TypeScriptToLua · Perryvw · May 2, 2023 · May 1, 2023 · May 1, 2023 · May 1, 2023
diff --git a/src/cli/tsconfig.ts b/src/cli/tsconfig.ts
@@ -1,6 +1,6 @@
 import * as path from "path";
 import * as ts from "typescript";
-import { CompilerOptions } from "../CompilerOptions";
+import { CompilerOptions, TypeScriptToLuaOptions } from "../CompilerOptions";
 import { normalizeSlashes } from "../utils";
 import * as cliDiagnostics from "./diagnostics";
 import { ParsedCommandLine, updateParsedConfigFile } from "./parse";
@@ -41,17 +41,73 @@ export function parseConfigFileWithSystem(
     commandLineOptions?: CompilerOptions,
     system = ts.sys
 ): ParsedCommandLine {
+    const configRootDir = path.dirname(configFileName);
     const parsedConfigFile = ts.parseJsonSourceFileConfigFileContent(
         ts.readJsonConfigFile(configFileName, system.readFile),
         system,
-        path.dirname(configFileName),
+        configRootDir,
         commandLineOptions,
         configFileName
     );
 
+    const cycleCache = new Set<string>();
+    const extendedTstlOptions = getExtendedTstlOptions(configFileName, configRootDir, cycleCache, system);
+
+    parsedConfigFile.raw.tstl = Object.assign(extendedTstlOptions, parsedConfigFile.raw.tstl ?? {});
+
     return updateParsedConfigFile(parsedConfigFile);
 }
 
+function getExtendedTstlOptions(
+    configFilePath: string,
+    configRootDir: string,
+    cycleCache: Set<string>,
+    system: ts.System
+): TypeScriptToLuaOptions {
+    const absolutePath = path.isAbsolute(configFilePath) ? configFilePath : path.resolve(configRootDir, configFilePath);
+    const newConfigRoot = path.dirname(absolutePath);
+
+    if (cycleCache.has(absolutePath)) {
+        return {};
+    }
+
+    cycleCache.add(absolutePath);
+    const fileContent = system.readFile(absolutePath);
+    const options = {};
+
+    if (fileContent) {
+        const { config: parsedConfig } = ts.parseConfigFileTextToJson(configFilePath, fileContent) as {
+            config?: {
+                extends?: string | string[];
+                tstl?: TypeScriptToLuaOptions;
+            };
+        };
+
+        if (!parsedConfig) {
+            return {};
+        }
+
+        if (parsedConfig.extends) {
+            if (Array.isArray(parsedConfig.extends)) {
+                for (const extendedConfigFile of parsedConfig.extends) {
+                    Object.assign(
+                        options,
+                        getExtendedTstlOptions(extendedConfigFile, newConfigRoot, cycleCache, system)
+                    );
+                }
+            } else {
+                Object.assign(options, getExtendedTstlOptions(parsedConfig.extends, newConfigRoot, cycleCache, system));
+            }
+        }
+
+        if (parsedConfig.tstl) {
+            Object.assign(options, parsedConfig.tstl);
+        }
+    }
+
+    return options;
+}
+
 export function createConfigFileUpdater(
     optionsToExtend: CompilerOptions
 ): (options: ts.CompilerOptions) => ts.Diagnostic[] {

diff --git a/test/cli/tsconfig.spec.ts b/test/cli/tsconfig.spec.ts
@@ -1,7 +1,7 @@
 import * as fs from "fs-extra";
 import * as os from "os";
 import * as path from "path";
-import { locateConfigFile } from "../../src/cli/tsconfig";
+import { locateConfigFile, parseConfigFileWithSystem } from "../../src/cli/tsconfig";
 import { normalizeSlashes } from "../../src/utils";
 
 let temp: string;
@@ -91,3 +91,25 @@ describe("errors", () => {
         expect([locate("tsconfig.json", [""])]).toHaveDiagnostics();
     });
 });
+
+describe("tsconfig extends", () => {
+    test("correctly merges extended tsconfig files", () => {
+        const parsedConfig = parseConfigFileWithSystem(path.join(__dirname, "tsconfig", "tsconfig.json"));
+        expect(parsedConfig.options).toMatchObject({ luaTarget: "5.3", noHeader: true });
+    });
+
+    test("can handle multiple extends", () => {
+        const parsedConfig = parseConfigFileWithSystem(path.join(__dirname, "tsconfig", "tsconfig.multi-extends.json"));
+        expect(parsedConfig.options).toMatchObject({ luaTarget: "5.4", sourceMapTraceback: true });
+    });
+
+    test("can handle cycles in configs", () => {
+        const parsedConfig = parseConfigFileWithSystem(path.join(__dirname, "tsconfig", "tsconfig-cycle1.json"));
+        expect(parsedConfig.options).toMatchObject({ luaTarget: "5.4" });
+    });
+
+    test("can handle tsconfig files with comments", () => {
+        const parsedConfig = parseConfigFileWithSystem(path.join(__dirname, "tsconfig", "tsconfig.with-comments.json"));
+        expect(parsedConfig.options).toMatchObject({ luaTarget: "5.3" });
+    });
+});
diff --git a/test/cli/tsconfig/tsconfig-cycle1.json b/test/cli/tsconfig/tsconfig-cycle1.json
@@ -0,0 +1,6 @@
+{
+    "extends": "./tsconfig-cycle2.json",
+    "tstl": {
+        "luaTarget": "5.4"
+    }
+}
diff --git a/test/cli/tsconfig/tsconfig-cycle2.json b/test/cli/tsconfig/tsconfig-cycle2.json
@@ -0,0 +1,6 @@
+{
+    "extends": "./tsconfig-cycle1.json",
+    "tstl": {
+        "luaTarget": "5.3"
+    }
+}
diff --git a/test/cli/tsconfig/tsconfig.base.json b/test/cli/tsconfig/tsconfig.base.json
@@ -0,0 +1,6 @@
+{
+    "tstl": {
+        "noHeader": true,
+        "luaTarget": "jit"
+    }
+}
diff --git a/test/cli/tsconfig/tsconfig.json b/test/cli/tsconfig/tsconfig.json
@@ -0,0 +1,6 @@
+{
+    "extends": "./tsconfig.base.json",
+    "tstl": {
+        "luaTarget": "5.3"
+    }
+}
diff --git a/test/cli/tsconfig/tsconfig.multi-extends.json b/test/cli/tsconfig/tsconfig.multi-extends.json
@@ -0,0 +1,6 @@
+{
+    "extends": ["./tsconfig.json", "./tsconfig2.json"],
+    "tstl": {
+        "sourceMapTraceback": true
+    }
+}
diff --git a/test/cli/tsconfig/tsconfig.with-comments.json b/test/cli/tsconfig/tsconfig.with-comments.json
@@ -0,0 +1,8 @@
+{
+    "extends": "./tsconfig.base.json",
+    "tstl": {
+        // Can handle comments
+        /* also of this kind */
+        "luaTarget": "5.3"
+    }
+}
diff --git a/test/cli/tsconfig/tsconfig2.json b/test/cli/tsconfig/tsconfig2.json
@@ -0,0 +1,5 @@
+{
+    "tstl": {
+        "luaTarget": "5.4"
+    }
+}