refactor(server): share the no-git-repository checkout-root rewrap (#tech-debt)

apps/server/src/shared/git/git-context.ts

@@ -68,7 +68,8 @@ export async function resolveRepoRoot(
  * Root of the current checkout (`--show-toplevel`) — for a linked worktree
  * this is the worktree path, not the main repository root. No timeout is
  * applied unless one is passed. Throws when `cwd` is not inside a git
- * working tree; callers that need a domain-specific error should rewrap.
+ * working tree; callers that need a domain-specific error should use
+ * resolveCheckoutRootOrThrow.
  */
 export async function resolveCheckoutRoot(
   cwd: string,
@@ -85,6 +86,25 @@ export async function resolveCheckoutRoot(
   );
 }
 
+/**
+ * resolveCheckoutRoot, rewrapping any failure as a 404 of the caller's
+ * domain error class so HTTP/MCP error mapping keys off that class.
+ */
+export async function resolveCheckoutRootOrThrow(
+  cwd: string,
+  commandRunner: CommandRunner,
+  ErrorClass: new (message: string, statusCode: number) => Error
+): Promise<string> {
+  try {
+    return await resolveCheckoutRoot(cwd, commandRunner);
+  } catch {
+    throw new ErrorClass(
+      "No git repository found for the provided working directory.",
+      404
+    );
+  }
+}
+
 export async function resolveWorktreeRoot(
   cwd: string,
   opts: ProbeOptions = {}

apps/server/src/shared/git/worktree.ts

@@ -5,7 +5,7 @@ import { access } from "node:fs/promises";
 import { runCommand, type CommandRunner } from "../lib/run-command.js";
 import {
   normalizePath,
-  resolveCheckoutRoot,
+  resolveCheckoutRootOrThrow,
   resolveCurrentBranch,
 } from "./git-context.js";
 
@@ -115,7 +115,11 @@ export async function createGitWorktree(
     throw new GitWorktreeError("name is required.", 400);
   }
 
-  const repoRoot = await resolveRepoRoot(cwd, commandRunner);
+  const repoRoot = await resolveCheckoutRootOrThrow(
+    cwd,
+    commandRunner,
+    GitWorktreeError
+  );
   const baseBranch = normalizeRefName(input.baseBranch, "main", "baseBranch");
   const createNewBranch = input.createNewBranch ?? false;
   const branchName = createNewBranch
@@ -230,7 +234,11 @@ export async function cleanupGitWorktree(
     throw new GitWorktreeError("cwd is required.", 400);
   }
 
-  const worktreePath = await resolveCurrentCheckoutRoot(cwd, commandRunner);
+  const worktreePath = await resolveCheckoutRootOrThrow(
+    cwd,
+    commandRunner,
+    GitWorktreeError
+  );
   const repoRoot = await resolveCommonRepoRoot(worktreePath, commandRunner);
   const normalizedWorktreePath = normalizePath(worktreePath);
   const normalizedRepoRoot = normalizePath(repoRoot);
@@ -344,27 +352,6 @@ export async function cleanupGitWorktree(
   };
 }
 
-async function resolveRepoRoot(
-  cwd: string,
-  commandRunner: CommandRunner
-): Promise<string> {
-  try {
-    return await resolveCheckoutRoot(cwd, commandRunner);
-  } catch {
-    throw new GitWorktreeError(
-      "No git repository found for the provided working directory.",
-      404
-    );
-  }
-}
-
-async function resolveCurrentCheckoutRoot(
-  cwd: string,
-  commandRunner: CommandRunner
-): Promise<string> {
-  return await resolveRepoRoot(cwd, commandRunner);
-}
-
 async function resolveCommonRepoRoot(
   cwd: string,
   commandRunner: CommandRunner

apps/server/src/shared/github/pr.ts

@@ -1,5 +1,5 @@
 import {
-  resolveCheckoutRoot,
+  resolveCheckoutRootOrThrow,
   resolveCurrentBranch,
 } from "../git/git-context.js";
 import { runCommand, type CommandRunner } from "../lib/run-command.js";
@@ -62,7 +62,11 @@ export async function createPr(
   commandRunner: CommandRunner = runCommand
 ): Promise<CreatePrResult> {
   const cwd = requireString(input.cwd, "cwd");
-  const repoRoot = await resolveRepoRoot(cwd, commandRunner);
+  const repoRoot = await resolveCheckoutRootOrThrow(
+    cwd,
+    commandRunner,
+    GitHubPrError
+  );
   const baseBranch = input.baseBranch?.trim() || "main";
   const branchName = await resolveCurrentBranch(repoRoot, commandRunner);
 
