Emit @babel/cli source maps based on configuration files (#14950)

packages/babel-cli/src/babel/dir.ts

@@ -49,16 +49,22 @@ export default async function ({
 
       if (!res) return FILE_TYPE.IGNORED;
 
-      // we've requested explicit sourcemaps to be written to disk
-      if (
-        res.map &&
-        babelOptions.sourceMaps &&
-        babelOptions.sourceMaps !== "inline"
-      ) {
-        const mapLoc = dest + ".map";
-        res.code = util.addSourceMappingUrl(res.code, mapLoc);
-        res.map.file = path.basename(relative);
-        outputFileSync(mapLoc, JSON.stringify(res.map));
+      if (res.map) {
+        let outputMap: "both" | "external" | false = false;
+        if (babelOptions.sourceMaps && babelOptions.sourceMaps !== "inline") {
+          outputMap = "external";
+        } else if (babelOptions.sourceMaps == undefined) {
+          outputMap = util.hasDataSourcemap(res.code) ? "external" : "both";
+        }
+
+        if (outputMap) {
+          const mapLoc = dest + ".map";
+          if (outputMap === "external") {
+            res.code = util.addSourceMappingUrl(res.code, mapLoc);
+          }
+          res.map.file = path.basename(relative);
+          outputFileSync(mapLoc, JSON.stringify(res.map));
+        }
       }
 
       outputFileSync(dest, res.code);

packages/babel-cli/src/babel/file.ts

@@ -12,30 +12,40 @@ import type {
   SectionedSourceMap,
   SourceMapInput,
   TraceMap,
-  DecodedSourceMap,
 } from "@jridgewell/trace-mapping";
+import type { FileResult } from "@babel/core";
 
 type CompilationOutput = {
   code: string;
   map: SourceMapInput;
+  hasRawMap: boolean;
 };
 
 export default async function ({
   cliOptions,
   babelOptions,
 }: CmdOptions): Promise<void> {
-  function buildResult(fileResults: Array<any>): CompilationOutput {
+  function buildResult(fileResults: Array<FileResult>): CompilationOutput {
     const mapSections: SectionedSourceMap["sections"] = [];
 
     let code = "";
     let offset = 0;
 
+    let hasRawMap = false;
+
     for (const result of fileResults) {
       if (!result) continue;
 
+      hasRawMap = !!result.map;
+
       mapSections.push({
         offset: { line: offset, column: 0 },
-        map: result.map || emptyMap(),
+        map: result.map || {
+          version: 3,
+          names: [],
+          sources: [],
+          mappings: [],
+        },
       });
 
       code += result.code + "\n";
@@ -51,7 +61,7 @@ export default async function ({
       sections: mapSections,
     });
     // For some reason, the spec doesn't allow sourceRoot when constructing a
-    // sectioned sorucemap. But AllMap returns a regular sourcemap, we can
+    // sectioned sourcemap. But AllMap returns a regular sourcemap, we can
     // freely add to with a sourceRoot.
     map.sourceRoot = babelOptions.sourceRoot;
 
@@ -67,8 +77,10 @@ export default async function ({
     return {
       map: map,
       code: code,
+      hasRawMap: hasRawMap,
     };
   }
+
   function countNewlines(code: string): number {
     let count = 0;
     let index = -1;
@@ -77,25 +89,25 @@ export default async function ({
     }
     return count;
   }
-  function emptyMap(): DecodedSourceMap {
-    return {
-      version: 3,
-      names: [],
-      sources: [],
-      mappings: [],
-    };
-  }
 
-  function output(fileResults: Array<string>): void {
+  function output(fileResults: Array<FileResult>): void {
     const result = buildResult(fileResults);
 
     if (cliOptions.outFile) {
       fs.mkdirSync(path.dirname(cliOptions.outFile), { recursive: true });
 
-      // we've requested for a sourcemap to be written to disk
+      let outputMap: "both" | "external" | false = false;
       if (babelOptions.sourceMaps && babelOptions.sourceMaps !== "inline") {
+        outputMap = "external";
+      } else if (babelOptions.sourceMaps == undefined && result.hasRawMap) {
+        outputMap = util.hasDataSourcemap(result.code) ? "external" : "both";
+      }
+
+      if (outputMap) {
         const mapLoc = cliOptions.outFile + ".map";
-        result.code = util.addSourceMappingUrl(result.code, mapLoc);
+        if (outputMap === "external") {
+          result.code = util.addSourceMappingUrl(result.code, mapLoc);
+        }
         fs.writeFileSync(
           mapLoc,
           JSON.stringify(encodedMap(result.map as TraceMap)),

packages/babel-cli/src/babel/options.ts

@@ -84,7 +84,12 @@ commander.option(
 );
 
