Fix bug outputting files to the wrong location in some cases (#1541)

src/transpilation/transpiler.ts

@@ -203,7 +203,9 @@ export function getSourceDir(program: ts.Program): string {
     if (rootDir && rootDir.length > 0) {
         return path.isAbsolute(rootDir) ? rootDir : path.resolve(getProjectRoot(program), rootDir);
     }
-    return program.getCommonSourceDirectory();
+
+    // If no rootDir is given, source is relative to the project root
+    return getProjectRoot(program);
 }
 
 export function getEmitOutDir(program: ts.Program): string {

test/transpile/__snapshots__/module-resolution.spec.ts.snap

@@ -10,8 +10,8 @@ exports[`supports complicated paths configuration 1`] = `
 
 exports[`supports paths configuration 1`] = `
 [
+  "/paths-simple/myprogram/dist/main.lua",
   "/paths-simple/myprogram/dist/mypackage/bar.lua",
   "/paths-simple/myprogram/dist/mypackage/index.lua",
-  "/paths-simple/myprogram/dist/myprogram/main.lua",
 ]
 `;

test/transpile/paths.spec.ts

@@ -1,6 +1,6 @@
 import * as path from "path";
 import * as ts from "typescript";
-import { getSourceDir } from "../../src";
+import { getEmitPath, getSourceDir } from "../../src";
 import * as util from "../util";
 
 const cwd = process.cwd();
@@ -12,31 +12,24 @@ describe("getSourceDir", () => {
     test("with rootDir", () => {
         const program = ts.createProgram(["main.ts", "src/otherfile.ts"], { configFilePath, rootDir: "src" });
 
-        // getCommonSourceDirectory does not work right so mock it
-        jest.spyOn(program, "getCommonSourceDirectory").mockReturnValue(cwd);
-
+        // If rootdir is specified, rootDir is the sourceDir
         expect(getSourceDir(program)).toBe(path.join(cwd, "src"));
     });
 
     test("without rootDir", () => {
         const program = ts.createProgram(["main.ts", "src/otherfile.ts"], { configFilePath });
 
-        // getCommonSourceDirectory does not work right so mock it
-        jest.spyOn(program, "getCommonSourceDirectory").mockReturnValue(cwd);
-
-        // Common sources directory is project root
+        // If rootDir is not specified, root dir is where the config file is
         expect(normalize(getSourceDir(program))).toBe(cwd);
     });
 
-    test("without rootDir in src dir", () => {
-        const program = ts.createProgram([path.join(cwd, "src", "main.ts"), path.join(cwd, "src", "otherfile.ts")], {
-            configFilePath,
-        });
+    test("without config file in src dir", () => {
+        const program = ts.createProgram([path.join(cwd, "src", "main.ts"), path.join(cwd, "src", "otherfile.ts")], {});
 
         // getCommonSourceDirectory does not work right so mock it
         jest.spyOn(program, "getCommonSourceDirectory").mockReturnValue(path.join(cwd, "src"));
 
-        // Common sources directory is src
+        // If there is no config file, return the common source directory
         expect(normalize(getSourceDir(program))).toBe(path.join(cwd, "src"));
     });
 });
@@ -145,6 +138,21 @@ describe("getEmitPath", () => {
         expect(fileNames).toHaveLength(1);
         expect(fileNames).toContain(path.join(cwd, "out1", "out2", "bundle.scar"));
     });
+
+    // https://github.com/TypeScriptToLua/TypeScriptToLua/issues/1540
+    test("puts files next to their source if no config is given (#1540)", () => {
+        const file1 = path.join("src", "main.ts");
+        const file2 = path.join("src", "otherfile.ts");
+        const file3 = path.join("src", "nested", "nestedfile.ts");
+        const program = ts.createProgram([file1, file2, file3], { configFilePath });
+
+        // If rootDir is not specified, root dir is where the config file is
+        const configRoot = path.dirname(configFilePath);
+        const replaceExtension = (f: string) => f.replace(/\.ts$/, ".lua");
+        expect(getEmitPath(file1, program)).toBe(replaceExtension(path.join(configRoot, file1)));
+        expect(getEmitPath(file2, program)).toBe(replaceExtension(path.join(configRoot, file2)));
+        expect(getEmitPath(file3, program)).toBe(replaceExtension(path.join(configRoot, file3)));
+    });
 });
 
 function normalize(path: string) {