@shopify/cli@3.93.1 payment customization (typescript) issue

Shopify CLI and Libraries
1

I have reproduced the issue on the latest CLI version.

Yes, I am on the latest version

I have searched existing posts and this report is not a duplicate.

Yes, this isn’t a duplicate

In which of these areas are you experiencing a problem?

Extension

Expected behavior

Running yarn test on a freshly generated payment customization (TypeScript) extension should pass without any changes.
The WASM filename used by @shopify/shopify-function-test-helpers (wasmPath from getFunctionInfo) should match the actual build output from buildFunction (either both index.wasm or both function.wasm).

Actual behavior

Vitest fails on the default integration test:

yarn run v1.22.22
$ vitest

 DEV  v3.2.4 /Users/leo/w/ps/app-overland/extensions/payment-customization

 ❯ tests/default.test.js (1 test | 1 failed) 5018ms
   × Default Integration Test > runs no-operations.json 13ms
     → expected 'function-runner failed with exit code…' to be null

 FAIL  tests/default.test.js > Default Integration Test > runs no-operations.json
AssertionError: expected 'function-runner failed with exit code…' to be null

- Expected:
null

+ Received:
"function-runner failed with exit code 1: Error: Couldn't load the Function \"/Users/leo/w/app/extensions/payment-customization/dist/index.wasm\": failed to read from `/Users/leo/w/app/extensions/payment-customization/dist/index.wasm`
"

Reproduction steps

  1. Use Shopify CLI to create a new app and a payment customization extension in TypeScript
  2. Go to the extension directory
  3. Install dependencies
  4. Build the function
  5. Run the default tests

Verbose output

Vitest fails on the default integration test:

yarn run v1.22.22
$ vitest

 DEV  v3.2.4 /Users/leo/w/ps/app-overland/extensions/payment-customization

 ❯ tests/default.test.js (1 test | 1 failed) 5018ms
   × Default Integration Test > runs no-operations.json 13ms
     → expected 'function-runner failed with exit code…' to be null

 FAIL  tests/default.test.js > Default Integration Test > runs no-operations.json
AssertionError: expected 'function-runner failed with exit code…' to be null

- Expected:
null

+ Received:
"function-runner failed with exit code 1: Error: Couldn't load the Function \"/Users/leo/w/app/extensions/payment-customization/dist/index.wasm\": failed to read from `/Users/leo/w/app/extensions/payment-customization/dist/index.wasm`
"

Operating system

Mac OS

CLI version

3.93.1

Shell

iTerm2

Nodejs version

v22.17.0

What language and version are you using in your application?

python + typescript