fix(compiler): No longer writes 0 length files outside of genDir (#10023)

Fixes: #9984

modules/@angular/compiler-cli/src/reflector_host.ts

@@ -18,9 +18,10 @@ const EXT = /(\.ts|\.d\.ts|\.js|\.jsx|\.tsx)$/;
 const DTS = /\.d\.ts$/;
 
 export interface ReflectorHostContext {
-  exists(fileName: string): boolean;
-  read(fileName: string): string;
-  write(fileName: string, data: string): void;
+  fileExists(fileName: string): boolean;
+  directoryExists(directoryName: string): boolean;
+  readFile(fileName: string): string;
+  assumeFileExists(fileName: string): void;
 }
 
 export class ReflectorHost implements StaticReflectorHost, ImportGenerator {
@@ -44,7 +45,7 @@ export class ReflectorHost implements StaticReflectorHost, ImportGenerator {
   }
   private resolve(m: string, containingFile: string) {
     const resolved =
-        ts.resolveModuleName(m, containingFile, this.options, this.compilerHost).resolvedModule;
+        ts.resolveModuleName(m, containingFile, this.options, this.context).resolvedModule;
     return resolved ? resolved.resolvedFileName : null;
   };
 
@@ -77,8 +78,7 @@ export class ReflectorHost implements StaticReflectorHost, ImportGenerator {
       if (this.options.trace) {
         console.log(`Generating empty file ${importedFile} to allow resolution of import`);
       }
-      this.compilerHost.writeFile(importedFile, '', false);
-      this.context.write(importedFile, '');
+      this.context.assumeFileExists(importedFile);
     }
 
     const importModuleName = importedFile.replace(EXT, '');
@@ -178,7 +178,7 @@ export class ReflectorHost implements StaticReflectorHost, ImportGenerator {
   }
 
   getMetadataFor(filePath: string): ModuleMetadata {
-    if (!this.context.exists(filePath)) {
+    if (!this.context.fileExists(filePath)) {
       // If the file doesn't exists then we cannot return metadata for the file.
       // This will occur if the user refernced a declared module for which no file
       // exists for the module (i.e. jQuery or angularjs).
@@ -186,7 +186,7 @@ export class ReflectorHost implements StaticReflectorHost, ImportGenerator {
     }
     if (DTS.test(filePath)) {
       const metadataPath = filePath.replace(DTS, '.metadata.json');
-      if (this.context.exists(metadataPath)) {
+      if (this.context.fileExists(metadataPath)) {
         return this.readMetadata(metadataPath);
       }
     } else {
@@ -200,7 +200,7 @@ export class ReflectorHost implements StaticReflectorHost, ImportGenerator {
 
   readMetadata(filePath: string) {
     try {
-      const result = JSON.parse(this.context.read(filePath));
+      const result = JSON.parse(this.context.readFile(filePath));
       return result;
     } catch (e) {
       console.error(`Failed to read JSON file ${filePath}`);
@@ -210,9 +210,21 @@ export class ReflectorHost implements StaticReflectorHost, ImportGenerator {
 }
 
 export class NodeReflectorHostContext implements ReflectorHostContext {
-  exists(fileName: string): boolean { return fs.existsSync(fileName); }
+  private assumedExists: {[fileName: string]: boolean} = {};
 
-  read(fileName: string): string { return fs.readFileSync(fileName, 'utf8'); }
+  fileExists(fileName: string): boolean {
+    return this.assumedExists[fileName] || fs.existsSync(fileName);
+  }
 
-  write(fileName: string, data: string): void { fs.writeFileSync(fileName, data, 'utf8'); }
+  directoryExists(directoryName: string): boolean {
+    try {
+      return fs.statSync(directoryName).isDirectory();
+    } catch (e) {
+      return false;
+    }
+  }
+
+  readFile(fileName: string): string { return fs.readFileSync(fileName, 'utf8'); }
+
+  assumeFileExists(fileName: string): void { this.assumedExists[fileName] = true; }
 }

modules/@angular/compiler-cli/test/mocks.ts

@@ -17,9 +17,11 @@ export interface Directory { [name: string]: Entry; }
 export class MockContext implements ReflectorHostContext {
   constructor(public currentDirectory: string, private files: Entry) {}
 
-  exists(fileName: string): boolean { return this.getEntry(fileName) !== undefined; }
+  fileExists(fileName: string): boolean { return typeof this.getEntry(fileName) === 'string'; }
 
-  read(fileName: string): string|undefined {
+  directoryExists(path: string): boolean { return typeof this.getEntry(path) === 'object' }
+
+  readFile(fileName: string): string|undefined {
     let data = this.getEntry(fileName);
     if (typeof data === 'string') {
       return data;
@@ -27,7 +29,7 @@ export class MockContext implements ReflectorHostContext {
     return undefined;
   }
 
-  write(fileName: string, data: string): void {
+  writeFile(fileName: string, data: string): void {
     let parts = fileName.split('/');
     let name = parts.pop();
     let entry = this.getEntry(parts);
@@ -36,6 +38,8 @@ export class MockContext implements ReflectorHostContext {
     }
   }
 
+  assumeFileExists(fileName: string): void { this.writeFile(fileName, ''); }
+
   getEntry(fileName: string|string[]): Entry|undefined {
     let parts = typeof fileName === 'string' ? fileName.split('/') : fileName;
     if (parts[0]) {
@@ -79,16 +83,18 @@ function normalize(parts: string[]): string[] {
 export class MockCompilerHost implements ts.CompilerHost {
   constructor(private context: MockContext) {}
 
-  fileExists(fileName: string): boolean { return this.context.exists(fileName); }
+  fileExists(fileName: string): boolean { return this.context.fileExists(fileName); }
 
-  readFile(fileName: string): string { return this.context.read(fileName); }
+  readFile(fileName: string): string { return this.context.readFile(fileName); }
 
-  directoryExists(directoryName: string): boolean { return this.context.exists(directoryName); }
+  directoryExists(directoryName: string): boolean {
+    return this.context.directoryExists(directoryName);
+  }
 
   getSourceFile(
       fileName: string, languageVersion: ts.ScriptTarget,
       onError?: (message: string) => void): ts.SourceFile {
-    let sourceText = this.context.read(fileName);
+    let sourceText = this.context.readFile(fileName);
     if (sourceText) {
       return ts.createSourceFile(fileName, sourceText, languageVersion);
     } else {
@@ -100,7 +106,7 @@ export class MockCompilerHost implements ts.CompilerHost {
     return ts.getDefaultLibFileName(options);
   }
 
-  writeFile: ts.WriteFileCallback = (fileName, text) => { this.context.write(fileName, text); }
+  writeFile: ts.WriteFileCallback = (fileName, text) => { this.context.writeFile(fileName, text); }
 
   getCurrentDirectory(): string {
     return this.context.currentDirectory;