Generate tsconfig once instead of on every webpack invocation

Avoids any potential race condition with parallel webpack invocations

components/common/typescript.gni

@@ -28,6 +28,8 @@ brave_common_web_compile_inputs = [
 
   # webpack config changes warrant a re-build of all webpack builds
   rebase_path("../webpack/webpack.config.js"),
+  rebase_path("../webpack/gen-webpack-grd.js"),
+  rebase_path("../webpack/path-map.js"),
   rebase_path("../webpack/webpack-plugin-depfile.js"),
 
   # typescript config changes warrant a re-build of all typescript builds
@@ -83,6 +85,7 @@ template("transpile_web_ui") {
 
     # make sure rebuilds when common files change
     inputs = brave_common_web_compile_inputs
+    inputs += [ "$root_gen_dir/tsconfig-webpack.json" ]
     if (defined(invoker.inputs)) {
       inputs += invoker.inputs
     }
@@ -90,7 +93,7 @@ template("transpile_web_ui") {
     deps = [
       # Ensure chrome://resources/js file and typescript definitions are
       # generated
-      "//ui/webui/resources:library",
+      "//brave/components/webpack:generate_tsconfig",
     ]
     if (defined(invoker.deps)) {
       deps += invoker.deps

components/webpack/BUILD.gn

@@ -0,0 +1,14 @@
+action("generate_tsconfig") {
+  script = "//brave/script/generate-tsconfig.py"
+  deps = [
+    # Ensure chrome://resources/js file and typescript definitions are
+    # generated
+    "//ui/webui/resources:library",
+  ]
+  inputs = [
+    "gen-tsconfig.js",
+    "path-map.js",
+  ]
+  outputs = [ "$root_gen_dir/tsconfig-webpack.json" ]
+  args = [ "--root_gen_dir=" + rebase_path(root_gen_dir) ]
+}

components/webpack/gen-tsconfig.js

@@ -0,0 +1,56 @@
+const fs = require('fs-extra')
+const path = require('path')
+const pathMap = require('./path-map')
+
+const srcPath = path.resolve(__dirname, '../../../')
+const braveSrcPath = path.join(srcPath, 'brave')
+
+/**
+ * Generates a tsconfig.json file in the gen/ directory
+ * so that typescript can import files from cthe current build's
+ * gen/ directory (e.g. mojom-generated JS).
+ *
+ * @param {*} [atPath=process.env.ROOT_GEN_DIR]
+ * @returns void
+ */
+ async function createGenTsConfig (atPath = process.env.ROOT_GEN_DIR) {
+  const configExtendsFrom = path.relative(
+    atPath,
+    path.join(braveSrcPath, 'tsconfig-webpack.json')
+  )
+  const tsConfigPath = path.join(atPath, 'tsconfig-webpack.json')
+  // Even though ts-loader will get the paths from webpack for module resolution
+  // that does not help some issues where chromium both generates ts definitions
+  // and has JSDoc comments for the .m.js file. Sometimes the JSDoc is incorrect
+  // whilst the associated .d.ts file has the correct definition. Without specifying
+  // the path mapping in the tsconfig.json, Typescript (via ts-loader) will use
+  // the JSDoc, and fail with an error. The example that prompted this is cr.sendWithPromise
+  // where Typescript will not see that the second parameter is an optional spread param
+  // and will fail with an error. Whilst this should be fixed in the chromium source,
+  // it's better to be explicit here so that developers get the same experience at
+  // both compile and design time.
+  const paths = {}
+  for (const path in pathMap) {
+    paths[`${path}/*`] = [`${pathMap[path]}/*`]
+  }
+  const config = {
+    extends: configExtendsFrom,
+    compilerOptions: {
+      paths
+    },
+    references: [
+      {
+        // This ts project is generated by //ui/webui/resources:library
+        path: path.join(atPath, 'ui/webui/resources/tsconfig.json')
+      }
+    ]
+  }
+  await fs.writeFile(tsConfigPath, JSON.stringify(config))
+  return tsConfigPath
+}
+
+createGenTsConfig()
+.catch(err => {
+  console.error(err)
+  process.exit(1)
+})

components/webpack/path-map.js

@@ -0,0 +1,22 @@
+// Copyright (c) 2021 The Brave Authors. All rights reserved.
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// you can obtain one at http://mozilla.org/MPL/2.0/.
+
+const path = require('path')
+
+module.exports = {
+// Find files in the current build configurations /gen directory
+'gen': process.env.ROOT_GEN_DIR,
+// Generated resources at this path are available at chrome://resources and
+// whilst webpack will still bundle, we keep the alias to the served path
+// to minimize knowledge of specific gen/ paths and easily allow us to not bundle
+// them in the future for certain build configurationa, just like chromium.
+'chrome://resources': path.join(process.env.ROOT_GEN_DIR, 'ui/webui/resources/preprocessed'),
+// We import brave-ui direct from source and not from package repo, so we need
+// direct path to the src/ directory.
+'brave-ui': path.resolve(__dirname, '../../node_modules/brave-ui/src'),
+// Force same styled-components module for brave-core and brave-ui
+// which ensure both repos code use the same singletons, e.g. ThemeContext.
+'styled-components': path.resolve(__dirname, '../../node_modules/styled-components'),
+}

components/webpack/webpack.config.js

@@ -4,77 +4,14 @@
 // you can obtain one at http://mozilla.org/MPL/2.0/.
 
 const path = require('path')
-const GenerateDepfilePlugin = require('./webpack-plugin-depfile')
 const fs = require('fs-extra')
 const webpack = require('webpack')
+const GenerateDepfilePlugin = require('./webpack-plugin-depfile')
+const pathMap = require('./path-map')
 
