feat: add e worktree for additional gclient working directories

src/e-worktree.ts

@@ -0,0 +1,194 @@
+#!/usr/bin/env node
+
+import * as childProcess from 'node:child_process';
+import * as fs from 'node:fs';
+import * as os from 'node:os';
+import * as path from 'node:path';
+
+import { program } from 'commander';
+
+import * as evmConfig from './evm-config.js';
+import { color, fatal } from './utils/logging.js';
+import { resolvePath, deleteDir } from './utils/paths.js';
+import * as depot from './utils/depot-tools.js';
+import type { SanitizedConfig } from './types.js';
+
+interface AddOptions {
+  source?: string;
+  out?: string;
+  sync: boolean;
+  force: boolean;
+}
+
+interface CleanOptions {
+  yes: boolean;
+}
+
+function isDerivedWorktree(root: string): boolean {
+  // gclient-new-workdir.py symlinks .gclient to the source checkout; a primary
+  // checkout always has a regular file here, so this alone distinguishes them.
+  const gclient = path.join(root, '.gclient');
+  try {
+    return fs.lstatSync(gclient).isSymbolicLink();
+  } catch {
+    return false;
+  }
+}
+
+program
+  .name('e worktree')
+  .description(
+    'Manage additional gclient working directories that share git objects with an existing checkout',
+  );
+
+program
+  .command('add')
+  .argument('<name>', 'Name for the new build configuration')
+  .argument('<new_workdir>', 'Directory for the new working tree (must not exist)')
+  .description('Create a new worktree and matching build config cloned from an existing one')
+  .option('--source <config>', 'Existing build config to clone from (default: current)')
+  .option(
+    '-o, --out <name>',
+    'Built files will be placed in $root/src/out/$out (default: same as source)',
+  )
+  .option('--no-sync', 'Skip running `e sync` after creating the worktree')
+  .option('-f, --force', 'Overwrite an existing build config of the same name', false)
+  .action((name: string, newWorkdir: string, options: AddOptions) => {
+    try {
+      if (os.platform() === 'win32') {
+        fatal(
+          '`e worktree` is not supported on Windows (gclient-new-workdir.py requires symlinks)',
+        );
+      }
+
+      const sourceName = options.source ?? evmConfig.currentName();
+      const sourceConfig = evmConfig.fetchByName(sourceName);
+      const sourceRoot = sourceConfig.root;
+
+      if (!fs.existsSync(path.join(sourceRoot, '.gclient'))) {
+        fatal(
+          `Source root ${color.path(sourceRoot)} has no .gclient file. ` +
+            `Run ${color.cmd('e sync')} in config ${color.config(sourceName)} first.`,
+        );
+      }
+
+      const targetRoot = resolvePath(newWorkdir);
+      if (fs.existsSync(targetRoot)) {
+        fatal(`Target directory ${color.path(targetRoot)} already exists.`);
+      }
+
+      const filename = evmConfig.pathOf(name);
+      if (!options.force && fs.existsSync(filename)) {
+        fatal(
+          `Build config ${color.config(name)} already exists (${color.path(filename)}). ` +
+            `Use --force to overwrite.`,
+        );
+      }
+
+      depot.ensure();
+
+      console.log(
+        `Creating worktree from ${color.config(sourceName)} (${color.path(sourceRoot)}) ` +
+          `→ ${color.path(targetRoot)}`,
+      );
+      const script = path.join(depot.path, 'gclient-new-workdir.py');
+      depot.spawnSync(
+        sourceConfig,
+        'python3',
+        [script, sourceRoot, targetRoot],
+        { stdio: 'inherit' },
+        'gclient-new-workdir.py failed',
+      );
+
+      const newConfig: SanitizedConfig = structuredClone(sourceConfig);
+      newConfig.root = targetRoot;
+      newConfig.gen.out = options.out ?? sourceConfig.gen.out;
+      newConfig.env.CHROMIUM_BUILDTOOLS_PATH = path.join(targetRoot, 'src', 'buildtools');
+
+      evmConfig.save(name, newConfig);
+      console.log(`New build config ${color.config(name)} created in ${color.path(filename)}`);
+
+      evmConfig.setCurrent(name);
+      console.log(`Now using config ${color.config(name)}`);
+
+      if (options.sync) {
+        console.log(
+          `Running ${color.cmd('e sync')} to fetch toolchains and apply patches in the new worktree...`,
+        );
+        const e = path.resolve(import.meta.dirname, 'e');
+        const opts: childProcess.ExecFileSyncOptions = { stdio: 'inherit' };
+        childProcess.execFileSync(process.execPath, [e, 'sync'], opts);
+      } else {
+        console.log(
+          `${color.info} Skipped sync. Run ${color.cmd('e sync')} in this config before building.`,
+        );
+      }
+
+      console.log(`${color.success} Worktree ready at ${color.path(targetRoot)}`);
+      console.log(
+        `${color.info} When finished, remove with ${color.cmd(`e worktree clean ${name} --yes`)}`,
+      );
+    } catch (e) {
+      fatal(e);
+    }
+  });
+
+program
+  .command('clean')
+  .argument('<name>', 'Build config whose worktree should be deleted')
+  .description('Delete a worktree directory and its build config')
+  .option('--yes', 'Confirm deletion (required; this removes the entire worktree directory)', false)
+  .action((name: string, options: CleanOptions) => {
+    try {
+      const config = evmConfig.fetchByName(name);
+      const root = config.root;
+
+      if (!isDerivedWorktree(root)) {
+        fatal(
+          `${color.path(root)} does not look like a worktree created by ${color.cmd('e worktree add')} ` +
+            `(.gclient must be a symlink). Refusing to delete.`,
+        );
+      }
+
+      let active: string | null;
+      try {
+        active = evmConfig.currentName();
+      } catch {
+        active = null;
+      }
+      if (active === name) {
+        fatal(
+          `Config ${color.config(name)} is currently in use. ` +
+            `Switch to another config with ${color.cmd('e use <other>')} first.`,
+        );
+      }
+
+      if (!options.yes) {
+        fatal(
+          `This will delete ${color.path(root)} and the ${color.config(name)} config. ` +
+            `Re-run with ${color.cmd('--yes')} to confirm.`,
+        );
+      }
+
+      console.log(`Deleting ${color.path(root)}...`);
+      deleteDir(root);
+
+      evmConfig.remove(name);
+      console.log(`Removed config ${color.config(name)}`);
+
+      console.log(`${color.success} Worktree ${color.path(root)} removed`);
+    } catch (e) {
+      fatal(e);
+    }
+  });
+
+program.addHelpText(
+  'after',
+  `
+Examples:
+  $ e worktree add testing2 ~/src/electron2
+  $ e worktree add asan ~/src/electron-asan --source testing -o Asan --no-sync
+  $ e worktree clean testing2 --yes`,
+);
+
+program.parse(process.argv);

src/e.ts

@@ -83,6 +83,10 @@ program.description('Electron build tool').usage('<command> [commandArgs...]');
 program
   .command('init [options] <name>', 'Create a new build config')
   .alias('new')
+  .command(
+    'worktree <subcommand>',
+    'Manage gclient working directories that share git objects with an existing checkout',
+  )
   .command('sync [gclientArgs...]', 'Get or update source code')
   .command('build [options]', 'Build Electron and other things')
   .alias('make')