Draft of configuration inheritance

Jakefile.js

@@ -155,6 +155,7 @@ var harnessSources = harnessCoreSources.concat([
     "moduleResolution.ts",
     "tsconfigParsing.ts",
     "commandLineParsing.ts",
+    "configurationExtension.ts",
     "convertCompilerOptionsFromJson.ts",
     "convertTypingOptionsFromJson.ts",
     "tsserverProjectSystem.ts",

src/compiler/commandLineParser.ts

@@ -700,12 +700,54 @@ namespace ts {
       * @param basePath A root directory to resolve relative path entries in the config
       *    file to. e.g. outDir
       */
-    export function parseJsonConfigFileContent(json: any, host: ParseConfigHost, basePath: string, existingOptions: CompilerOptions = {}, configFileName?: string): ParsedCommandLine {
+    export function parseJsonConfigFileContent(json: any, host: ParseConfigHost, basePath: string, existingOptions: CompilerOptions = {}, configFileName?: string, resolutionStack: Path[] = []): ParsedCommandLine {
         const errors: Diagnostic[] = [];
-        const compilerOptions: CompilerOptions = convertCompilerOptionsFromJsonWorker(json["compilerOptions"], basePath, errors, configFileName);
-        const options = extend(existingOptions, compilerOptions);
+        const getCanonicalFileName = createGetCanonicalFileName(host.useCaseSensitiveFileNames);
+        const resolvedPath = toPath(configFileName || "", basePath, getCanonicalFileName);
+        if (resolutionStack.indexOf(resolvedPath) >= 0) {
+            return {
+                options: {},
+                fileNames: [],
+                typingOptions: {},
+                raw: json,
+                errors: [createCompilerDiagnostic(Diagnostics.Circularity_detected_while_resolving_configuration_Colon_0, [...resolutionStack, resolvedPath].join(" -> "))],
+                wildcardDirectories: {}
+            };
+        }
+
+        let options: CompilerOptions = convertCompilerOptionsFromJsonWorker(json["compilerOptions"], basePath, errors, configFileName);
         const typingOptions: TypingOptions = convertTypingOptionsFromJsonWorker(json["typingOptions"], basePath, errors, configFileName);
 
+        if (json["extends"]) {
+            let [include, exclude, files, baseOptions]: [string[], string[], string[], CompilerOptions] = [undefined, undefined, undefined, {}];
+            if (typeof json["extends"] === "string") {
+                [include, exclude, files, baseOptions] = (tryExtendsName(json["extends"]) || [include, exclude, files, baseOptions]);
+            }
+            else if (typeof json["extends"] === "object" && json["extends"].length) {
+                for (const name of json["extends"]) {
+                    const [tempinclude, tempexclude, tempfiles, tempBase]: [string[], string[], string[], CompilerOptions] = (tryExtendsName(name) || [include, exclude, files, baseOptions]);
+                    include = tempinclude || include;
+                    exclude = tempexclude || exclude;
+                    files = tempfiles || files;
+                    baseOptions = assign({}, baseOptions, tempBase);
+                }
+            }
+            else {
+                errors.push(createCompilerDiagnostic(Diagnostics.Compiler_option_0_requires_a_value_of_type_1, "extends", "string or string[]"));
+            }
+            if (include && !json["include"]) {
+                json["include"] = include;
+            }
+            if (exclude && !json["exclude"]) {
+                json["exclude"] = exclude;
+            }
+            if (files && !json["files"]) {
+                json["files"] = files;
+            }
+            options = assign({}, baseOptions, options);
+        }
+
+        options = extend(existingOptions, options);
         options.configFilePath = configFileName;
 
         const { fileNames, wildcardDirectories } = getFileNames(errors);
@@ -719,6 +761,39 @@ namespace ts {
             wildcardDirectories
         };
 
+        function tryExtendsName(extendedConfig: string): [string[], string[], string[], CompilerOptions] {
+            // If the path isn't a rooted or relative path, don't try to resolve it (we reserve the right to special case module-id like paths in the future)
+            if (!(isRootedDiskPath(extendedConfig) || startsWith(normalizeSlashes(extendedConfig), "./") || startsWith(normalizeSlashes(extendedConfig), "../"))) {
+                errors.push(createCompilerDiagnostic(Diagnostics.The_path_in_an_extends_options_must_be_relative_or_rooted));
+                return;
+            }
+            let extendedConfigPath = toPath(extendedConfig, basePath, getCanonicalFileName);
+            if (!host.fileExists(extendedConfigPath) && !endsWith(extendedConfigPath, ".json")) {
+                extendedConfigPath = `${extendedConfigPath}.json` as Path;
+                if (!host.fileExists(extendedConfigPath)) {
+                    errors.push(createCompilerDiagnostic(Diagnostics.File_0_does_not_exist, extendedConfig));
+                    return;
+                }
+            }
+            const extendedResult = readConfigFile(extendedConfigPath, path => host.readFile(path));
+            if (extendedResult.error) {
+                errors.push(extendedResult.error);
+                return;
+            }
+            const extendedDirname = getDirectoryPath(extendedConfigPath);
+            const relativeDifference = convertToRelativePath(extendedDirname, basePath, getCanonicalFileName);
+            const updatePath: (path: string) => string = path => isRootedDiskPath(path) ? path : combinePaths(relativeDifference, path);
+            // Merge configs (copy the resolution stack so it is never reused between branches in potential diamond-problem scenarios)
+            const result = parseJsonConfigFileContent(extendedResult.config, host, extendedDirname, /*existingOptions*/undefined, getBaseFileName(extendedConfigPath), resolutionStack.concat([resolvedPath]));
+            errors.push(...result.errors);
+            const [include, exclude, files] = map(["include", "exclude", "files"], key => {
+                if (!json[key] && extendedResult.config[key]) {
+                    return map(extendedResult.config[key], updatePath);
+                }
+            });
+            return [include, exclude, files, result.options];
+        }
+
         function getFileNames(errors: Diagnostic[]): ExpandResult {
             let fileNames: string[];
             if (hasProperty(json, "files")) {