-const srcPath = path.resolve(__dirname, '../../../')
+const tsConfigPath = path.join(process.env.ROOT_GEN_DIR, 'tsconfig-webpack.json')
-const braveSrcPath = path.join(srcPath, 'brave')
-
-const pathMap = {
-  // Find files in the current build configurations /gen directory
-  'gen': process.env.ROOT_GEN_DIR,
-  // Generated resources at this path are available at chrome://resources and
-  // whilst webpack will still bundle, we keep the alias to the served path
-  // to minimize knowledge of specific gen/ paths and easily allow us to not bundle
-  // them in the future for certain build configurationa, just like chromium.
-  'chrome://resources': path.join(process.env.ROOT_GEN_DIR, 'ui/webui/resources/preprocessed'),
-  // We import brave-ui direct from source and not from package repo, so we need
-  // direct path to the src/ directory.
-  'brave-ui': path.resolve(__dirname, '../../node_modules/brave-ui/src'),
-  // Force same styled-components module for brave-core and brave-ui
-  // which ensure both repos code use the same singletons, e.g. ThemeContext.
-  'styled-components': path.resolve(__dirname, '../../node_modules/styled-components'),
-}
-
-/**
- * Generates a tsconfig.json file in the gen/ directoryc
- * so that typescript can import files from cthe current build's
- * gen/ directory (e.g. mojom-generated JS).
- *
- * @param {*} [atPath=process.env.ROOT_GEN_DIR]
- * @returns void
- */
-async function createGenTsConfig (atPath = process.env.ROOT_GEN_DIR) {
-  const configExtendsFrom = path.relative(
-    atPath,
-    path.join(braveSrcPath, 'tsconfig-webpack.json')
-  )
-  const tsConfigPath = path.join(atPath, 'tsconfig.json')
-  // Even though ts-loader will get the paths from webpack for module resolution
-  // that does not help some issues where chromium both generates ts definitions
-  // and has JSDoc comments for the .m.js file. Sometimes the JSDoc is incorrect
-  // whilst the associated .d.ts file has the correct definition. Without specifying
-  // the path mapping in the tsconfig.json, Typescript (via ts-loader) will use
-  // the JSDoc, and fail with an error. The example that prompted this is cr.sendWithPromise
-  // where Typescript will not see that the second parameter is an optional spread param
-  // and will fail with an error. Whilst this should be fixed in the chromium source,
-  // it's better to be explicit here so that developers get the same experience at
-  // both compile and design time.
-  const paths = {}
-  for (const path in pathMap) {
-    paths[`${path}/*`] = [`${pathMap[path]}/*`]
-  }
-  const config = {
-    extends: configExtendsFrom,
-    compilerOptions: {
-      paths
-    },
-    references: [
-      {
-        // This ts project is generated by //ui/webui/resources:library
-        path: path.join(atPath, 'ui/webui/resources/tsconfig.json')
-      }
-    ]
-  }
-  await fs.writeFile(tsConfigPath, JSON.stringify(config))
-  return tsConfigPath
-}
 
 module.exports = async function (env, argv) {
-  // TODO(petemill): only do this once per build, in a separate target
-  // which the webpack targets depend on.
-  const tsConfigPath = await createGenTsConfig()
   // Webpack config object
   return {
     devtool: argv.mode === 'development' ? '#inline-source-map' : false,
@@ -109,9 +46,8 @@ module.exports = async function (env, argv) {
           options: {
             getCustomTransformers: path.join(__dirname, './webpack-ts-transformers.js'),
             allowTsInNodeModules: true,
-            // TODO(petemill): generate in gen/ directory with baseUrl back to src/brave
+            // Use generated tsconfig so that we can point at gen/ output in the
-            // - that would remove any problems with TS analyzing types in an incorrect
+            // correct build configuration output directory.
-            // output directory (e.g. Static/ instead of Component/)
             configFile: tsConfigPath
           }
         },

package.json

@@ -32,6 +32,7 @@
     "pep8": "pycodestyle --max-line-length 120 -r script",
     "pylint": "node ./build/commands/scripts/commands.js pylint",
     "web-ui-gen-grd": "node components/webpack/gen-webpack-grd",
+    "web-ui-gen-tsconfig": "node components/webpack/gen-tsconfig",
     "web-ui": "webpack --config components/webpack/webpack.config.js --colors",
     "build-storybook": "build-storybook -c .storybook -o .storybook-out",
     "storybook": "start-storybook",

script/generate-tsconfig.py

@@ -0,0 +1,43 @@
+import argparse
+import os
+import sys
+from lib.util import execute_stdout, scoped_cwd
+
+
+NPM = 'npm'
+if sys.platform in ['win32', 'cygwin']:
+    NPM += '.cmd'
+
+
+def main():
+    args = parse_args()
+    root_gen_dir = args.root_gen_dir[0]
+    generate_tsconfig(root_gen_dir)
+
+
+def parse_args():
+    parser = argparse.ArgumentParser(description='Generate tsconfig')
+    parser.add_argument('--root_gen_dir', nargs=1)
+    args = parser.parse_args()
+    # validate args
+    if (args.root_gen_dir is None or
+            len(args.root_gen_dir) != 1 or
+            len(args.root_gen_dir[0]) == 0):
+        raise Exception("root_gen_dir argument was not specified correctly")
+    # args are valid
+    return args
+
+def generate_tsconfig(root_gen_dir, env=None):
+    if env is None:
+        env = os.environ.copy()
+
+    args = [NPM, 'run', 'web-ui-gen-tsconfig']
+
+    env["ROOT_GEN_DIR"] = root_gen_dir
+
+    dirname = os.path.abspath(os.path.join(__file__, '..', '..'))
+    with scoped_cwd(dirname):
+        execute_stdout(args, env)
+
+if __name__ == '__main__':
+    sys.exit(main())