1773603 - Cover *.js and *.jsm.js in the shim for ESM-ified module

Status: RESOLVED FIXED

(Core :: XPConnect, task, P1)

Description

[Tooru Fujisawa [:arai]]

As pointed out in bug 1609269 comment #8, non-*.jsm files are also referred from out-of-tree.
That means:

• we should keep the *.js extension
• we should cover *.js case with the shim
• we should directly migrate from *.js to .sys.mjs

Comment 1

[Tooru Fujisawa [:arai]]

Attachment: Bug 1773603 - Support resource URI with *.js and *.jsm.js extension in ESM shim. r?jonco!

Comment 2

[Tooru Fujisawa [:arai]]

also we need to cover .jsm.js

Comment 3

[Tooru Fujisawa [:arai]]

This patch adds the support for the following 2 cases, in addition to *.jsm to *.sys.mjs:

• JSM file with *.js extension is converted to ESM with *.sys.mjs
  • e.g. services/sync/modules/main.js to services/sync/modules/main.sys.mjs
• JSM file with *.jsm.js extension is converted to ESM with *.sys.mjs
  • e.g. devtools/client/performance-new/popup/background.jsm.js to devtools/client/performance-new/popup/background.sys.mjs

So, consumers that imports those modules with the current URL keeps working even if those files are renamed.
This should cover in-tree consumers (to make the migration easier, by making it smaller chunk), and out-of-tree consumers (extensions, etc).

Is there any other cases that I missed here, e.g. in devtools, newtab, remote, sync? also, is there any issue with the above?

Comment 4

[Alexandre Poirot [:ochameau]]

AFAIK, there is no official addon/code running in firefox that is hosted out of the tree for DevTools.
We have the "adp helper addon", but it doesn't run any JS and only distributes executables.

I think that the profiler no longer involves an addon and the profiler icon is now always managed by some in-tree code?

Otherwise, DevTools isn't using any special extension names and sticks to .jsm (for jsm) or .js (for common js modules).
Except in performance-new folder, where there is this .jsm.js trick for typescript.

Comment 5

[Julian Descottes [:jdescottes]]

Nothing to add on top of what Alex said for DevTools.
For remote/ I also don't think we have any out-of-tree consumer for any of our JSMs. Pinging :whimboo in case I am missing something.

Comment 6

[Julien Wajsberg [:julienw]]

Yeah, we don't use any addon in the profiler / performance-new code now. The files *.jsm.js are jsm, the js suffix is to trick typescript to look at these files, as we can't otherwise instruct typescript to look at specific suffixes.

Comment 7

[Henrik Skupin [:whimboo][⌚️UTC+1]]

I'm not aware that there is any code outside of our tree that actually uses our JSM files under /remote.

Comment 8

[Tooru Fujisawa [:arai]]

I was wrong, there wasn't non-*.jsm file in newtab component.

Comment 9

[Mark Hammond [:markh] [:mhammond]]

That plan sounds great to me for the services/* modules, thanks.

Comment 10

[Tooru Fujisawa [:arai]]

Thank you all!
looks like this will cover most of the cases and we can go with it.

If there's any other issue (such as, .sys.mjs cannot be used for some reason), we can still keep the compatibility by making a thin wrapper with existing jsm filename, that exposes new ESM file's symbols.

Comment 11

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/fe7b745e73f1
Support resource URI with *.js and *.jsm.js extension in ESM shim. r=jonco

Comment 12

[bszekely]

https://hg.mozilla.org/mozilla-central/rev/fe7b745e73f1