use built-in source map support in node v20

The @cspotcode/source-map-support module does not function properly on
Node 20, resulting in incorrect stack traces. Fortunately, the built-in
source map support in Node is now quite reliable. This does have the
following (somewhat subtle) changes to error output:

- When a call site is in a method defined within a constructor function,
  it picks up the function name *as well as* the type name and method
  name. So, in tests where a method is called and throws within the a
  function constructor, we see `Foo.Foo.bar` instead of `Foo.bar`.
- Call sites displays show filenames instead of file URLs.
- The call site display puts the `^` character under the `throw` rather
  than the construction point of the error object. This is closer to how
  normal un-transpiled JavaScript behaves, and thus somewhat
  preferrable, but isn't possible when all we have to go on is the Error
  stack property, so it is a change.

I haven't been able to figure out why exactly, but the call sites appear
to be somewhat different in the repl/eval contexts as a result of this
change. It almost seems like the @cspotcode/source-map-support was
applying source maps to the vm-evaluated scripts, but I don't see how
that could be, and in fact, there's a comment in the code stating that
that *isn't* the case. But the line number showing up in an Error.stack
property is `1` prior to this change (matching the location in the TS
source) and is `2` afterwards (matching the location in the compiled
JS).

An argument could be made that specific line numbers are a bit
meaningless in a REPL anyway, and the best approach is to just make
those tests accept either result. One possible approach to provide
built-in source map support for the repl would be to refactor the
`appendCompileAndEvalInput` to diff and append the *input* TS, and
compile within the `runInContext` method. If the transpiled code was
prepended with `process.setSourceMapsEnabled(true);`, then Error stacks
and call sites would be properly source mapped by Node internally.

Author: isaacs

src/index.ts

@@ -691,7 +691,13 @@ export function createFromPreloadedConfig(foundConfigResult: ReturnType<typeof f
   }
 
   // Install source map support and read from memory cache.
+  const useBuiltInSourceMaps = versionGteLt(process.versions.node, '20.0.0');
   function installSourceMapSupport() {
+    if (useBuiltInSourceMaps) {
+      //@ts-ignore added to node somewhat recently, not yet in DT.
+      process.setSourceMapsEnabled(true);
+      return;
+    }
     const sourceMapSupport = require('@cspotcode/source-map-support') as typeof _sourceMapSupport;
     sourceMapSupport.install({
       environment: 'node',

src/test/esm-loader.spec.ts

@@ -25,6 +25,7 @@ import { join, resolve } from 'path';
 import * as expect from 'expect';
 import type { NodeLoaderHooksAPI2 } from '../';
 import { pathToFileURL } from 'url';
+import { versionGteLt } from '../util';
 
 const test = context(ctxTsNode);
 
@@ -48,16 +49,18 @@ test.suite('esm', (test) => {
       cwd: join(TEST_DIR, './esm'),
     });
     expect(r.err).not.toBe(null);
-    const expectedModuleUrl = pathToFileURL(join(TEST_DIR, './esm/throw error.ts')).toString();
+    // on node 20, this will be a path. prior versions, a file: url
+    const expectedModulePath = join(TEST_DIR, './esm/throw error.ts');
+    const expectedModuleUrl = pathToFileURL(expectedModulePath).toString();
+    const expectedModulePrint = versionGteLt(process.versions.node, '20.0.0') ? expectedModulePath : expectedModuleUrl;
     expect(r.err!.message).toMatch(
-      [
-        `${expectedModuleUrl}:100`,
-        "  bar() { throw new Error('this is a demo'); }",
-        '                ^',
-        'Error: this is a demo',
-        `    at Foo.bar (${expectedModuleUrl}:100:17)`,
-      ].join('\n')
+      [`${expectedModulePrint}:100`, "  bar() { throw new Error('this is a demo'); }"].join('\n')
     );
+    // the ^ and number of line-breaks is platform-specific
+    // also, node 20 puts the type in here when source mapping it, so it
+    // shows as Foo.Foo.bar
+    expect(r.err!.message).toMatch(/^    at (Foo\.){1,2}bar \(/m);
+    expect(r.err!.message).toMatch(`Foo.bar (${expectedModulePrint}:100:17)`);
   });
 
   test.suite('supports experimental-specifier-resolution=node', (test) => {
@@ -95,7 +98,7 @@ test.suite('esm', (test) => {
     });
     expect(r.err).not.toBe(null);
     // expect error from node's default resolver
-    expect(r.stderr).toMatch(/Error \[ERR_UNSUPPORTED_ESM_URL_SCHEME\]:.*(?:\n.*){0,2}\n *at default(Load|Resolve)/);
+    expect(r.stderr).toMatch(/Error \[ERR_UNSUPPORTED_ESM_URL_SCHEME\]:.*(?:\n.*){0,10}\n *at default(Load|Resolve)/);
   });
 
   test('should bypass import cache when changing search params', async () => {

src/test/index.spec.ts

@@ -182,12 +182,7 @@ test.suite('ts-node', (test) => {
       }
 
       expect(r.err.message).toMatch(
-        [
-          `${join(TEST_DIR, 'throw error.ts')}:100`,
-          "  bar() { throw new Error('this is a demo'); }",
-          '                ^',
-          'Error: this is a demo',
-        ].join('\n')
+        [`${join(TEST_DIR, 'throw error.ts')}:100`, "  bar() { throw new Error('this is a demo'); }"].join('\n')
       );
     });
 
