Add Linear issue worktree workflow

config/pi/extensions/worktree-agent/worktree.ts

@@ -0,0 +1,93 @@
+import * as fs from "node:fs";
+import * as path from "node:path";
+import type { ExtensionAPI } from "@earendil-works/pi-coding-agent";
+import type { ProgressReporter, WorktreeAgentInput, WorktreeContext } from "./types.ts";
+
+type ExecResult = { stdout: string; stderr: string; code: number | null };
+
+async function git(
+  pi: ExtensionAPI,
+  cwd: string,
+  args: string[],
+  options: { allowFailure?: boolean; timeout?: number } = {},
+): Promise<ExecResult> {
+  const result = await pi.exec("git", ["-C", cwd, ...args], { timeout: options.timeout ?? 30_000 });
+  if (!options.allowFailure && result.code !== 0) {
+    const detail = (result.stderr || result.stdout).trim();
+    throw new Error(`git ${args.join(" ")} failed${detail ? `: ${detail}` : ""}`);
+  }
+  return result;
+}
+
+function slugify(title: string): string {
+  const slug = title
+    .normalize("NFKD")
+    .replace(/[\u0300-\u036f]/g, "")
+    .toLowerCase()
+    .replace(/[^a-z0-9]+/g, "-")
+    .replace(/^-+|-+$/g, "")
+    .slice(0, 48)
+    .replace(/-+$/g, "");
+
+  return slug || "work";
+}
+
+export async function prepareWorktree(
+  pi: ExtensionAPI,
+  cwd: string,
+  input: WorktreeAgentInput,
+  report: ProgressReporter,
+): Promise<WorktreeContext> {
+  if (!/^[A-Za-z][A-Za-z0-9]*-\d+$/.test(input.issueId.trim())) {
+    throw new Error(`Invalid Linear issue identifier: ${input.issueId}`);
+  }
+
+  const repoResult = await git(pi, cwd, ["rev-parse", "--show-toplevel"]);
+  const repoRoot = fs.realpathSync(repoResult.stdout.trim());
+  const statusBefore = await git(pi, repoRoot, ["status", "--porcelain=v1", "--untracked-files=all"]);
+  if (statusBefore.stdout.trim()) {
+    throw new Error("The parent working tree is not clean. Commit, stash, or remove local changes first.");
+  }
+
+  const issueId = input.issueId.trim().toLowerCase();
+  const branchName = `issue/${issueId}-${slugify(input.title)}`;
+  const worktreePath = path.resolve(repoRoot, "..", "worktrees", branchName);
+  const baseRef = input.baseRef?.trim() || "HEAD";
+
+  const branchExists = await git(
+    pi,
+    repoRoot,
+    ["show-ref", "--verify", "--quiet", `refs/heads/${branchName}`],
+    { allowFailure: true },
+  );
+  if (branchExists.code === 0) {
+    throw new Error(`Branch already exists: ${branchName}`);
+  }
+  if (fs.existsSync(worktreePath)) {
+    throw new Error(`Worktree path already exists: ${worktreePath}`);
+  }
+
+  const baseExists = await git(pi, repoRoot, ["rev-parse", "--verify", `${baseRef}^{commit}`], {
+    allowFailure: true,
+  });
+  if (baseExists.code !== 0) {
+    throw new Error(`Base ref does not resolve to a commit: ${baseRef}`);
+  }
+
+  fs.mkdirSync(path.dirname(worktreePath), { recursive: true });
+  report(`Creating ${branchName} at ${worktreePath}`, {
+    phase: "creating-worktree",
+    branchName,
+    worktreePath,
+  });
+  await git(pi, repoRoot, ["worktree", "add", "-b", branchName, worktreePath, baseRef], {
+    timeout: 60_000,
+  });
+
+  return { repoRoot, branchName, worktreePath, baseRef };
+}
+
+export async function isParentClean(pi: ExtensionAPI, repoRoot: string): Promise<boolean> {
+  const status = await git(pi, repoRoot, ["status", "--porcelain=v1", "--untracked-files=all"]);
+  return !status.stdout.trim();
+}