@swift-ci create

Since the error about the missing symbols comes from the compiler, it's a bit tricky to intercept the error message. One option would be to always generate the module accessor as a stub, and to mark it as unavailable so that you get a compile time error explaining that no resource bundle was generated used because there were no resources in the target (and then the target name, etc). I don't know the exact syntax but I know there is a way to mark a property as unavailable.

Comment by James Sherlock (JIRA)

Interesting idea there Anders about marking a property as unavailable, the syntax appears to be something like this:

@available(*, unavailable, message: "...")

This would be changes in the BuildPlan.swift (https://github.com/apple/swift-package-manager/blob/master/Sources/Build/BuildPlan.swift#L588-L596) – just need to work out where the check is for whether there are any resources available and route that through to the method. Once we have that simple availability boolean passed to the right function it's a trivial case of injecting the "available" declaration into the template.

Alternatively, I wonder if we are able to detect this earlier in the chain? I see within the PackageDescription4Loader.swift (https://github.com/apple/swift-package-manager/blob/master/Sources/PackageLoading/PackageDescription4Loader.swift#L149-L151) we actually trigger an error if you attempt to supply an empty array for resources. Do you think it's reasonable to further expand this logic to check for valid resources at the path given or is this the wrong time to be making this check?

What do you think?

Comment by James Sherlock (JIRA)

Initial experiment with part A of the above comment:

Sherlouk@3647a6a

Comment by James Sherlock (JIRA)

Merge Request: #2789

(This includes part B of the suggestion above)