fix(app): paginate branch lookup and preserve API error detail

Address CodeRabbit review on #91: resolveReadBranch now pages through all branches (was first page only), includes the API error in the thrown message, and the tests cover the API-failure path (and the shared mock returns pagination).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: kristof-siket

packages/cli/src/lib/app/read-branch.ts

@@ -17,15 +17,31 @@ export async function resolveReadBranch(
   client: ManagementApiClient,
   options: { projectId: string; branchName: string; signal?: AbortSignal },
 ): Promise<ReadBranch | null> {
-  const result = await client.GET("/v1/projects/{projectId}/branches", {
-    params: { path: { projectId: options.projectId }, query: {} },
-    signal: options.signal,
-  });
-  if (result.error || !result.data) {
-    throw new Error(`Failed to list branches for project ${options.projectId}`);
-  }
+  const branches: Array<{
+    id: string;
+    gitName: string;
+    isDefault: boolean;
+    role: BranchKind;
+  }> = [];
+  let cursor: string | undefined;
+
+  do {
+    const result = await client.GET("/v1/projects/{projectId}/branches", {
+      params: { path: { projectId: options.projectId }, query: { cursor } },
+      signal: options.signal,
+    });
+    if (result.error || !result.data) {
+      throw new Error(
+        `Failed to list branches for project ${options.projectId}: ${JSON.stringify(result.error)}`,
+      );
+    }
+
+    branches.push(...result.data.data);
+    cursor = result.data.pagination.hasMore
+      ? (result.data.pagination.nextCursor ?? undefined)
+      : undefined;
+  } while (cursor);
 
-  const branches = result.data.data;
   const chosen =
     branches.find((branch) => branch.gitName === options.branchName) ??
     branches.find((branch) => branch.isDefault) ??

packages/cli/tests/helpers/mock-factories.ts

@@ -55,6 +55,7 @@ export function createProjectClient(
                   options.branchExists === false
                     ? []
                     : [branchRecord(branchName)],
+                pagination: { hasMore: false, nextCursor: null },
               },
             };
           }

packages/cli/tests/read-branch.test.ts

@@ -12,7 +12,12 @@ type RawBranch = {
 
 function clientReturning(branches: RawBranch[]): ManagementApiClient {
   return {
-    GET: vi.fn().mockResolvedValue({ data: { data: branches } }),
+    GET: vi.fn().mockResolvedValue({
+      data: {
+        data: branches,
+        pagination: { hasMore: false, nextCursor: null },
+      },
+    }),
   } as unknown as ManagementApiClient;
 }
 
@@ -68,4 +73,17 @@ describe("resolveReadBranch", () => {
 
     expect(result).toBeNull();
   });
+
+  it("throws when the branches request fails", async () => {
+    const client = {
+      GET: vi.fn().mockResolvedValue({
+        error: { message: "Unauthorized" },
+        response: { status: 401 },
+      }),
+    } as unknown as ManagementApiClient;
+
+    await expect(
+      resolveReadBranch(client, { projectId: "proj_1", branchName: "main" }),
+    ).rejects.toThrow();
+  });
 });