 // General source map formatting.
-commander.option("-s, --source-maps [true|false|inline|both]", "", booleanify);
+commander.option(
+  "-s, --source-maps [true|false|inline|both]",
+  "",
+  booleanify,
+  undefined,
+);
 commander.option(
   "--source-map-target [string]",
   "Set `file` on returned source map.",
@@ -355,6 +360,8 @@ export default function parseArgv(args: Array<string>): CmdOptions | null {
 }
 
 function booleanify(val: any): boolean | any {
+  if (val === undefined) return undefined;
+
   if (val === "true" || val == 1) {
     return true;
   }

packages/babel-cli/src/babel/util.ts

@@ -5,6 +5,8 @@ import fs from "fs";
 
 import * as watcher from "./watcher";
 
+import type { FileResult, InputOptions } from "@babel/core";
+
 export function chmod(src: string, dest: string): void {
   try {
     fs.chmodSync(dest, fs.statSync(src).mode);
@@ -57,40 +59,38 @@ export function addSourceMappingUrl(code: string, loc: string): string {
   return code + "\n//# sourceMappingURL=" + path.basename(loc);
 }
 
+export function hasDataSourcemap(code: string): boolean {
+  const pos = code.lastIndexOf("\n", code.length - 2);
+  return pos != -1 && code.lastIndexOf("//# sourceMappingURL") < pos;
+}
+
 const CALLER = {
   name: "@babel/cli",
 };
 
-export function transformRepl(
-  filename: string,
-  code: string,
-  opts: any,
-): Promise<any> {
+export function transformRepl(filename: string, code: string, opts: any) {
   opts = {
     ...opts,
     caller: CALLER,
     filename,
   };
 
-  return new Promise((resolve, reject) => {
+  return new Promise<FileResult>((resolve, reject) => {
     babel.transform(code, opts, (err, result) => {
       if (err) reject(err);
       else resolve(result);
     });
   });
 }
 
-export async function compile(
-  filename: string,
-  opts: any | Function,
-): Promise<any> {
+export async function compile(filename: string, opts: InputOptions) {
   opts = {
     ...opts,
     caller: CALLER,
   };
 
   // TODO (Babel 8): Use `babel.transformFileAsync`
-  const result: any = await new Promise((resolve, reject) => {
+  const result = await new Promise<FileResult>((resolve, reject) => {
     babel.transformFile(filename, opts, (err, result) => {
       if (err) reject(err);
       else resolve(result);

packages/babel-cli/test/fixtures/babel/dir-sourcemap-config-both/.babelrc

@@ -0,0 +1,3 @@
+{
+  "sourceMaps": "both"
+}

packages/babel-cli/test/fixtures/babel/dir-sourcemap-config-both/dir-sourcemap-config-false/.babelrc

@@ -0,0 +1,3 @@
+{
+  "sourceMaps": false
+}

packages/babel-cli/test/fixtures/babel/dir-sourcemap-config-both/dir-sourcemap-config-false/in-files/src/bar/bar.js

@@ -0,0 +1 @@
+(() => 42)

packages/babel-cli/test/fixtures/babel/dir-sourcemap-config-both/dir-sourcemap-config-false/in-files/src/foo.js

@@ -0,0 +1 @@
+arr.map(x => x * MULTIPLIER);

packages/babel-cli/test/fixtures/babel/dir-sourcemap-config-both/dir-sourcemap-config-false/options.json

@@ -0,0 +1,3 @@
+{
+  "args": ["src", "--out-dir", "lib", "--verbose"]
+}

packages/babel-cli/test/fixtures/babel/dir-sourcemap-config-both/dir-sourcemap-config-false/out-files/lib/bar/bar.js

@@ -0,0 +1,5 @@
+"use strict";
+
+(function () {
+  return 42;
+});

packages/babel-cli/test/fixtures/babel/dir-sourcemap-config-both/dir-sourcemap-config-false/out-files/lib/foo.js

@@ -0,0 +1,5 @@
+"use strict";
+
+arr.map(function (x) {
+  return x * MULTIPLIER;
+});

packages/babel-cli/test/fixtures/babel/dir-sourcemap-config-both/dir-sourcemap-config-false/stdout.txt

@@ -0,0 +1,3 @@
+src/bar/bar.js -> lib/bar/bar.js
+src/foo.js -> lib/foo.js
+Successfully compiled 2 files with Babel (123ms).

packages/babel-cli/test/fixtures/babel/dir-sourcemap-config-both/dir-sourcemap-config-inline/.babelrc

@@ -0,0 +1,3 @@
+{
+  "sourceMaps": "inline"
+}

packages/babel-cli/test/fixtures/babel/dir-sourcemap-config-both/dir-sourcemap-config-inline/in-files/src/bar/bar.js

@@ -0,0 +1 @@
+(() => 42)

packages/babel-cli/test/fixtures/babel/dir-sourcemap-config-both/dir-sourcemap-config-inline/in-files/src/foo.js

@@ -0,0 +1 @@
+arr.map(x => x * MULTIPLIER);

packages/babel-cli/test/fixtures/babel/dir-sourcemap-config-both/dir-sourcemap-config-inline/options.json

