This action should fail if no documentation is compiled

[wilfwilson]

Currently (see e.g. gap-packages/sgpdec#21) this action can silently pass even if it's not actually compiling any documentation.

I'm not sure how to do this.

I guess we would want to look for the existence of the generated files. But they could have different names/be in different places for different files.

Perhaps we could count the number of HTML files found by find in the package, and then after attempting to compile the manual, checking whether that number has increased? A bit hacky.

Is there some generated documentation file that all packages have, in the same place? Ah! We could look at the PackageInfo.g file for the PackageDoc.{HTMLStart,PDFFile,SixFile} component!

[stertooy]

I'm not sure if this is an acceptable or sufficient solution, but one can add the "if-no-files-found: error" flag to the upload-artifact action (example).

[wilfwilson]

Thank you for the suggestion.

Yes, it is probably a sufficient solution, but it would unfortunately require changing the Workflow file of every package that uses this build-pkg-docs action, and the point of this action is to avoid having to make such changes to all packages 😉. But for now we could at least add this flag to the example package's workflow file.