PROTM-1348: Default to no data for branch data mode

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project follows [Semantic Versioning](https://semver.org/spec/v2.0.0.ht
 
 ## [Unreleased]
 
+### Changed
+
+- Cloud branches are now created empty by default: when `branch_data_mode` is omitted from the config, no production data is copied into new branches. This restores the default behavior of `0.0.78` and earlier; only versions `0.0.79` through `0.0.81` copied the last partition of production data into branches by default. Set `branch_data_mode: "last_partition"` in your config to keep copying production data into branches. 
+
 ## [0.0.80] - 2026-06-24
 
 ### Security

README.md

@@ -525,6 +525,7 @@ export default {
 | `token` | `string` | *required* | API token. Supports `${ENV_VAR}` interpolation for environment variables |
 | `baseUrl` | `string` | `"https://api.tinybird.co"` | Tinybird API URL. Use `"https://api.us-east.tinybird.co"` for US region |
 | `devMode` | `"branch"` \| `"local"` | `"branch"` | Development mode. `"branch"` uses Tinybird cloud with branches, `"local"` uses local Docker container |
+| `branch_data_mode` | `"last_partition"` | Data attached to cloud branches on creation. Omit to create empty branches; set `"last_partition"` to copy the last partition of production data |
 
 ### Local Development Mode
 

src/api/branches.test.ts

@@ -223,6 +223,38 @@ describe("Branch API client", () => {
       expect(createParsed.searchParams.get("data")).toBe("last_partition");
     });
 
+    it("omits the data param when no branch_data_mode is given", async () => {
+      const mockBranch = {
+        id: "branch-123",
+        name: "my-feature",
+        token: "p.branch-token",
+        created_at: "2024-01-01T00:00:00Z",
+      };
+
+      mockFetch.mockResolvedValueOnce({
+        ok: true,
+        json: () => Promise.resolve({
+          job: { id: "job-123", status: "waiting" },
+          workspace: { id: "ws-123" },
+        }),
+      });
+      mockFetch.mockResolvedValueOnce({
+        ok: true,
+        json: () => Promise.resolve({ id: "job-123", status: "done" }),
+      });
+      mockFetch.mockResolvedValueOnce({
+        ok: true,
+        json: () => Promise.resolve(mockBranch),
+      });
+
+      await createBranch(config, "my-feature");
+
+      const [createUrl] = mockFetch.mock.calls[0];
+      const createParsed = expectFromParam(createUrl);
+      expect(createParsed.searchParams.get("name")).toBe("my-feature");
+      expect(createParsed.searchParams.get("data")).toBeNull();
+    });
+
     it("uses custom fetch when provided", async () => {
       const customFetch = vi
         .fn()

src/cli/commands/build.ts

@@ -225,10 +225,9 @@ export async function runBuild(options: BuildCommandOptions = {}): Promise<Build
         console.log(`[debug] Getting/creating Tinybird branch: ${config.tinybirdBranch}`);
       }
       try {
-        const branchDataMode: BranchDataMode | undefined =
-          options.lastPartition || config.branchDataMode === "last_partition"
-            ? "last_partition"
-            : undefined;
+        const branchDataMode: BranchDataMode | undefined = options.lastPartition
+          ? "last_partition"
+          : config.branchDataMode ?? undefined;
         const branchOptions = branchDataMode
           ? { branch_data_mode: branchDataMode }
           : undefined;

src/cli/commands/clear.ts

@@ -149,8 +149,8 @@ async function clearCloudBranch(config: ResolvedConfig): Promise<ClearResult> {
 
