build-system: reorganize sourcemap logic (#37482)

* build-system: reorganize sourcemap logic

* lint

build-system/tasks/helpers.js

@@ -6,7 +6,6 @@ const experimentDefines = require('../global-configs/experiments-const.json');
 const fs = require('fs-extra');
 const open = require('open');
 const path = require('path');
-const Remapping = require('@ampproject/remapping');
 const terser = require('terser');
 const wrappers = require('../compile/compile-wrappers');
 const {
@@ -16,16 +15,13 @@ const {cyan, green, red} = require('kleur/colors');
 const {generateBentoRuntimeEntrypoint} = require('../compile/generate/bento');
 const {getAmpConfigForFile} = require('./prepend-global');
 const {getEsbuildBabelPlugin} = require('../common/esbuild-babel');
-const {getSourceRoot} = require('../compile/helpers');
+const {massageSourcemaps} = require('./sourcemaps');
 const {isCiBuild} = require('../common/ci');
 const {jsBundles} = require('../compile/bundles.config');
 const {log, logLocalDev} = require('../common/logging');
 const {thirdPartyFrames} = require('../test-configs/config');
 const {watch} = require('chokidar');
 
-/** @type {Remapping.default} */
-const remapping = /** @type {*} */ (Remapping);
-
 /**
  * Tasks that should print the `--nobuild` help text.
  * @private @const {!Set<string>}
@@ -696,52 +692,6 @@ async function getDependencies(entryPoint, options) {
   return Object.keys(result.metafile?.inputs ?? {});
 }
 
-/**
- * @param {!Array<string|object>} sourcemaps
- * @param {Map<string, string|object>} babelMaps
- * @param {*} options
- * @return {string}
- */
-function massageSourcemaps(sourcemaps, babelMaps, options) {
-  const root = process.cwd();
-  const remapped = remapping(
-    sourcemaps,
-    (f) => {
-      if (f.includes('__SOURCE__')) {
-        return null;
-      }
-      const file = path.join(root, f);
-      // The Babel tranformed file and the original file have the same path,
-      // which makes it difficult to distinguish during remapping's load phase.
-      // We perform some manual path mangling to destingish the babel files
-      // (which have a sourcemap) from the actual source file by pretending the
-      // source file exists in the '__SOURCE__' root directory.
-      const map = babelMaps.get(file);
-      if (!map) {
-        throw new Error(`failed to find sourcemap for babel file "${f}"`);
-      }
-      return {
-        ...map,
-        sourceRoot: path.posix.join('/__SOURCE__/', path.dirname(f)),
-      };
-    },
-    !argv.full_sourcemaps
-  );
-
-  remapped.sources = remapped.sources.map((source) => {
-    if (source?.startsWith('/__SOURCE__/')) {
-      return source.slice('/__SOURCE__/'.length);
-    }
-    return source;
-  });
-  remapped.sourceRoot = getSourceRoot(options);
-  if (remapped.file) {
-    remapped.file = path.basename(remapped.file);
-  }
-
-  return remapped.toString();
-}
-
 module.exports = {
   bootstrapThirdPartyFrames,
   compileAllJs,

build-system/tasks/sourcemaps.js

@@ -0,0 +1,78 @@
+const argv = require('minimist')(process.argv.slice(2));
+const {
+  VERSION: internalRuntimeVersion,
+} = require('../compile/internal-version');
+const path = require('path');
+const Remapping = require('@ampproject/remapping');
+
+/** @type {Remapping.default} */
+const remapping = /** @type {*} */ (Remapping);
+
+/**
+ * @param {!Array<string|object>} sourcemaps
+ * @param {Map<string, string|object>} babelMaps
+ * @param {*} options
+ * @return {string}
+ */
+function massageSourcemaps(sourcemaps, babelMaps, options) {
+  const root = process.cwd();
+  const remapped = remapping(
+    sourcemaps,
+    (f) => {
+      if (f.includes('__SOURCE__')) {
+        return null;
+      }
+      const file = path.join(root, f);
+      // The Babel tranformed file and the original file have the same path,
+      // which makes it difficult to distinguish during remapping's load phase.
+      // We perform some manual path mangling to destingish the babel files
+      // (which have a sourcemap) from the actual source file by pretending the
+      // source file exists in the '__SOURCE__' root directory.
+      const map = babelMaps.get(file);
+      if (!map) {
+        throw new Error(`failed to find sourcemap for babel file "${f}"`);
+      }
+      return {
+        ...map,
+        sourceRoot: path.posix.join('/__SOURCE__/', path.dirname(f)),
+      };
+    },
+    !argv.full_sourcemaps
+  );
+
+  remapped.sources = remapped.sources.map((source) => {
+    if (source?.startsWith('/__SOURCE__/')) {
+      return source.slice('/__SOURCE__/'.length);
+    }
+    return source;
+  });
+  remapped.sourceRoot = getSourceRoot(options);
+  if (remapped.file) {
+    remapped.file = path.basename(remapped.file);
+  }
+
+  return remapped.toString();
+}
+
+/**
+ * Computes the base url for sourcemaps. Custom sourcemap URLs have placeholder
+ * {version} that should be replaced with the actual version. Also, ensures
+ * that a trailing slash exists.
+ * @param {Object} options
+ * @return {string}
+ */
+function getSourceRoot(options) {
+  if (argv.sourcemap_url) {
+    return String(argv.sourcemap_url)
+      .replace(/\{version\}/g, internalRuntimeVersion)
+      .replace(/([^/])$/, '$1/');
+  }
+  if (options.fortesting || !argv._.includes('dist')) {
+    return 'http://localhost:8000/';
+  }
+  return `https://raw.githubusercontent.com/ampproject/amphtml/${internalRuntimeVersion}/`;
+}
+
+module.exports = {
+  massageSourcemaps,
+};