feat(gatsby): Add JSX Runtime options to gatsby-config.js

[herecydev]

Description

Follow up to #32972.

Allow automatic react runtime to be enabled through config, the current workaround is to start manually setting babelPlugins and eslint config. There's going to be very few people doing this for something that is supposed to work out the box

Related Issues

Fixes #28657
Fixes #30373

[herecydev]

Might need further elaboration?

[wardpeet]

Awesome! Thank you very much.

Could you also add:

• "react/jsx-uses-react": "off" to eslint-config.ts

[wardpeet]

Could we move to these 2 options please.

Suggested change

	jsxAutomaticRuntime: Joi.boolean().default(false),
	jsxRuntime: Joi.string().default('classic'),
	jsxImportSource: Joi.string()

[herecydev]

* "react/jsx-uses-react": "off"

Added that, it looks like the eslint rule won't scan node_modules so plugins will be able to "mix and match" without throwing eslint errors. In addition enforced that the jsxRuntime == "automatic" | "classic"

[herecydev]

Might have missed your last part of the comment

jsxImportSource: Joi.string()

What do you want this to do?

[wardpeet]

We should also set an option to change the importSource to for example to emotion. Ideally, we want to also add an action so plugins can set it themselves

importSource is similar to @jsx pragma

[herecydev]

@wardpeet I think this is good to go now, jsxRuntime works as expected, jsxImportSource is present but nothing listens to it at the moment (I think another PR could take care of that, preferably someone with emotion pragma experience).

There's a failing test but I'm convinced that's unrelated.

[herecydev]

@wardpeet I'm struggling with these tests, is it usual to have this level of flake (each run through spits out some new error). I also have no means to rerun this stuff and try and get it through!

[vladar]

@wardpeet This is a new feature, not a hotfix - do we actually want to backport it to v3? If so, this likely needs a minor release, not a patch.