@@ -132,7 +136,11 @@ export async function getPrStatus(
   commandRunner: CommandRunner = runCommand
 ): Promise<GetPrStatusResult> {
   const cwd = requireString(input.cwd, "cwd");
-  const repoRoot = await resolveRepoRoot(cwd, commandRunner);
+  const repoRoot = await resolveCheckoutRootOrThrow(
+    cwd,
+    commandRunner,
+    GitHubPrError
+  );
 
   const args = [
     "pr",
@@ -164,20 +172,6 @@ export async function getPrStatus(
   };
 }
 
-async function resolveRepoRoot(
-  cwd: string,
-  commandRunner: CommandRunner
-): Promise<string> {
-  try {
-    return await resolveCheckoutRoot(cwd, commandRunner);
-  } catch {
-    throw new GitHubPrError(
-      "No git repository found for the provided working directory.",
-      404
-    );
-  }
-}
-
 async function ensureBaseBranchHasDiff(
   repoRoot: string,
   baseBranch: string,

apps/server/test/git-worktree.test.ts

@@ -452,6 +452,28 @@ describe("git worktree services", () => {
     });
   });
 
+  it("rejects with a 404 GitWorktreeError outside a git repository", async () => {
+    const cwd = path.join(tempRoot, "not-a-repo");
+
+    vi.mocked(runCommand).mockImplementation(async (_command, args) => {
+      throw new Error(`fatal: not a git repository: ${args.join(" ")}`);
+    });
+
+    const createPromise = createGitWorktree({ cwd, name: "feature" });
+    await expect(createPromise).rejects.toBeInstanceOf(GitWorktreeError);
+    await expect(createPromise).rejects.toMatchObject({
+      message: "No git repository found for the provided working directory.",
+      statusCode: 404,
+    });
+
+    const cleanupPromise = cleanupGitWorktree({ cwd });
+    await expect(cleanupPromise).rejects.toBeInstanceOf(GitWorktreeError);
+    await expect(cleanupPromise).rejects.toMatchObject({
+      message: "No git repository found for the provided working directory.",
+      statusCode: 404,
+    });
+  });
+
   it("rejects cleanup when called from the primary checkout", async () => {
     const repoRoot = path.join(tempRoot, "repo");
 

apps/server/test/github-pr.test.ts

@@ -163,6 +163,26 @@ describe("github pr services", () => {
     );
   });
 
+  it("rejects with a 404 GitHubPrError outside a git repository", async () => {
+    const runner = vi.fn(async (_command: string, args: string[]) => {
+      throw new Error(`fatal: not a git repository: ${args.join(" ")}`);
+    });
+
+    const createPromise = createPr({ cwd: "/tmp/not-a-repo" }, runner);
+    await expect(createPromise).rejects.toBeInstanceOf(GitHubPrError);
+    await expect(createPromise).rejects.toMatchObject({
+      message: "No git repository found for the provided working directory.",
+      statusCode: 404,
+    });
+
+    const statusPromise = getPrStatus({ cwd: "/tmp/not-a-repo" }, runner);
+    await expect(statusPromise).rejects.toBeInstanceOf(GitHubPrError);
+    await expect(statusPromise).rejects.toMatchObject({
+      message: "No git repository found for the provided working directory.",
+      statusCode: 404,
+    });
+  });
+
   it("reports PR status details", async () => {
     const repoRoot = "/tmp/repo";
     const runner = vi.fn(async (_command: string, args: string[]) => {