Cds unable to find service implementation

[bartdeboer]

We have recently upgraded our application from cds 3 to cds 4.2.7. When running cds run in the project root folder everything runs perfectly. However when running cds run within the ./srv folder cds seems to be unable to find the service.js implementation. After some digging it looks like something goes wrong in @sap/cds/lib/srv/factory.js. Specifically the sibling function is resolving to the current path which results in an extra srv/ segment like srv/srv/.

const sibling = (d) => {
  const src = _source(d), home = path.resolve(src,'..')
  ...
}

It's unable to find the sibling Javascript implementation. This causes problems with our mta deployment setup (which will run cds run from within the srv/ folder).

Alternatively I tried setting the implementation through the impl annotation on the service.cds definition. But I can't seem to get it to work from both the root and srv/ path simultaneously.

Finally I tried to set the implementation through the kind annotation on the service.cds and specifying the implementation of that kind in .cdsrc.json. This caused an infinite loop:

@sap/cds/lib/srv/factory.js:

...
return _use (_required())

function _use (it) {
    ...
    if (typeof it === 'function') return _use (_required(), /*with:*/ o.impl = _function(it)) // NOSONAR
    ... 
}