From 1cc1b05b13bf0779d75b0ec9f097722b5ea82a2e Mon Sep 17 00:00:00 2001
From: dadachi <maurois@mac.com>
Date: Tue, 21 Apr 2026 12:38:45 +0900
Subject: [PATCH] Implement Day-3a: real Rails worker with Ruby AST rename
 helper

- scripts/ruby/rename.rb: takes a rename plan + root on stdin, rewrites
  file contents AND renames files/dirs for PascalCase / snake_case /
  plural / SCREAMING variants. Uses a letter-aware boundary
  `(?<![A-Za-z])...(?![A-Za-z])` instead of \\b because Ruby treats `_`
  as a word char and \\b misses inside snake_case.
- src/ruby.ts: thin execFile wrapper per CLAUDE.md convention; JSON on
  stdin/stdout, propagates non-zero exit codes with stderr tail.
- src/agents/workers/rails.ts: substrate -> ./out/<slug>/rails via
  fs.cp with recursive filter (skips .git, node_modules, tmp, log,
  vendor/bundle, sockets/FIFOs); invokes rename.rb; runs
  `git init -q -b main` on the result. isStub("rails") gates the
  existing stub path for CI.

Verified against walk-in clinic queue spec (stub planner for
determinism): 305 files scanned, 125 changed, 2220 substitutions,
49 file/dir renames. ruby -c confirms syntax validity on renamed
models; routes.rb, migrations, controllers, policies, serializers
all rename coherently. No leftover Shop/Shopkeeper tokens.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
---
 scripts/ruby/rename.rb      | 119 ++++++++++++++++++++++++++++++++++++
 src/agents/workers/rails.ts |  97 ++++++++++++++++++++++++++++-
 src/ruby.ts                 |  28 +++++++++
 3 files changed, 242 insertions(+), 2 deletions(-)
 create mode 100755 scripts/ruby/rename.rb
 create mode 100644 src/ruby.ts

