support paths without baseUrl for TS 6.0+ compatibility

RealColdFry · RealColdFry · commit a4c79be10531 · 2026-03-30T01:10:24.000+01:00
diff --git a/package.json b/package.json
@@ -31,7 +31,7 @@
         "lint:prettier": "prettier --check . || (echo 'Run `npm run fix:prettier` to fix it.' && exit 1)",
         "lint:eslint": "eslint .",
         "fix:prettier": "prettier --write .",
-        "check:language-extensions": "tsc --strict language-extensions/index.d.ts",
+        "check:language-extensions": "tsc --strict --ignoreConfig language-extensions/index.d.ts",
         "preversion": "npm run build && npm test",
         "postversion": "git push && git push --tags"
     },
diff --git a/src/CompilerOptions.ts b/src/CompilerOptions.ts
@@ -99,9 +99,7 @@ export function validateOptions(options: CompilerOptions): ts.Diagnostic[] {
         diagnostics.push(diagnosticFactories.unsupportedJsxEmit());
     }
 
-    if (options.paths && !options.baseUrl) {
-        diagnostics.push(diagnosticFactories.pathsWithoutBaseUrl());
-    }
+    // paths without baseUrl is now supported (TS 6.0+ resolves paths relative to tsconfig location)
 
     return diagnostics;
 }
diff --git a/src/transpilation/resolve.ts b/src/transpilation/resolve.ts
@@ -215,14 +215,19 @@ class ResolutionContext {
         const fileFromPath = this.getFileFromPath(resolvedPath);
         if (fileFromPath) return fileFromPath;
 
-        if (this.options.paths && this.options.baseUrl) {
+        if (this.options.paths) {
             // If no file found yet and paths are present, try to find project file via paths mappings
-            const fileFromPaths = this.tryGetModuleNameFromPaths(
-                dependencyPath,
-                this.options.paths,
-                this.options.baseUrl
-            );
-            if (fileFromPaths) return fileFromPaths;
+            // When baseUrl is not set, resolve paths relative to the tsconfig directory (TS 6.0+ behavior)
+            const pathsBase = this.options.baseUrl
+                ?? (this.options.configFilePath ? path.dirname(this.options.configFilePath) : undefined);
+            if (pathsBase) {
+                const fileFromPaths = this.tryGetModuleNameFromPaths(
+                    dependencyPath,
+                    this.options.paths,
+                    pathsBase
+                );
+                if (fileFromPaths) return fileFromPaths;
+            }
         }
 
         // Not a TS file in our project sources, use resolver to check if we can find dependency
diff --git a/test/transpile/module-resolution.spec.ts b/test/transpile/module-resolution.spec.ts
@@ -4,7 +4,6 @@ import * as util from "../util";
 import * as ts from "typescript";
 import { BuildMode } from "../../src";
 import { normalizeSlashes } from "../../src/utils";
-import { pathsWithoutBaseUrl } from "../../src/transpilation/diagnostics";
 
 describe("basic module resolution", () => {
     const projectPath = path.resolve(__dirname, "module-resolution", "project-with-node-modules");
@@ -711,8 +710,21 @@ test("supports complicated paths configuration", () => {
         .expectToEqual({ foo: 314, bar: 271 });
 });
 
-test("paths without baseUrl is error", () => {
-    util.testFunction``.setOptions({ paths: {} }).expectToHaveDiagnostics([pathsWithoutBaseUrl.code]);
+test("paths without baseUrl is not an error", () => {
+    util.testFunction``.setOptions({ paths: {} }).expectToHaveNoDiagnostics();
+});
+
+test("supports paths configuration without baseUrl", () => {
+    const baseProjectPath = path.resolve(__dirname, "module-resolution", "paths-no-baseurl");
+    const projectPath = path.join(baseProjectPath, "myprogram");
+    const projectTsConfig = path.join(projectPath, "tsconfig.json");
+    const mainFile = path.join(projectPath, "main.ts");
+
+    // Bundle to have all files required to execute and check result
+    util.testProject(projectTsConfig)
+        .setMainFileName(mainFile)
+        .setOptions({ luaBundle: "bundle.lua", luaBundleEntry: mainFile })
+        .expectToEqual({ foo: 314, bar: 271 });
 });
 
 test("module resolution using plugin", () => {
diff --git a/test/transpile/module-resolution/paths-no-baseurl/mypackage/bar.ts b/test/transpile/module-resolution/paths-no-baseurl/mypackage/bar.ts
@@ -0,0 +1 @@
+export const bar = 271;
diff --git a/test/transpile/module-resolution/paths-no-baseurl/mypackage/index.ts b/test/transpile/module-resolution/paths-no-baseurl/mypackage/index.ts
@@ -0,0 +1 @@
+export const foo = 314;
diff --git a/test/transpile/module-resolution/paths-no-baseurl/myprogram/main.ts b/test/transpile/module-resolution/paths-no-baseurl/myprogram/main.ts
@@ -0,0 +1,4 @@
+import { foo } from "myOtherPackage";
+import { bar } from "myOtherPackage/bar";
+
+export { foo, bar };
diff --git a/test/transpile/module-resolution/paths-no-baseurl/myprogram/tsconfig.json b/test/transpile/module-resolution/paths-no-baseurl/myprogram/tsconfig.json
@@ -0,0 +1,10 @@
+{
+    "compilerOptions": {
+        "rootDir": "..",
+        "outDir": "dist",
+        "paths": {
+            "myOtherPackage": ["../mypackage"],
+            "myOtherPackage/*": ["../mypackage/*"]
+        }
+    }
+}

Original file line number	Diff line number	Diff line change
`@@ -99,9 +99,7 @@ export function validateOptions(options: CompilerOptions): ts.Diagnostic[] {`
`99`	`99`	`diagnostics.push(diagnosticFactories.unsupportedJsxEmit());`
`100`	`100`	`}`
`101`	`101`
`102`		`- if (options.paths && !options.baseUrl) {`
`103`		`- diagnostics.push(diagnosticFactories.pathsWithoutBaseUrl());`
`104`		`- }`
	`102`	`+ // paths without baseUrl is now supported (TS 6.0+ resolves paths relative to tsconfig location)`
`105`	`103`
`106`	`104`	`return diagnostics;`
`107`	`105`	`}`