     // Clear the branch (delete and recreate)
     const branchOptions: CreateBranchOptions | undefined =
-      config.devMode !== "local" && config.branchDataMode === "last_partition"
-        ? { branch_data_mode: "last_partition" }
+      config.devMode !== "local" && config.branchDataMode
+        ? { branch_data_mode: config.branchDataMode }
         : undefined;
 
     const newBranch = await clearBranch(

src/cli/commands/dev.ts

@@ -240,10 +240,9 @@ export async function runDev(
     // Use tinybirdBranch (sanitized name) for Tinybird API, gitBranch for display
     if (config.tinybirdBranch) {
       const branchName = config.tinybirdBranch; // Sanitized name for Tinybird
-      const branchDataMode: BranchDataMode | undefined =
-        options.lastPartition || config.branchDataMode === "last_partition"
-          ? "last_partition"
-          : undefined;
+      const branchDataMode: BranchDataMode | undefined = options.lastPartition
+        ? "last_partition"
+        : config.branchDataMode ?? undefined;
       const branchOptions = branchDataMode
         ? { branch_data_mode: branchDataMode }
         : undefined;

src/cli/commands/preview.test.ts

@@ -120,6 +120,52 @@ describe("Preview command", () => {
       );
     });
 
+    it("creates cloud preview branch without data when branch_data_mode is not set", async () => {
+      const { loadConfigAsync } = await import("../config.js");
+      const { buildFromInclude } = await import("../../generator/index.js");
+      const { getBranch, createBranch } = await import("../../api/branches.js");
+      const { deployToMain } = await import("../../api/deploy.js");
+
+      vi.mocked(loadConfigAsync).mockResolvedValue({
+        include: ["test.ts"],
+        token: "p.test-token",
+        baseUrl: "https://api.tinybird.co",
+        configPath: "/test/tinybird.config.json",
+        devMode: "branch",
+        cwd: "/test",
+        gitBranch: "feature-test",
+        tinybirdBranch: "feature_test",
+        isMainBranch: false,
+        branchDataMode: null,
+      });
+      vi.mocked(buildFromInclude).mockResolvedValue({
+        resources: { datasources: [], pipes: [], connections: [] },
+        entities: { datasources: {}, pipes: {}, connections: {}, rawDatasources: [], rawPipes: [], sourceFiles: [] },
+        stats: { datasourceCount: 0, pipeCount: 0, connectionCount: 0 },
+      });
+      vi.mocked(getBranch).mockRejectedValue(new Error("not found"));
+      vi.mocked(createBranch).mockResolvedValue({
+        id: "b1",
+        name: "tmp_ci_feature_test",
+        token: "p.branch",
+        created_at: "2024-01-01T00:00:00Z",
+      });
+      vi.mocked(deployToMain).mockResolvedValue({
+        success: true,
+        result: "success",
+        datasourceCount: 0,
+        pipeCount: 0,
+        connectionCount: 0,
+      });
+
+      await runPreview();
+      expect(createBranch).toHaveBeenCalledWith(
+        expect.any(Object),
+        "tmp_ci_feature_test",
+        undefined
+      );
+    });
+
     it("ignores config branch_data_mode in local mode", async () => {
       const { loadConfigAsync } = await import("../config.js");
       const { buildFromInclude } = await import("../../generator/index.js");

src/cli/commands/preview.ts

@@ -227,8 +227,8 @@ export async function runPreview(options: PreviewCommandOptions = {}): Promise<P
   try {
     const apiConfig = { baseUrl: config.baseUrl, token: config.token };
     const branchOptions: CreateBranchOptions | undefined =
-      config.branchDataMode === "last_partition"
-        ? { branch_data_mode: "last_partition" }
+      config.branchDataMode
+        ? { branch_data_mode: config.branchDataMode }
         : undefined;
 
     // Check if branch already exists and delete it for a fresh start

src/cli/config-types.ts

@@ -28,6 +28,9 @@ export interface TinybirdConfig {
   baseUrl?: string;
   /** Development mode: "branch" (default) or "local" */
   devMode?: DevMode;
-  /** Branch data mode applied on cloud branch creation (shared snake_case key) */
+  /**
+   * Branch data mode applied on cloud branch creation (shared snake_case key,
+   * also read by the tb CLI). Omit to create branches without data (default).
+   */
   branch_data_mode?: BranchDataMode;
 }

src/cli/config.test.ts

@@ -343,7 +343,23 @@ describe("Config", () => {
       expect(result.branchDataMode).toBe("last_partition");
     });
 
