Invalid modules list when using hugo workspace

[deining]

What version of Hugo are you using (hugo version)?

hugo v0.123.3-a75a659f6fc0cb3a52b2b2ba666a81f79a459376+extended linux/amd64 BuildDate=2024-02-23T17:09:20Z VendorInfo=gohugoio

Does this issue reproduce with the latest release?

Yes

Reproduction:

git clone --single-branch -b hugo-workspace https://github.com/deining/hugo-test
cd hugo-test/exampleSite/
hugo mod vendor

Build of the site fails:

hugo
Total in 3 ms
Error: failed to load modules: invalid modules list: "/home/andreas/hugo-test/exampleSite/hugo-test/exampleSite/_vendor/modules.txt"

The only module listed inside the file m̀odules.txt generated from hugo mod vendor does not held version information, which causes hugo to exit prematurely.

Reference: https://discourse.gohugo.io/t/invalid-modules-list-when-using-hugo-workspace/48498