fix(yarn): Do not fail for workspaces with interdependent packages

When a Yarn workspace project contains packages with a dependency
inbetween, then it creates a symbolic link to the directories of the
packages in the `node_module` directory during `yarn install`.

In this case the directories returned by `findWorkspaceSubmodules()`
point to these symbolic links instead of to the real file / directory.
This results in `ModuleInfo.isProject` getting assigned to `false` for
`pkg2`, which in turn leads to a `yarn info pkg2` call. As `pkg2` is
not published, that call fails which in turn fails the entire analysis.

Fix that by returning the real submodule directories, so that
`isProject` is assigned correctly.

Note: The dependency added to the `package.json` has to specify the
      version [1] in order to not run into a yarn issue.

[1]: yarnpkg/yarn#4878 (comment)

Signed-off-by: Frank Viernau <[email protected]>

Author: fviernau

plugins/package-managers/node/src/funTest/assets/projects/synthetic/yarn/workspaces-expected-output.yml

@@ -75,6 +75,17 @@ projects:
           dependencies:
           - id: "NPM::tr46:0.0.3"
           - id: "NPM::webidl-conversions:3.0.1"
+    - id: "Yarn::pkg2:1.0.0"
+      linkage: "PROJECT_DYNAMIC"
+      dependencies:
+      - id: "NPM:@here:harp-fetch:0.3.6"
+        dependencies:
+        - id: "NPM::node-fetch:2.7.0"
+          dependencies:
+          - id: "NPM::whatwg-url:5.0.0"
+            dependencies:
+            - id: "NPM::tr46:0.0.3"
+            - id: "NPM::webidl-conversions:3.0.1"
 packages:
 - id: "NPM::node-fetch:2.7.0"
   purl: "pkg:npm/[email protected]"

plugins/package-managers/node/src/funTest/assets/projects/synthetic/yarn/workspaces/packages/pkg1/package.json

@@ -3,6 +3,7 @@
   "version": "1.0.0",
   "license": "Apache-2.0",
   "dependencies": {
-    "@here/harp-fetch": "^0.11.0"
+    "@here/harp-fetch": "^0.11.0",
+    "pkg2": "^1.0.0"
   }
 }

plugins/package-managers/node/src/main/kotlin/yarn/Yarn.kt

@@ -125,7 +125,7 @@ open class Yarn(override val descriptor: PluginDescriptor = YarnFactory.descript
             dir.walk().maxDepth(1).filter {
                 it.isDirectory && it.isSymbolicLink() && it != dir
             }
-        }
+        }.mapTo(mutableSetOf()) { it.realFile() }
     }
 
     override fun beforeResolution(