[2.x] hmr bug: can't implement hmr for custom file type such as .mdx

[csr632]

Describe the bug

I can't make hmr works with custom file type such as .mdx. It alway do full reload.

Reproduction

https://github.com/csr632/test-vite/tree/hmr-bug

vite serve and edit Doc.mdx. It alway do full reload.

After some debugging, I found out that the module graph is incorrect:
For a single .mdx module, vite creates two duplicate ModuleNode:

The ?import query cause duplicate ModuleNode. The query is added here:

vite/packages/vite/src/node/plugins/importsAnalysis.ts

Line 260 in b782af4

url = markExplicitImport(url)

This line doesn't add ?import query to .vue file, that's why @vitejs/plugin-vue doesn't suffer from this bug.

The source code of vite-plugin-mdx is here

How to fix

I suggest we remove the vue in this line:

vite/packages/vite/src/node/utils.ts

Line 74 in 206b7b7

const knownJsSrcRE = /\.((j|t)sx?|mjs|vue)($|\?)/

This is the only place where vite is still coupling with vue, giving "privilege" to vue.

After we change this line, @vitejs/plugin-vue should also be suffering from this bug.

Then, if the bug is fixed for @vitejs/plugin-vue, we can be sure that no other file types will suffer from this bug.

@yyx990803 Could you change this line and fix the bug for @vitejs/plugin-vue?

System Info

• required vite version: 2.0.0-beta.3
• required Operating System: Ubuntu
• required Node version: 12.13.0

[yyx990803]

https://vitejs.dev/config/#transforminclude

For reference: https://github.com/vuejs/vitepress/blob/master/src/node/plugin.ts

[csr632]

https://vitejs.dev/config/#transforminclude

For reference: https://github.com/vuejs/vitepress/blob/master/src/node/plugin.ts

The transforminclude doesn't help. I have updated the reproduction: https://github.com/csr632/test-vite/tree/hmr-bug

Actually I don't think transforminclude is needed in this case because I explicitly import Doc from "./Doc.mdx". The ?import query already do the job of transforminclude.