I don't think this is technically a breaking change, but it's a very notable one so let's include it in v41 so there's a higher chance everyone notices.

Definitely needs some docs updating!

Where should it be added?

Probably a few places where we mention coding file types. Alone should recommend using jsonc instead of json5

Is there any chance of .jsonc being added as a valid file extension for Renovate configs here?:

@viceice I think it's strictly not a breaking change, but it's a significant one that I'd like to bundle in a major release note so increase the chance of getting more attention. I'd like to recommend jsonc instead of json5 too in future (because we can more easily write migration code)

Just repeating this in case it was missed:

Is there any chance of .jsonc being added as a valid file extension for Renovate configs here?:

renovate/lib/config/app-strings.ts

Lines 1 to 12 in cdbaa1f

	export const configFileNames = [
	'renovate.json',
	'renovate.json5',
	'.github/renovate.json',
	'.github/renovate.json5',
	'.gitlab/renovate.json',
	'.gitlab/renovate.json5',
	'.renovaterc',
	'.renovaterc.json',
	'.renovaterc.json5',
	'package.json',
	];

VS Code treats a .json file as strictly JSON, so it does not allow comments.

To get rid of those errors, I can rename the file to renovate.jsonc, but then (unless I've misunderstood something) Renovate won't automatically find it.

@reduckted it's not necessary to add in v41.0.0 as it would be a new capability instead of something changed about existing functionality

@reduckted it's not necessary to add in v41.0.0 as it would be a new capability instead of something changed about existing functionality

I don't understand what you mean. What a the point of supporting .jsonc files if Renovate won't automatically find them?

This not about supporting .jsonc files. It's about using JSONC parsing instead of JSON parsing for JSON files

I don't understand what you mean. What a the point of supporting .jsonc files if Renovate won't automatically find them?

This not about supporting .jsonc files. It's about using JSONC parsing instead of JSON parsing for JSON files

Interesting, why would Renovate support the JSONC syntax without supporting the .jsonc file extension?

Seems like that's probably confusing and has bad DX, eg. editors showing errors in the file, other tooling which expects strict JSON in .json files, etc.

I can understand it for "any config files without file extension (e.g. .renovaterc)" mentioned in #29535, but supporting it for .json files seems anti-interop.

Seems like that's probably confusing and has bad DX

Totally agree. I know the issue says "Renovate should support JSONC for .json files", but if I didn't know this and I see that Renovate supports JSONC syntax and then I get error highlighting in my .json file, then I'm very likely going to change the file extension to .jsonc.

I assume that at some point in the future you're going to support .jsonc files, but why not do it as part of this change? It's only four lines that need to be added to that array and it's done, right?

We do not want to change more than is necessary in this PR. You're welcome to submit a PR after v41 which adds .jsonc support.