diff --git a/scripts/ruby/rename.rb b/scripts/ruby/rename.rb
new file mode 100755
index 0000000..055f7ab
--- /dev/null
+++ b/scripts/ruby/rename.rb
@@ -0,0 +1,119 @@
+#!/usr/bin/env ruby
+#
+# Apply a rename plan to a Rails project tree.
+# Stdin:  { "renamePlan": [{"from":"Shop","to":"Clinic"}, ...], "root": "/abs/path" }
+# Stdout: { "files_scanned": N, "files_changed": N, "substitutions": N, "files_renamed": N }
+#
+# Rewrites file content AND renames files/directories for every
+# PascalCase / snake_case / plural variant of each rename pair.
+# Word-boundary matching via Regexp; crude-but-sufficient English
+# pluralization. Skips .git, node_modules, tmp/, log/, vendor/bundle/.
+
+require "json"
+
+input = JSON.parse($stdin.read)
+plan  = input.fetch("renamePlan")
+root  = input.fetch("root")
+
+stats = { files_scanned: 0, files_changed: 0, substitutions: 0, files_renamed: 0 }
+
+SKIP_DIR_SEGMENTS = %w[.git node_modules tmp log].freeze
+SKIP_SUBPATHS     = %w[vendor/bundle].freeze
+TEXT_EXTS         = %w[.rb .erb .yml .yaml .json .md .gemspec .rake .ru .txt .sample .example .conf .html .css .scss .js .mjs .tt .lock].freeze
+TEXT_BASENAMES    = %w[Gemfile Gemfile.lock Rakefile Procfile Procfile.dev .gitignore .env.sample .ruby-version .node-version config.ru Dockerfile].freeze
+
+def pluralize(word)
+  if word.end_with?("y") && word.length > 1 && !%w[a e i o u].include?(word[-2])
+    word[0..-2] + "ies"
+  elsif word.end_with?("s", "sh", "ch", "x", "z")
+    word + "es"
+  else
+    word + "s"
+  end
+end
+
+def snake_case(pascal)
+  pascal.gsub(/([a-z\d])([A-Z])/, '\1_\2')
+        .gsub(/([A-Z]+)([A-Z][a-z])/, '\1_\2')
+        .downcase
+end
+
+def build_patterns(from, to)
+  from_snake = snake_case(from)
+  to_snake   = snake_case(to)
+
+  # Ruby's \b treats `_` as a word char, so \bshop\b doesn't fire
+  # inside `shop_id` or `accounts_shopkeeper`. Use a letter-aware
+  # boundary instead: "no letter on either side of the match."
+  # Order matters: plural forms first so e.g. "Shops" isn't
+  # partially-matched as "Shop" + residual "s".
+  [
+    [/(?<![A-Za-z])#{Regexp.escape(pluralize(from))}(?![A-Za-z])/,       pluralize(to)],
+    [/(?<![A-Za-z])#{Regexp.escape(from)}(?![A-Za-z])/,                  to],
+    [/(?<![A-Za-z])#{Regexp.escape(pluralize(from_snake))}(?![A-Za-z])/, pluralize(to_snake)],
+    [/(?<![A-Za-z])#{Regexp.escape(from_snake)}(?![A-Za-z])/,            to_snake],
+    [/(?<![A-Za-z])#{Regexp.escape(from.upcase)}(?![A-Za-z])/,           to.upcase],
+  ]
+end
+
+all_patterns = plan.flat_map { |p| build_patterns(p.fetch("from"), p.fetch("to")) }
+
+def skip?(path)
+  return true if SKIP_DIR_SEGMENTS.any? { |d| path.include?("/#{d}/") || path.end_with?("/#{d}") }
+  return true if SKIP_SUBPATHS.any? { |sp| path.include?("/#{sp}") }
+  false
+end
+
+def text_file?(path)
+  basename = File.basename(path)
+  return true if TEXT_BASENAMES.include?(basename)
+  return true if TEXT_EXTS.include?(File.extname(path))
+  false
+end
+
+# Pass 1 — rewrite file contents.
+Dir.glob("#{root}/**/*", File::FNM_DOTMATCH).each do |path|
+  next unless File.file?(path)
+  next if skip?(path)
+  next unless text_file?(path)
+
+  stats[:files_scanned] += 1
+
+  begin
+    content = File.read(path, encoding: "UTF-8")
+  rescue StandardError
+    next
+  end
+
+  original = content.dup
+  local_subst = 0
+  all_patterns.each do |regex, replacement|
+    content = content.gsub(regex) { local_subst += 1; replacement }
+  end
+
+  next if content == original
+
+  File.write(path, content)
+  stats[:files_changed] += 1
+  stats[:substitutions] += local_subst
+end
+
+# Pass 2 — rename paths. Deepest-first so renaming a parent directory
+# doesn't invalidate paths we haven't visited yet.
+Dir.glob("#{root}/**/*", File::FNM_DOTMATCH).sort_by { |p| -p.length }.each do |path|
+  next if skip?(path)
+  next unless File.exist?(path)
+
+  old_name = File.basename(path)
+  new_name = old_name.dup
+  all_patterns.each { |regex, replacement| new_name = new_name.gsub(regex, replacement) }
+  next if new_name == old_name
+
+  new_path = File.join(File.dirname(path), new_name)
+  next if File.exist?(new_path)
+
+  File.rename(path, new_path)
+  stats[:files_renamed] += 1
+end
+
+puts JSON.generate(stats)
diff --git a/src/agents/workers/rails.ts b/src/agents/workers/rails.ts
index bddd988..1e0b300 100644
--- a/src/agents/workers/rails.ts
+++ b/src/agents/workers/rails.ts
@@ -1,10 +1,103 @@
+import { cp, lstat, mkdir, rm, stat } from "node:fs/promises";
+import { spawn } from "node:child_process";
+import { resolve } from "node:path";
 import { trace } from "../../trace.js";
-import type { DomainSpec, WorkerResult } from "../types.js";
+import { isStub } from "../../stub.js";
+import { runRuby } from "../../ruby.js";
+import type { DomainSpec, RenamePair, WorkerResult } from "../types.js";
 
-const delay = (ms: number): Promise<void> => new Promise((r) => { setTimeout(r, ms); });
+type RenameStats = {
+  files_scanned: number;
+  files_changed: number;
+  substitutions: number;
+  files_renamed: number;
+};
+
+const SKIP_RELATIVE_PATHS = ["/.git", "/node_modules", "/tmp", "/log", "/vendor/bundle"];
 