@@ -0,0 +1,3 @@
+{
+  "args": ["src", "--out-dir", "lib", "--verbose"]
+}

packages/babel-cli/test/fixtures/babel/dir-sourcemap-config-both/dir-sourcemap-config-inline/stdout.txt

@@ -0,0 +1,3 @@
+src/bar/bar.js -> lib/bar/bar.js
+src/foo.js -> lib/foo.js
+Successfully compiled 2 files with Babel (123ms).

packages/babel-cli/test/fixtures/babel/dir-sourcemap-config-both/dir-sourcemap-config-true/.babelrc

@@ -0,0 +1,3 @@
+{
+  "sourceMaps": true
+}

packages/babel-cli/test/fixtures/babel/dir-sourcemap-config-both/dir-sourcemap-config-true/in-files/src/bar/bar.js

@@ -0,0 +1 @@
+(() => 42)

packages/babel-cli/test/fixtures/babel/dir-sourcemap-config-both/dir-sourcemap-config-true/in-files/src/foo.js

@@ -0,0 +1 @@
+arr.map(x => x * MULTIPLIER);

packages/babel-cli/test/fixtures/babel/dir-sourcemap-config-both/dir-sourcemap-config-true/options.json

@@ -0,0 +1,3 @@
+{
+  "args": ["src", "--out-dir", "lib", "--verbose"]
+}

packages/babel-cli/test/fixtures/babel/dir-sourcemap-config-both/dir-sourcemap-config-true/out-files/lib/bar/bar.js

@@ -0,0 +1,5 @@
+"use strict";
+
+(function () {
+  return 42;
+});

packages/babel-cli/test/fixtures/babel/dir-sourcemap-config-both/dir-sourcemap-config-true/out-files/lib/foo.js

@@ -0,0 +1,5 @@
+"use strict";
+
+arr.map(function (x) {
+  return x * MULTIPLIER;
+});

packages/babel-cli/test/fixtures/babel/dir-sourcemap-config-both/dir-sourcemap-config-true/stdout.txt

@@ -0,0 +1,3 @@
+src/bar/bar.js -> lib/bar/bar.js
+src/foo.js -> lib/foo.js
+Successfully compiled 2 files with Babel (123ms).

packages/babel-cli/test/fixtures/babel/dir-sourcemap-config-both/in-files/src/bar/bar.js

@@ -0,0 +1 @@
+(() => 42)

packages/babel-cli/test/fixtures/babel/dir-sourcemap-config-both/in-files/src/foo.js

@@ -0,0 +1 @@
+arr.map(x => x * MULTIPLIER);

packages/babel-cli/test/fixtures/babel/dir-sourcemap-config-both/options.json

@@ -0,0 +1,3 @@
+{
+  "args": ["src", "--out-dir", "lib", "--verbose"]
+}

packages/babel-cli/test/fixtures/babel/dir-sourcemap-config-both/stdout.txt

@@ -0,0 +1,3 @@
+src/bar/bar.js -> lib/bar/bar.js
+src/foo.js -> lib/foo.js
+Successfully compiled 2 files with Babel (123ms).

packages/babel-cli/test/fixtures/babel/dir-sourcemap-config-false/.babelrc

@@ -0,0 +1,3 @@
+{
+  "sourceMaps": false
+}

packages/babel-cli/test/fixtures/babel/dir-sourcemap-config-false/in-files/src/bar/bar.js

@@ -0,0 +1 @@
+(() => 42)

packages/babel-cli/test/fixtures/babel/dir-sourcemap-config-false/in-files/src/foo.js

@@ -0,0 +1 @@
+arr.map(x => x * MULTIPLIER);

packages/babel-cli/test/fixtures/babel/dir-sourcemap-config-false/options.json

@@ -0,0 +1,3 @@
+{
+  "args": ["src", "--out-dir", "lib", "--verbose"]
+}

packages/babel-cli/test/fixtures/babel/dir-sourcemap-config-false/out-files/lib/bar/bar.js

@@ -0,0 +1,5 @@
+"use strict";
+
+(function () {
+  return 42;
+});

packages/babel-cli/test/fixtures/babel/dir-sourcemap-config-false/out-files/lib/foo.js

@@ -0,0 +1,5 @@
+"use strict";
+
+arr.map(function (x) {
+  return x * MULTIPLIER;
+});

packages/babel-cli/test/fixtures/babel/dir-sourcemap-config-false/stdout.txt

@@ -0,0 +1,3 @@
+src/bar/bar.js -> lib/bar/bar.js
+src/foo.js -> lib/foo.js
+Successfully compiled 2 files with Babel (123ms).

packages/babel-cli/test/fixtures/babel/dir-sourcemap-config-inline-cli-false/.babelrc

@@ -0,0 +1,3 @@
+{
+  "sourceMaps": "both"
+}