v6.3.3 ReferenceError: Cannot access '__vite_ssr_export_default__' before initialization

[cope]

Describe the bug

After upgrading from v6.3.2 to v6.3.3 my rather simple tests are failing with:

ReferenceError: Cannot access '__vite_ssr_export_default__' before initialization

Reverting back to v6.3.2 fixes it.

It looks like this message was introduced in 80a91ff:

I'm guessing, of course, but...

Reproduction

n/a

Steps to reproduce

the error is thrown on this highlighted line:

System Info

Windows and Linux and Docker...

Used Package Manager

pnpm

Logs

No response

Validations

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• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
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• The provided reproduction is a minimal reproducible example of the bug.

[github-actions]

Hello @cope. Please provide a minimal reproduction using a GitHub repository or StackBlitz. Issues marked with needs reproduction will be closed if they have no activity within 3 days.

[charlesmass2]

I just created a simple reproduction here : https://github.com/charlesmass2/Repro-vite-19929
Hope this is relevant.

[hi-ogawa]

@charlesmass2 Thanks for providing an example. However, this is an expected behavior and it's considered as a fix.

In your example, there is a cyclic import between Fancy.vue and useFancy.js. And this only works when useFancy.js is imported first. This can be verified by importing Fancy.vue on browser, which causes a similar error (this is not only Vite 6.3.3 but likely all pas versions of Vite) https://stackblitz.com/edit/github-a2a5ajtk?file=src%2FApp.vue

useFancy.js:3 Uncaught (in promise) ReferenceError: Cannot access 'Fancy' before initialization
    at useFancy.js:3:26

In addition to change of __vite_ssr_export_default__, we also fixed the execution order of export * #19841 and that's what affected your entry.js, which has:

export * from './Fancy.vue';
import './useFancy.js';

Previously, we executed useFancy.js before Fancy.vue, which was helping hiding the error, but Vite 6.3.3 fixed it to execute Fancy.vue before useFancy.js. In your case, you can flip export * and import to make your test pass again on Vite 6.3.3. https://stackblitz.com/edit/github-a2a5ajtk?file=src%2Fentry.js

[fabianszabo]

I really can't see how this error is a bugfix. 2 of my test files are crashing and one of the errors literally points at the same spot even if I comment out that line:

FAIL  src/views/tests/----.test.ts [ src/views/tests/----.test.ts ]
ReferenceError: Cannot access '__vite_ssr_export_default__' before initialization
 ❯ Module.get [as default] src/views/----.vue:1:103
      2| // Imports
      3| import { computed, onMounted, onUnmounted, ref } from "vue";
      4| // import { storeToRefs } from "pinia";
       |      ^

There will be a lot more people facing this issue once people start updating their dependencies.

[kfvv]

I've got the same error as described above:

ReferenceError: Cannot access '__vite_ssr_export_default__' before initialization
 ❯ Module.get [as default] .../Select.vue:1:103
      2| import { ref } from 'vue'
      3| import { useI18n } from 'vue-i18n'
      4| import { useRouter } from 'vue-router'

I tried changing the imports, awaiting for them, but no result:

const { ref } = await import('vue')
const { useI18n } = await import('vue-i18n')
const { useRouter } = await import('vue-router')

Downgrading to v6.3.2 seems like the only solution for now

[hi-ogawa]

Please provide a reproduction so we can understand the issue 🙏

[JammingBen]

The error messages can be a bit deceiving. The error doesn't come from importing some third party dependencies, but from importing your modules. Also, in the project I'm working in, it was not that obvious like in the reproduction repository above because the circular dependency ran through multiple files (e.g. file A imports file B, file B imports file C and file C imports some other file that imports file A).

The only thing that got me wondering is why it only happens with the tests but not during the runtime of the app.

[hi-ogawa]

The only thing that got me wondering is why it only happens with the tests but not during the runtime of the app.

As mentioned in #19929 (comment), this is partly because which entry is imported first matters when evaluating cyclic imports. For Vitest scenario, users tend to have arbitrary files to be imported for unit test, which can be different from the way it's imported in app usage. In fact, Vite itself has a broken cyclic import internally and thus we chose to a workaround as explained in #18983 (comment).

[fabianszabo]

Even so, the tests don't fail consistently based on cyclic imports.

Let me elaborate:
Only 2 of my test files are failing (note that the test is failing before it even runs the first unit test). However, I found that basically all of my composables and stores should fail due to cyclic imports. That's because I wrapped my axios instance in a composable and import my "Auth Store" which through a service imports my axios composable ("A imports B, B imports C, C imports A") I would expect all files that eventually import the axios composable to fail, but they don't.

 Test Files  2 failed | 55 passed (57)
      Tests  438 passed (438)
   Start at  11:33:04
   Duration  5.07s (transform 1.19s, setup 0ms, collect 12.96s, tests 1.70s, environment 15.68s, prepare 3.62s)

I was able to get rid of the "vite_ssr_export_default" message after removing the import of my "Auth Store" in my axios composable.

However I was also able to delete the two affected files and leave the cyclic import and get the tests to pass

 Test Files  55 passed (55)
      Tests  438 passed (438)
   Start at  11:53:44
   Duration  6.22s (transform 814ms, setup 0ms, collect 8.08s, tests 1.54s, environment 12.57s, prepare 2.46s)

I have compared the two files to other files to see if there is anything unique about them, but there is not. I removed all but one import (of a pinia store) in one of these 2 files and got the same error still. However, I import that exact pinia store and call the same functions in another file that passes the tests just fine.