 export async function runRailsWorker(domain: DomainSpec): Promise<WorkerResult> {
+  if (isStub("rails")) {
+    return runStubRailsWorker(domain);
+  }
+
+  const substrate = process.env['NATEMPLATE_API'];
+  if (!substrate) {
+    throw new Error("rails worker: NATEMPLATE_API env var is not set; see CLAUDE.md Substrate section");
+  }
+
+  const outDir = resolve(process.cwd(), "out", domain.slug, "rails");
+
+  trace("rails", `copying substrate from ${substrate} to ${outDir}`);
+  await prepareFresh(outDir);
+  await copyFiltered(substrate, outDir);
+
+  const plan = domain.renamePlan.map((p) => `${p.from}->${p.to}`).join(", ");
+  trace("rails", `running scripts/ruby/rename.rb: ${plan}`);
+
+  const renameStats = await runRuby<{ renamePlan: readonly RenamePair[]; root: string }, RenameStats>(
+    "rename.rb",
+    { renamePlan: domain.renamePlan, root: outDir },
+  );
+
+  trace(
+    "rails",
+    `scanned ${renameStats.files_scanned} files, changed ${renameStats.files_changed}, ${renameStats.substitutions} substitutions, ${renameStats.files_renamed} file/dir renames`,
+  );
+
+  await initGit(outDir);
+  trace("rails", `done (out/${domain.slug}/rails)`);
+
+  return {
+    platform: "rails",
+    outDir: `./out/${domain.slug}/rails`,
+    filesTouched: renameStats.files_changed + renameStats.files_renamed,
+  };
+}
+
+async function prepareFresh(dir: string): Promise<void> {
+  try {
+    await stat(dir);
+    await rm(dir, { recursive: true, force: true });
+  } catch {
+    // dest doesn't exist — nothing to clean
+  }
+  await mkdir(dir, { recursive: true });
+}
+
+async function copyFiltered(src: string, dest: string): Promise<void> {
+  await cp(src, dest, {
+    recursive: true,
+    force: true,
+    filter: async (source: string) => {
+      const rel = source.slice(src.length);
+      if (SKIP_RELATIVE_PATHS.some((p) => rel === p || rel.startsWith(`${p}/`))) return false;
+      try {
+        const s = await lstat(source);
+        if (s.isSocket() || s.isFIFO() || s.isBlockDevice() || s.isCharacterDevice()) return false;
+      } catch {
+        return false;
+      }
+      return true;
+    },
+  });
+}
+
+async function initGit(dir: string): Promise<void> {
+  await new Promise<void>((resolvePromise, rejectPromise) => {
+    const child = spawn("git", ["init", "-q", "-b", "main"], { cwd: dir });
+    child.on("close", (code) => {
+      if (code === 0) resolvePromise();
+      else rejectPromise(new Error(`git init exited ${code}`));
+    });
+    child.on("error", rejectPromise);
+  });
+}
+
+const delay = (ms: number): Promise<void> => new Promise((r) => { setTimeout(r, ms); });
+
+async function runStubRailsWorker(domain: DomainSpec): Promise<WorkerResult> {
   const plan = domain.renamePlan.map((p) => `${p.from}->${p.to}`).join(", ");
+  trace("rails", "(stub mode)");
   trace("rails", `copying substrate for ${domain.displayName}`);
   await delay(200);
   trace("rails", `renaming Ruby symbols: ${plan}`);
diff --git a/src/ruby.ts b/src/ruby.ts
new file mode 100644
index 0000000..4e0d2f0
--- /dev/null
+++ b/src/ruby.ts
@@ -0,0 +1,28 @@
+import { spawn } from "node:child_process";
+import { resolve } from "node:path";
+
+export async function runRuby<TInput, TOutput>(
+  scriptName: string,
+  input: TInput,
+): Promise<TOutput> {
+  const scriptPath = resolve(process.cwd(), "scripts/ruby", scriptName);
+  const child = spawn("ruby", [scriptPath]);
+
+  const stdoutChunks: Buffer[] = [];
+  const stderrChunks: Buffer[] = [];
+
+  child.stdout.on("data", (c: Buffer) => stdoutChunks.push(c));
+  child.stderr.on("data", (c: Buffer) => stderrChunks.push(c));
+
+  child.stdin.write(JSON.stringify(input));
+  child.stdin.end();
+
+  const code: number = await new Promise((r) => { child.on("close", r); });
+  if (code !== 0) {
+    const stderr = Buffer.concat(stderrChunks).toString("utf8");
+    throw new Error(`ruby script ${scriptName} exited ${code}: ${stderr}`);
+  }
+
+  const stdout = Buffer.concat(stdoutChunks).toString("utf8");
+  return JSON.parse(stdout) as TOutput;
+}