src/compiler/core.ts

@@ -171,6 +171,20 @@ namespace ts {
         return result;
     }
 
+    export function mapObject<T, U>(object: Map<T>, f: (key: string, x: T) => [string, U]): Map<U> {
+        let result: Map<U> = {};
+        if (object) {
+            result = {};
+            for (const v of getKeys(object)) {
+                const [key, value]: [string, U] = f(v, object[v]) || [undefined, undefined];
+                if (key !== undefined) {
+                    result[key] = value;
+                }
+            }
+        }
+        return result;
+    }
+
     export function concatenate<T>(array1: T[], array2: T[]): T[] {
         if (!array2 || !array2.length) return array1;
         if (!array1 || !array1.length) return array2;
@@ -357,6 +371,20 @@ namespace ts {
         return result;
     }
 
+    export function assign<T1 extends Map<{}>, T2, T3>(t: T1, arg1: T2, arg2: T3): T1 & T2 & T3;
+    export function assign<T1 extends Map<{}>, T2>(t: T1, arg1: T2): T1 & T2;
+    export function assign<T1 extends Map<{}>>(t: T1, ...args: any[]): any;
+    export function assign<T1 extends Map<{}>>(t: T1, ...args: any[]) {
+        for (const arg of args) {
+            for (const p of getKeys(arg)) {
+                if (hasProperty(arg, p)) {
+                    t[p] = arg[p];
+                }
+            }
+        }
+        return t;
+    }
+
     export function forEachValue<T, U>(map: Map<T>, callback: (value: T) => U): U {
         let result: U;
         for (const id in map) {
@@ -941,7 +969,7 @@ namespace ts {
      *  [^./]                   # matches everything up to the first . character (excluding directory seperators)
      *  (\\.(?!min\\.js$))?     # matches . characters but not if they are part of the .min.js file extension
      */
-    const singleAsteriskRegexFragmentFiles = "([^./]|(\\.(?!min\\.js$))?)*";
+    const singleAsteriskRegexFragmentFiles = "([^./]|(\\.(?!min\\.js$))?)*";
     const singleAsteriskRegexFragmentOther = "[^/]*";
 
     export function getRegularExpressionForWildcard(specs: string[], basePath: string, usage: "files" | "directories" | "exclude") {

src/compiler/diagnosticMessages.json

@@ -3031,5 +3031,14 @@
     "Unknown typing option '{0}'.": {
         "category": "Error",
         "code": 17010
+    },
+
+    "Circularity detected while resolving configuration: {0}": {
+        "category": "Error",
+        "code": 18000
+    },
+    "The path in an 'extends' options must be relative or rooted.": {
+        "category": "Error",
+        "code": 18001
     }
 }

src/compiler/types.ts

@@ -1693,6 +1693,8 @@ namespace ts {
           * @param path The path to test.
           */
         fileExists(path: string): boolean;
+
+        readFile(path: string): string;
     }
 
     export interface WriteFileCallback {

src/harness/harness.ts

@@ -1540,7 +1540,8 @@ namespace Harness {
             const parseConfigHost: ts.ParseConfigHost = {
                 useCaseSensitiveFileNames: false,
                 readDirectory: (name) => [],
-                fileExists: (name) => true
+                fileExists: (name) => true,
+                readFile: (name) => ts.forEach(testUnitData, data => data.name.toLowerCase() === name.toLowerCase() ? data.content : undefined)
             };
 
             // check if project has tsconfig.json in the list of files

src/harness/projectsRunner.ts

@@ -222,6 +222,7 @@ class ProjectRunner extends RunnerBase {
                     useCaseSensitiveFileNames: Harness.IO.useCaseSensitiveFileNames(),
                     fileExists,
                     readDirectory,
+                    readFile
                 };
                 const configParseResult = ts.parseJsonConfigFileContent(configObject, configParseHost, ts.getDirectoryPath(configFileName), compilerOptions);
                 if (configParseResult.errors.length > 0) {
@@ -295,6 +296,10 @@ class ProjectRunner extends RunnerBase {
                 return Harness.IO.fileExists(getFileNameInTheProjectTest(fileName));
             }
 
+            function readFile(fileName: string): string {
+                return Harness.IO.readFile(getFileNameInTheProjectTest(fileName));
+            }
+
             function getSourceFileText(fileName: string): string {
                 let text: string = undefined;
                 try {

src/harness/rwcRunner.ts

@@ -79,6 +79,7 @@ namespace RWC {
                             useCaseSensitiveFileNames: Harness.IO.useCaseSensitiveFileNames(),
                             fileExists: Harness.IO.fileExists,
                             readDirectory: Harness.IO.readDirectory,
+                            readFile: Harness.IO.readFile
                         };
                         const configParseResult = ts.parseJsonConfigFileContent(parsedTsconfigFileContents.config, configParseHost, ts.getDirectoryPath(tsconfigFile.path));
                         fileNames = configParseResult.fileNames;

src/harness/tsconfig.json

@@ -86,6 +86,7 @@
         "./unittests/moduleResolution.ts",
         "./unittests/tsconfigParsing.ts",
         "./unittests/commandLineParsing.ts",
+        "./unittests/configurationExtension.ts",
         "./unittests/convertCompilerOptionsFromJson.ts",
         "./unittests/convertTypingOptionsFromJson.ts",
         "./unittests/tsserverProjectSystem.ts",