Should 1 be supported? Isn't the user asking Vite to do two incompatible things? Shouldn't we enforce the user to have string values for import.meta.env.xxx?

{
  define: {  'import.meta.env.VITE_BOOL': JSON.stringify('true') }
}

Should 1 be supported? Isn't the user asking Vite to do two incompatible things? Shouldn't we enforce the user to have string values for import.meta.env.xxx?

{
  define: {  'import.meta.env.VITE_BOOL': JSON.stringify('true') }
}

Sorry I didn't describe this case clearly. First of all, vite didn't restrict users from defining the non-string import.meta.env.xxx values according to the UserConfig.define types and the playground/env test cases.

And when I set {define: { 'import.meta.env.VITE_BOOL': X}}, what I expected is that import.meta.env.VITE_BOOL will be replaced with X and import.meta.env will be replaced with {"VITE_BOOL": X} no matter what VITE_BOOL value is in .env files after building.

Some more context about this PR here. We discussed with @sun0day and @bluwy, that it is a good idea to move forward with this PR as it is clear that define always win against .env. But later on, it may be helpful to issue a warning if there is a non-string value in define that is also defined in .env.