Vite 5.4.0 env var fails when bundling Vite-bundled library

[bluwy]

Describe the bug

This was brought up at #17648 (comment)

When a library uses Vite (library mode) to bundle and uses env var, the const __vite_import_meta_env__ = { may get included in the code. When that happens and we bundle that library in our app, we re-inject the variable declaration again here, which causes a runtime error:

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

Lines 139 to 148 in fcf50c2

	// If there's bare `import.meta.env` references, prepend the banner
	if (bareImportMetaEnvRe.test(result.code)) {
	result.code = banner + result.code
	if (result.map) {
	const map = JSON.parse(result.map)
	map.mappings = ';' + map.mappings
	result.map = map
	}
	}

Reproduction

silverwind/vite-import-meta#1

Steps to reproduce

No response

System Info

n/a

Used Package Manager

npm

Logs

Click to expand

error during build:
[commonjs--resolver] node_modules/lib/dist/index.js (3392:6): Identifier "__vite_import_meta_env__" has already been declared
file: node_modules/lib/dist/index.js:3392:6

3390: const create = (createState) => createState ? createImpl(createState) : createImpl;
3391: const __vite_import_meta_env__ = { "BASE_URL": "/", "DEV": false, "MODE": "production", "PROD": true, "SSR": false };
3392: function createJSONStorage(getStorage, options2) {
            ^
3393:   let storage;
3394:   try {

    at getRollupError (node_modules/vite/node_modules/rollup/dist/es/shared/parseAst.js:392:41)
    at error (node_modules/vite/node_modules/rollup/dist/es/shared/parseAst.js:388:42)
    at Module.error (node_modules/vite/node_modules/rollup/dist/es/shared/node-entry.js:13944:16)
    at ModuleScope.addDeclaration (node_modules/vite/node_modules/rollup/dist/es/shared/node-entry.js:7362:21)
    at ModuleScope.addDeclaration (node_modules/vite/node_modules/rollup/dist/es/shared/node-entry.js:12075:22)
    at Identifier.declare (node_modules/vite/node_modules/rollup/dist/es/shared/node-entry.js:6960:39)
    at VariableDeclarator.declareDeclarator (node_modules/vite/node_modules/rollup/dist/es/shared/node-entry.js:10661:17)
    at VariableDeclaration.initialise (node_modules/vite/node_modules/rollup/dist/es/shared/node-entry.js:12343:24)
    at convertNode (node_modules/vite/node_modules/rollup/dist/es/shared/node-entry.js:13167:10)
    at convertNodeList (node_modules/vite/node_modules/rollup/dist/es/shared/node-entry.js:13177:34)

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Make sure this is a Vite issue and not a framework-specific issue. For example, if it's a Vue SFC related bug, it should likely be reported to vuejs/core instead.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion or join our Discord Chat Server.
• The provided reproduction is a minimal reproducible example of the bug.

[bluwy]

On top of the discussions at #17648, I think it may be easiest to increment the variable name if the existing one is already used. Performance might be affected a bit, but not every module would access env vars so it's probably fine.

Another solution might be to give a different variable name when building in library mode, but that would still cause problems if the Vite library bundles an internal Vite library too.

[yuzheng14]

I think that we could use a virtual module like vite:importAnalysisBuild to let rollup handle the name.

[bluwy]

I don't think we need to go that far to resolve this naming issue. Doing an includes check to see if the variable name is used, and if so, append a 1, 2, etc to the variable name should be enough.

[yuzheng14]

I've created #17876 to fix this.

[pedro-rodrigues-la]

Also encountered this issue.
In my case I have a react library (created by me using vite) being used by another project (also using react and vite), both the library and the project uses the "import.meta" statement, no variable is declared with the same name between both but the env variable (default one created by vite) seems to be the one causing the conflict:

error during build: project/dist/project.js (2345:6): Identifier "__vite_import_meta_env__" has already been declared