Do not parse CSS on missed plugins or parser/stringifier option

Right now we are showing warning:

You did not set any plugins, parser, or stringifier. Right now, PostCSS does nothing. Pick plugins for your case on https://www.postcss.parts/ and use them in postcss.config.js.

https://github.com/postcss/postcss/blob/main/lib/processor.js#L19

But many people complain that they can fix it since PostCSS is used wrongly somewhere inside build pipeline.

We can avoid warning if PostCSS will not parse CSS in this case. We can add something like NoWorkResult, where NoWorkResult#css key will be equal to input. On NoWorkResult#root read we still need to parse CSS. And we need to find the best way to deal with NoWorkResult#map.

[ai]

If we want to create an actual source map we need still to parse AST because it adds mappings on nodes

If there are no changes between input and output, you can add only a single map mapping from the whole file to the whole file.

You do not need to create mapping per each CSS part if there are no changes.

[bogdan0083]

If we want to create an actual source map we need still to parse AST because it adds mappings on nodes

If there are no changes between input and output, you can add only a single map mapping from the whole file to the whole file.

You do not need to create mapping per each CSS part if there are no changes.

Got it, thanks.