@@ -198,12 +193,7 @@ test.suite('ts-node', (test) => {
       }
 
       expect(r.err.message).toMatch(
-        [
-          `${join(TEST_DIR, 'throw error.ts')}:100`,
-          "  bar() { throw new Error('this is a demo'); }",
-          '                ^',
-          'Error: this is a demo',
-        ].join('\n')
+        [`${join(TEST_DIR, 'throw error.ts')}:100`, "  bar() { throw new Error('this is a demo'); }"].join('\n')
       );
     });
 
@@ -214,11 +204,7 @@ test.suite('ts-node', (test) => {
       }
 
       expect(r.err.message).toMatch(
-        [
-          `${join(TEST_DIR, 'throw error.ts')}:100`,
-          "  bar() { throw new Error('this is a demo'); }",
-          '                ^',
-        ].join('\n')
+        [`${join(TEST_DIR, 'throw error.ts')}:100`, "  bar() { throw new Error('this is a demo'); }"].join('\n')
       );
     });
 
@@ -309,25 +295,19 @@ test.suite('ts-node', (test) => {
       const r = await exec(`${CMD_TS_NODE_WITH_PROJECT_FLAG} "throw error react tsx.tsx"`);
       expect(r.err).not.toBe(null);
       expect(r.err!.message).toMatch(
-        [
-          `${join(TEST_DIR, './throw error react tsx.tsx')}:100`,
-          "  bar() { throw new Error('this is a demo'); }",
-          '                ^',
-          'Error: this is a demo',
-        ].join('\n')
+        [`${join(TEST_DIR, './throw error react tsx.tsx')}:100`, "  bar() { throw new Error('this is a demo'); }"].join(
+          '\n'
+        )
       );
     });
 
     test('should use source maps with react tsx in --transpile-only mode', async () => {
       const r = await exec(`${CMD_TS_NODE_WITH_PROJECT_FLAG} --transpile-only "throw error react tsx.tsx"`);
       expect(r.err).not.toBe(null);
       expect(r.err!.message).toMatch(
-        [
-          `${join(TEST_DIR, './throw error react tsx.tsx')}:100`,
-          "  bar() { throw new Error('this is a demo'); }",
-          '                ^',
-          'Error: this is a demo',
-        ].join('\n')
+        [`${join(TEST_DIR, './throw error react tsx.tsx')}:100`, "  bar() { throw new Error('this is a demo'); }"].join(
+          '\n'
+        )
       );
     });
 

src/test/sourcemaps.spec.ts

@@ -1,4 +1,5 @@
 import * as expect from 'expect';
+import { versionGteLt } from '../util';
 import { createExec, createExecTester, CMD_TS_NODE_WITH_PROJECT_FLAG, ctxTsNode, TEST_DIR } from './helpers';
 import { context } from './testlib';
 const test = context(ctxTsNode);
@@ -10,17 +11,23 @@ const exec = createExecTester({
   }),
 });
 
-test('Redirects source-map-support to @cspotcode/source-map-support so that third-party libraries get correct source-mapped locations', async () => {
-  const r = await exec({
-    flags: `./legacy-source-map-support-interop/index.ts`,
+const useBuiltInSourceMaps = versionGteLt(process.versions.node, '20.0.0');
+
+if (useBuiltInSourceMaps) {
+  test.skip('Skip source-map-support redirection on node 20', () => {});
+} else {
+  test('Redirects source-map-support to @cspotcode/source-map-support so that third-party libraries get correct source-mapped locations', async () => {
+    const r = await exec({
+      flags: `./legacy-source-map-support-interop/index.ts`,
+    });
+    expect(r.err).toBeNull();
+    expect(r.stdout.split('\n')).toMatchObject([
+      expect.stringContaining('.ts:2 '),
+      'true',
+      'true',
+      expect.stringContaining('.ts:100:'),
+      expect.stringContaining('.ts:101 '),
+      '',
+    ]);
   });
-  expect(r.err).toBeNull();
-  expect(r.stdout.split('\n')).toMatchObject([
-    expect.stringContaining('.ts:2 '),
-    'true',
-    'true',
-    expect.stringContaining('.ts:100:'),
-    expect.stringContaining('.ts:101 '),
-    '',
-  ]);
-});
+}