2066073 - Convert tabgroup.js and tabsplitview.js to modules that export their class

Status: RESOLVED FIXED

(Firefox :: Tabbed Browser, task, P3)

Description

[Dão Gottwald [:dao]]

browser/components/tabbrowser/content/tabgroup.js and tabsplitview.js wrap their class in a block in a file loaded through Services.scriptloader.loadSubScript, so nothing can import the class. TypeScript cannot see MozTabbrowserTabGroup or MozTabSplitViewWrapper at all, which is why bug 2065814 describes them with hand-written interfaces. Nothing checks an interface against the class it describes, so it can drift, or simply be wrong, with no signal.

Convert both to modules that export their class and register it the way toolkit/content/widgets/browser-custom-element.mjs is registered from toolkit/content/customElements.js:

customElements.setElementCreationCallback("tab-group", () =>
  ChromeUtils.importESModule(url, { global: "current" })
);

Each interface then becomes a one-line reference to the real class.

These two are the cheap pair among the four element scripts:

• They extend MozXULElement, which tools/@types/lib.gecko.augmentations.d.ts already declares. tab.js and tabs.js extend MozElements.MozTab and MozElements.TabsBase, defined in toolkit/content/widgets/tabbox.js and declared nowhere; an undeclared base makes every inherited DOM member vanish, so those two need their bases declared first and are out of scope here.
• Nothing outside their own file names either class.
• global: "current" puts the module in the window's global, so the bare gBrowser reads keep resolving unchanged. Ambient declarations for the window globals are only needed to check these files, which is a separate question and not part of this.

One interaction to handle: bug 2065813 declares pinned, splitview and group as never set on these two interfaces, which is what lets Tabbrowser.sys.mjs read them off a tab-or-group union. Pointing an alias at the real class drops those declarations, so the aliases have to become an intersection of the class with them or fifteen union reads come back.

Comment 1

[Dão Gottwald [:dao]]

Attachment: Bug 2066073 - Rename the tab group and split view element scripts to .mjs. r?#tabbrowser-reviewers-rotation!

A pure move, ahead of the commit that makes them modules, so the rename stays visible to blame. The subscript loader does not read the extension, and dropping "use strict" only anticipates eslint parsing the file as a module.

Comment 2

[Dão Gottwald [:dao]]

Attachment: Bug 2066073 - Turn the tab group and split view elements into modules. r?#tabbrowser-reviewers-rotation!

Dropping the block the subscript loader needed reindents both files, so git diff -w is the change and nothing in it is more than mechanical. global: "current" puts each module in the window's global, so the bare gBrowser and SessionStore references keep resolving.

Comment 3

[Dão Gottwald [:dao]]

Attachment: Bug 2066073 - Type the tab group and split view elements from their classes. r?#tabbrowser-reviewers-rotation!

Nothing checked the stand-in interfaces against the classes, so what only the interfaces said now has to be said in the classes.

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/04c45753bee1
https://hg.mozilla.org/integration/autoland/rev/ea1611c010dd
Rename the tab group and split view element scripts to .mjs. r=tabbrowser-reviewers,jswinarton
https://github.com/mozilla-firefox/firefox/commit/60ad9d1eb17a
https://hg.mozilla.org/integration/autoland/rev/dcb5eb5efca7
Turn the tab group and split view elements into modules. r=tabbrowser-reviewers,sthompson
https://github.com/mozilla-firefox/firefox/commit/c3d3e434db8e
https://hg.mozilla.org/integration/autoland/rev/ed39ec09aaed
Type the tab group and split view elements from their classes. r=tabbrowser-reviewers,sthompson

Comment 5

[Dão Gottwald [:dao]]

Attachment: Bug 2066073 - Ignore the tab group and split view reindent in blame and annotate. r?#firefox-desktop-core-reviewers

Comment 6

[Sandor Molnar[:smolnar]]

https://hg.mozilla.org/mozilla-central/rev/ea1611c010dd
https://hg.mozilla.org/mozilla-central/rev/dcb5eb5efca7
https://hg.mozilla.org/mozilla-central/rev/ed39ec09aaed

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/4290620514a8
https://hg.mozilla.org/integration/autoland/rev/2be2b67940f0
Ignore the tab group and split view reindent in blame and annotate. r=firefox-desktop-core-reviewers ,mossop