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Ideally I think we should pass the sourcesContent all along the way and inject null sourcesContent in the end before passing to browsers. I believe that will fix many "missing source files" warning issues.

I don't know why excludeContent was true in the first place (103dec9#diff-071a32aedd2ea59472ebb69fb456e818b103d1a332da632e12c2d54395938ad1).

I seems we are not handling cases like sourcesContent: [null, 'content'] and sourcesContent: ['content'], sources: ['non-existent path']. The former will have null sourcesContent that should be transformed to 'content' by reading from the file, and the latter will output a warning that should not be output because the content already exists.

Would it be possible to replace the non-exist path with null in sources and just keep its 'content' in sourcesContent via injectSourcesContent?

If so, it would be a lot easier to judge whether it's fine to combineSourcemaps with excludeContent=true

Would it be possible to replace the non-exist path with null in sources and just keep its 'content' in sourcesContent via injectSourcesContent?

We should not replace non-existent path with null. The spec says sourcesContent field can contain null but not for sources field. Also browsers/debuggers can show the original path if sources included the non-exist path.

The former will have null sourcesContent that should be transformed to 'content' by reading from the file, and the latter will output a warning that should not be output because the content already exists.

Let me elaborate this sentence just in case. I mean

• { "sourcesContent": [null], "sources": ["existent-path"] } should be transformed to { "sourcesContent": ["content from file"], "sources": ["existent-path"] } (currently Vite does not replace null with the actual content)
• { "sourcesContent": ['content'], "sources": ["non-existent-path"] } should not output a warning (currently Vite outputs a warning)

at these lines.

Yeah, I understand what you mean, my question is if we don't replace non-exist-path with null then how to judge whether excludeContent or not in combineSourcemaps

excludeContent needs to be false unconditionally to pass sourcesContent all along the way.