JS: Add test and support for providesModule

Author: asgerf

javascript/ql/lib/semmle/javascript/internal/paths/PathExprResolver.qll

@@ -175,6 +175,15 @@ module ResolveExpr<exprSig/1 shouldResolveExpr> {
     )
   }
 
+  pragma[nomagic]
+  private Container getJSDocProvidedModule(string moduleName) {
+    exists(JSDocTag tag |
+      tag.getTitle() = "providesModule" and
+      tag.getDescription().trim() = moduleName and
+      tag.getFile() = result
+    )
+  }
+
   /**
    * Holds if `expr` should be resolved as `path` relative to `base`.
    */
@@ -200,6 +209,9 @@ module ResolveExpr<exprSig/1 shouldResolveExpr> {
       path = expr.getValue().suffix(packageName.length()).regexpReplaceAll("^[/\\\\]", "") and
       base = pkg.getFolder()
     )
+    or
+    base = getJSDocProvidedModule(expr.getValue()) and
+    path = ""
   }
 
   private module ResolverConfig implements Folder::ResolveSig {

javascript/ql/test/library-tests/PathResolution/JSDocProvide/lib.js

@@ -0,0 +1,5 @@
+/**
+ * @providesModule jsdoc-provided-module/foo/bar/baz
+ */
+
+export const x = 1;

javascript/ql/test/library-tests/PathResolution/JSDocProvide/main.js

@@ -0,0 +1 @@
+import 'jsdoc-provided-module/foo/bar/baz'; // $ importTarget=JSDocProvide/lib.js

javascript/ql/test/library-tests/PathResolution/test.expected

@@ -67,6 +67,7 @@
 | Extended/src/main.ts:24:1:24:17 | import "@/index"; | Extended/lib/index.ts |
 | Extended/src/main.ts:25:1:25:20 | import "@/index.ts"; | Extended/lib/index.ts |
 | Extended/src/main.ts:26:1:26:20 | import "@/index.js"; | Extended/lib/index.ts |
+| JSDocProvide/main.js:1:1:1:43 | import  ... r/baz'; | JSDocProvide/lib.js |
 | NoBaseUrl/src/main.ts:2:1:2:21 | import  ... /file"; | NoBaseUrl/lib/file.ts |
 | NoBaseUrl/src/main.ts:3:1:3:24 | import  ... le.ts"; | NoBaseUrl/lib/file.ts |
 | NoBaseUrl/src/main.ts:4:1:4:24 | import  ... le.js"; | NoBaseUrl/lib/file.ts |