toolbox opens in a new tab

Actual results

A tab is added but it is blank.
The following error is thrown:

console.error: "Exception while opening the toolbox" "Error: Unsupported target type 'frame'" (new Error("Unsupported target type 'frame'", "resource://devtools/shared/commands/target/target-command.js", 500))
startListening@resource://devtools/shared/commands/target/target-command.js:500:15

this comes from https://searchfox.org/mozilla-central/rev/abf6758ed833c203f84703aa2e3e3d317571b1e9/devtools/shared/commands/target/target-command.js#459,479-481,499-501

async startListening({ isTargetSwitching = false } = {}) {
...
    // Only a few top level targets support the watcher actor at the moment (see WatcherActor
    // traits in the _form method). Bug 1675763 tracks watcher actor support for all targets.
    if (this.hasTargetWatcherSupport(type)) {
...
    } else {
      throw new Error(`Unsupported target type '${type}'`);
    }

Comment 1

[Julian Descottes [:jdescottes]]

Probably a recent regression. Works fine from DevEdition and worked fine before updating my Nightly.

Comment 2

[Julian Descottes [:jdescottes]]

Ah it seems to only happen when switching to multiprocess, devtools.browsertoolbox.scope = "everything"

Comment 3

[Julian Descottes [:jdescottes]]

Attachment: Bug 1808300 - [devtools] Fix backward compatibility issue when using multiprocess browser toolbox from about:debugging

Older servers still need the boolean isBrowserToolboxFission for getWatcher/getTarget.

Comment 4

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

Set release status flags based on info from the regressing bug 1625939

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/0f68b296f796
[devtools] Fix backward compatibility issue when using multiprocess browser toolbox from about:debugging r=devtools-reviewers,ochameau

Comment 6

[Marian-Vasile Laza]

https://hg.mozilla.org/mozilla-central/rev/0f68b296f796