-    it("defaults branch_data_mode to last_partition when missing", () => {
+    it("throws when branch_data_mode is none", () => {
+      const config = {
+        include: ["lib/datasources.ts"],
+        token: "test-token",
+        branch_data_mode: "none",
+      };
+      fs.writeFileSync(
+        path.join(tempDir, "tinybird.json"),
+        JSON.stringify(config)
+      );
+
+      expect(() => loadConfig(tempDir)).toThrow(
+        "Invalid branch_data_mode 'none'. Allowed values are: last_partition."
+      );
+    });
+
+    it("defaults branch_data_mode to no data when missing", () => {
       const config = {
         include: ["lib/datasources.ts"],
         token: "test-token",
@@ -354,10 +370,10 @@ describe("Config", () => {
       );
 
       const result = loadConfig(tempDir);
-      expect(result.branchDataMode).toBe("last_partition");
+      expect(result.branchDataMode).toBeNull();
     });
 
-    it("defaults empty branch_data_mode to last_partition", () => {
+    it("defaults empty branch_data_mode to no data", () => {
       const config = {
         include: ["lib/datasources.ts"],
         token: "test-token",
@@ -369,7 +385,7 @@ describe("Config", () => {
       );
 
       const result = loadConfig(tempDir);
-      expect(result.branchDataMode).toBe("last_partition");
+      expect(result.branchDataMode).toBeNull();
     });
 
     it("throws when branch_data_mode is all_partitions", () => {

src/cli/config.ts

@@ -17,7 +17,6 @@ export {
 import { BRANCH_DATA_MODE_VALUES } from "./config-types.js";
 import type { BranchDataMode, DevMode, TinybirdConfig } from "./config-types.js";
 
-const DEFAULT_BRANCH_DATA_MODE: BranchDataMode = "last_partition";
 
 /**
  * Resolved configuration with all values expanded
@@ -41,7 +40,7 @@ export interface ResolvedConfig {
   isMainBranch: boolean;
   /** Development mode: "branch" or "local" */
   devMode: DevMode;
-  /** Branch data mode configured in tinybird.config.json */
+  /** Branch data mode configured in tinybird.config.json (null = create branches without data, the default) */
   branchDataMode?: BranchDataMode | null;
 }
 
@@ -212,10 +211,10 @@ function resolveBranchDataMode(raw: Record<string, unknown>): { mode: BranchData
   }
 
   const value = raw["branch_data_mode"];
-  if (value === undefined || value === null) return { mode: DEFAULT_BRANCH_DATA_MODE, explicit: false };
+  if (value === undefined || value === null) return { mode: null, explicit: false };
   if (typeof value !== "string") throw new Error("branch_data_mode must be a string.");
   const mode = value.trim().toLowerCase();
-  if (!mode) return { mode: DEFAULT_BRANCH_DATA_MODE, explicit: false };
+  if (!mode) return { mode: null, explicit: false };
   if (!BRANCH_DATA_MODE_VALUES.includes(mode as BranchDataMode)) {
     throw new Error(
       `Invalid branch_data_mode '${value}'. Allowed values are: ${BRANCH_DATA_MODE_VALUES.join(", ")}.`

src/client/base.ts

@@ -342,8 +342,8 @@ export class TinybirdClient {
 
       const branchName = config.tinybirdBranch;
       const branchOptions: CreateBranchOptions | undefined =
-        config.devMode !== "local" && config.branchDataMode === "last_partition"
-          ? { branch_data_mode: "last_partition" }
+        config.devMode !== "local" && config.branchDataMode
+          ? { branch_data_mode: config.branchDataMode }
           : undefined;
 
       // Get or create branch (always fetch fresh to avoid stale cache issues)