fix: Directory.getSourceFile should only return source files currentl…

…y existing within the cache.

It shouldn't return source files on the disk. That is done by addExistingSourceFile.

src/fileSystem/Directory.ts

@@ -152,7 +152,10 @@ export class Directory {
     getSourceFile(pathOrCondition: string | ((sourceFile: SourceFile) => boolean)) {
         if (typeof pathOrCondition === "string") {
             const path = FileUtils.getStandardizedAbsolutePath(this.global.fileSystem, pathOrCondition, this.getPath());
-            return this.global.compilerFactory.getSourceFileFromFilePath(path);
+            if (this.global.compilerFactory.containsSourceFileAtPath(path))
+                return this.global.compilerFactory.getSourceFileFromFilePath(path);
+            else
+                return undefined;
         }
 
         return ArrayUtils.find(this.getSourceFiles(), pathOrCondition);

src/tests/fileSystem/directoryTests.ts

@@ -453,11 +453,18 @@ describe(nameof(Directory), () => {
     describe(nameof<Directory>(d => d.getSourceFile), () => {
         const ast = getAst();
         const directory = ast.createDirectory("dir");
+        const existingFile = directory.createSourceFile("existing-file.ts");
+        existingFile.saveSync();
+        existingFile.forget();
         const child1 = directory.createSourceFile("child1.ts");
         const child2 = directory.createSourceFile("child2.ts");
         const subDir = directory.createDirectory("subDir");
         const child3 = subDir.createSourceFile("child3.ts");
 
+        it("should not return a file that doesn't exist internally", () => {
+            expect(directory.getSourceFile("existing-file.ts")).to.be.undefined;
+        });
+
         it("should get based on the name", () => {
             expect(directory.getSourceFile("child2.ts")!.getFilePath()).to.equal(child2.getFilePath());
         });