Find main classes in projects whose sources are linked in

[Artem (sorteam)]

ResolveMainClassHandler.resolveMainClassUnderPaths builds the search scope by keeping only the
projects whose own location is inside the requested folder:

projects = Stream.of(ProjectUtils.getAllProjects())
    .filter(p -> ProjectUtils.isJavaProject(p) && p.getLocation() != null
                 && ResourceUtils.isContainedIn(p.getLocation(), parentPaths))

A project can instead keep its description outside that folder and reach the sources through linked
folders. Such a project is dropped before the search runs, so the folder looks as if it contained no
main class: Run and Debug generates no Java configuration for it (the launch configuration
provider calls vscode.java.resolveMainClass(folder.uri)), and anything else that resolves a main
class by folder gets an empty answer.

The code already knows about this shape. acceptSearchMatch makes an exception for the invisible
project:

if (parentPaths.isEmpty()
    || ResourceUtils.isContainedIn(project.getLocation(), parentPaths)
    || isContainedInInvisibleProject(project, parentPaths)) {

but the scope filter it depends on has no such exception, so the invisible-project branch can never
fire - the project is not in the scope to begin with.

Fix

Check the locations of the project's source folders as well, in both places: for each source entry of
the raw classpath, resolve the workspace path through IWorkspaceRoot.findMember and compare that
location against the requested folders. A project belongs to the folder its sources are in rather
than to the folder its description happens to live in.

Reproduction

Create a java project whose source folders are linked resources pointing into a workspace folder,
with the project's own location elsewhere (any importer that provisions projects outside the
repository does this; the invisible project is a one-link special case of it). Open the workspace
folder and note that Run and Debug offers no Java configuration, while the same sources in a
regular project do.

Verification

I compiled the modified class against the plugin jar shipped in vscjava.vscode-java-debug 0.59.0
and the jdt.ls plugins from redhat.java. I have not run the project's Maven build or test
suite.

[Artem (sorteam)]

@microsoft-github-policy-service agree