Include type reference directives in symlink cache, wait until program is present to create it (#44259)

* Fix discovery of more pnpm symlinks

* Add some tests

* Never show pnpm paths in auto imports, even if there’s no other path

* Import statement completions can return none

* Fix tests

* Add failing test showing poor symlink cache reuse

* Fix test, fails for right reasons now

* Preserve cache built up during program creation, then fill in with program resolutions

* Remove obsolete comment

* Remove obsolete type assertion

* Revert fully filtering out ignored paths

src/testRunner/tsconfig.json

@@ -213,6 +213,7 @@
         "unittests/tsserver/session.ts",
         "unittests/tsserver/skipLibCheck.ts",
         "unittests/tsserver/smartSelection.ts",
+        "unittests/tsserver/symlinkCache.ts",
         "unittests/tsserver/symLinks.ts",
         "unittests/tsserver/syntacticServer.ts",
         "unittests/tsserver/syntaxOperations.ts",

src/testRunner/unittests/tsserver/symlinkCache.ts

@@ -0,0 +1,80 @@
+namespace ts.projectSystem {
+    const appTsconfigJson: File = {
+        path: "/packages/app/tsconfig.json",
+        content: `
+        {
+            "compilerOptions": {
+                "module": "commonjs",
+                "outDir": "dist",
+                "rootDir": "src",
+                "baseUrl": "."
+            }
+            "references": [{ "path": "../dep" }]
+        }`
+    };
+
+    const appSrcIndexTs: File = {
+        path: "/packages/app/src/index.ts",
+        content: `import "dep/does/not/exist";`
+    };
+
+    const depPackageJson: File = {
+        path: "/packages/dep/package.json",
+        content: `{ "name": "dep", "main": "dist/index.js", "types": "dist/index.d.ts" }`
+    };
+
+    const depTsconfigJson: File = {
+        path: "/packages/dep/tsconfig.json",
+        content: `
+        {
+            "compilerOptions": { "outDir": "dist", "rootDir": "src", "module": "commonjs" }
+        }`
+    };
+
+    const depSrcIndexTs: File = {
+        path: "/packages/dep/src/index.ts",
+        content: `
+        import "./sub/folder";`
+    };
+
+    const depSrcSubFolderIndexTs: File = {
+        path: "/packages/dep/src/sub/folder/index.ts",
+        content: `export const dep = 0;`
+    };
+
+    const link: SymLink = {
+        path: "/packages/app/node_modules/dep",
+        symLink: "../../dep",
+    };
+
+    describe("unittests:: tsserver:: symlinkCache", () => {
+        it("contains symlinks discovered by project references resolution after program creation", () => {
+            const { session, projectService } = setup();
+            openFilesForSession([appSrcIndexTs], session);
+            const project = projectService.configuredProjects.get(appTsconfigJson.path)!;
+            assert.deepEqual(
+                project.getSymlinkCache()?.getSymlinkedDirectories()?.get(link.path + "/" as Path),
+                { real: "/packages/dep/", realPath: "/packages/dep/" as Path }
+            );
+        });
+    });
+
+    function setup() {
+        const host = createServerHost([
+            appTsconfigJson,
+            appSrcIndexTs,
+            depPackageJson,
+            depTsconfigJson,
+            depSrcIndexTs,
+            depSrcSubFolderIndexTs,
+            link,
+        ]);
+        const session = createSession(host);
+        const projectService = session.getProjectService();
+        return {
+            host,
+            projectService,
+            session,
+        };
+    }
+}