fix: Handle relative paths in source maps correctly

package.json

@@ -70,7 +70,6 @@
     "acorn-walk": "^8.2.0",
     "astring": "^1.8.6",
     "chalk": "<5",
-    "convert-source-map": "^2.0.0",
     "meriyah": "^4.3.7",
     "source-map-js": "^1.0.2",
     "strip-json-comments": "^3",

src/transform.ts

@@ -1,11 +1,11 @@
 import assert from "node:assert";
 import { readFileSync, writeFileSync } from "node:fs";
+import { dirname } from "node:path";
 import { URL, fileURLToPath } from "node:url";
 import { debuglog } from "node:util";
 import { isNativeError } from "node:util/types";
 
 import { generate } from "astring";
-import * as SourceMapConverter from "convert-source-map";
 import { parse, type ESTree } from "meriyah";
 import { RawSourceMap, SourceMapConsumer } from "source-map-js";
 
@@ -64,34 +64,28 @@ function dumpTree(xformed: ESTree.Program, url: URL) {
   treeDebug("wrote transformed tree to %s", path);
 }
 
-function getSourceMap(url: URL, code: string): SourceMapConsumer | undefined {
-  if (
-    process.versions.node.split(".").map(Number) < [18, 19] &&
-    [".ts", ".mts", ".tsx"].some((e) => url.pathname.toLowerCase().endsWith(e))
-  ) {
-    // HACK: In node 18.18, when using --loader node-ts/esm
-    // sourcemap gets inserted twice to the typescript file. We remove the second one
-    // which reflects transpiled files map, instead of the original typescript file map.
-    code = SourceMapConverter.removeComments(code);
-    if (code.indexOf("//# sourceMappingURL") > -1)
-      // Correct one remains, it needs to start in new line.
-      code.replace("//# sourceMappingURL", "\n//# sourceMappingURL");
-  }
+function getSourceMap(fileUrl: URL, code: string): SourceMapConsumer | undefined {
+  const sourceMappingUrl = code.match(/\/\/# sourceMappingURL=(.*)/)?.[1];
+  if (!sourceMappingUrl) return;
 
-  const readFile = (filename: string) => {
-    const fileUrl = new URL(filename, url);
-    switch (fileUrl.protocol) {
-      case "file:":
-        return readFileSync(fileUrl, "utf8");
-      case "data:":
-        return parseDataUrl(fileUrl);
-      default:
-        throw new Error(`unhandled protocol reading source map: ${fileUrl.protocol}`);
-    }
-  };
+  const sourceMapUrl = new URL(sourceMappingUrl, fileUrl);
+
+  let sourceMap: RawSourceMap;
+
+  switch (sourceMapUrl.protocol) {
+    case "data:":
+      sourceMap = JSON.parse(parseDataUrl(sourceMapUrl)) as RawSourceMap;
+      break;
+    case "file:":
+      fileUrl = sourceMapUrl;
+      sourceMap = JSON.parse(readFileSync(fileURLToPath(sourceMapUrl), "utf8")) as RawSourceMap;
+      break;
+    default:
+      throw new Error(`Unsupported source map protocol: ${sourceMapUrl.protocol}`);
+  }
 
-  const map = SourceMapConverter.fromMapFileSource(code, readFile);
-  if (map) return new SourceMapConsumer(map.sourcemap as RawSourceMap);
+  sourceMap.sourceRoot ||= dirname(fileURLToPath(fileUrl));
+  return new SourceMapConsumer(sourceMap);
 }
 
 function parseDataUrl(fileUrl: URL) {

test/__snapshots__/typescript-esm.test.ts.snap

@@ -8,7 +8,7 @@ exports[`esm-loader is loaded when required 1`] = `
         {
           "children": [
             {
-              "location": "index.ts:1",
+              "location": "src/index.ts:1",
               "name": "run",
               "static": true,
               "type": "function",
@@ -18,7 +18,7 @@ exports[`esm-loader is loaded when required 1`] = `
           "type": "class",
         },
       ],
-      "name": "appmap-node-typescript-esm-test",
+      "name": "src",
       "type": "package",
     },
   ],
@@ -30,7 +30,7 @@ exports[`esm-loader is loaded when required 1`] = `
       "lineno": 1,
       "method_id": "run",
       "parameters": [],
-      "path": "index.ts",
+      "path": "src/index.ts",
       "static": true,
       "thread_id": 0,
     },

test/typescript-esm.test.ts

@@ -4,17 +4,17 @@ import { spawnSync } from "node:child_process";
 import { integrationTest, readAppmap, resolveTarget, runAppmapNode } from "./helpers";
 
 integrationTest("esm-loader is loaded when required", () => {
-  expect(runAppmapNode("node", "--loader", "ts-node/esm", "index.ts").status).toBe(0);
+  expect(runAppmapNode("node", "--loader", "ts-node/esm", "src/index.ts").status).toBe(0);
   expect(readAppmap()).toMatchSnapshot();
 });
 
 integrationTest("appmap-node uses external source maps", () => {
   expect(
     spawnSync("yarn", ["tsc"], { cwd: resolveTarget(), shell: true, stdio: "inherit" }).status,
   ).toBe(0);
-  expect(runAppmapNode("index.js").status).toBe(0);
+  expect(runAppmapNode("dist/index.js").status).toBe(0);
   const appMap = readAppmap();
   const fun = appMap.classMap.at(0)?.children?.at(0)?.children?.at(0);
   assert(fun?.type === "function");
-  expect(fun.location).toContain("index.ts");
+  expect(fun.location).toMatch(/^src\/index.ts:/);
 });

test/typescript-esm/tsconfig.json

@@ -2,11 +2,12 @@
   "ts-node": {
     "esm": true
   },
-  "files": ["index.ts"],
+  "files": ["src/index.ts"],
   "compilerOptions": {
     "strictNullChecks": true,
     "module": "ESNext" /* Specify what module code is generated. */,
-    "rootDir": "./" /* Specify the root folder within your source files. */,
+    "rootDir": "src" /* Specify the root folder within your source files. */,
+    "outDir": "dist",
     "types": ["node"],
     "sourceMap": true
   }

yarn.lock

@@ -2669,7 +2669,6 @@ __metadata:
     astring: ^1.8.6
     caller: ^1.1.0
     chalk: <5
-    convert-source-map: ^2.0.0
     eslint: ^8.47.0
     eslint-config-prettier: ^9.0.0
     eslint-plugin-prettier: ^5.0.1