fix(deploy): upload Build Output modules under their manifest paths

.changeset/python-vendored-module-names.md

@@ -0,0 +1,12 @@
+---
+"cf": patch
+---
+
+Fix `cf deploy` for Python Workers with vendored packages
+
+Upload Build Output modules under their manifest paths in `cf deploy`,
+`cf workers versions create` and `cf previews deploy` instead of prefixing them
+with `./`. Python Workers use module names as file paths without normalising
+them, and import vendored packages from the `python_modules/` directory. With
+the prefix, the vendored `workers` SDK was not on the import path, so
+`from workers import ...` failed with `No module named 'workers'` (10021).

AGENTS.md

@@ -415,6 +415,15 @@ derives resource identity from the request URL and sends the request to a
 cf-spawned Miniflare local-explorer instance over shared persisted state. It
 does not read the project's binding declarations.
 
+### Module Workers only
+
+cf supports only ES module Workers. The service-worker format
+(`addEventListener("fetch", …)`, no default export) is deprecated
+(see [Migrate to module Workers](https://developers.cloudflare.com/workers/reference/migrate-to-module-workers/))
+and unsupported. Do not design for it or flag service-worker regressions in
+review; for example, module upload names do not need to match the
+`__<sanitised name>` globals Wrangler's service-worker bundles expect.
+
 ## Generator Conventions
 
 How the generator turns forge methods into yargs commands. Important

packages/cli/src/__tests__/commands/deploy/index.test.ts

@@ -951,12 +951,12 @@ describe("cf deploy", () => {
 
 			expect(exitCode).toBe(0);
 			expect(upload.modules).toContain("index.js");
-			expect(upload.modules).toContain("./lib.cjs");
-			expect(upload.modules).toContain("./data.bin");
-			expect(upload.modules).toContain("./text.txt");
-			expect(upload.modules).toContain("./helper.wasm");
-			expect(upload.modules).toContain("./config.json");
-			expect(upload.modules).toContain("./app.py");
+			expect(upload.modules).toContain("lib.cjs");
+			expect(upload.modules).toContain("data.bin");
+			expect(upload.modules).toContain("text.txt");
+			expect(upload.modules).toContain("helper.wasm");
+			expect(upload.modules).toContain("config.json");
+			expect(upload.modules).toContain("app.py");
 			expect(std.out).toContain("Deployed");
 		});
 	});

packages/cli/src/__tests__/lib/deploy-input.test.ts

@@ -47,7 +47,7 @@ describe("transforms Build Output Specification into deploy input", () => {
 		expect(result.bundleType).toBe("esm");
 		expect(result.content).toBe("export default {}");
 		expect(result.modules).toHaveLength(1);
-		expect(result.modules[0]?.name).toBe("./helper.wasm");
+		expect(result.modules[0]?.name).toBe("helper.wasm");
 		expect(result.modules[0]?.type).toBe("compiled-wasm");
 		expect(Object.keys(result.dependencies)).toHaveLength(2);
 	});
@@ -83,9 +83,9 @@ describe("transforms Build Output Specification into deploy input", () => {
 		expect(builtConfig.manifest?.type).toBe("complete");
 		expect(result.modules).toEqual(
 			expect.arrayContaining([
-				expect.objectContaining({ name: "./chunk.mjs", type: "esm" }),
+				expect.objectContaining({ name: "chunk.mjs", type: "esm" }),
 				expect.objectContaining({
-					name: "./helper.wasm",
+					name: "helper.wasm",
 					type: "compiled-wasm",
 				}),
 			])
@@ -266,11 +266,55 @@ describe("transforms Build Output Specification into deploy input", () => {
 		const typeMap = Object.fromEntries(
 			result.modules.map((m) => [m.name, m.type])
 		);
-		expect(typeMap["./lib.cjs"]).toBe("commonjs");
-		expect(typeMap["./app.py"]).toBe("python");
-		expect(typeMap["./dep.txt"]).toBe("text");
-		expect(typeMap["./blob.bin"]).toBe("buffer");
-		expect(typeMap["./config.json"]).toBe("text");
+		expect(typeMap["lib.cjs"]).toBe("commonjs");
+		expect(typeMap["app.py"]).toBe("python");
+		expect(typeMap["dep.txt"]).toBe("text");
+		expect(typeMap["blob.bin"]).toBe("buffer");
+		expect(typeMap["config.json"]).toBe("text");
+	});
+
+	it("keeps Python vendored module paths exactly as in the manifest", async () => {
+		// Python Workers import vendored packages from `python_modules/` and use
+		// module names as file paths, so a `./` prefix makes `import workers` fail.
+		await seed({
+			".cloudflare/output/v0/config.json": buildOutputRootConfig(),
+			".cloudflare/output/v0/workers/default/worker.config.json": workerConfig({
+				name: "my-worker",
+				compatibilityFlags: ["python_workers"],
+				mainModule: "entry.py",
+				modules: {
+					"entry.py": { type: "python" },
+					"helpers.py": { type: "python" },
+					"python_modules/workers/__init__.py": { type: "data" },
+					"python_modules/_workers_sdk_patch_loader.pth": { type: "data" },
+					"python_modules/workers/workflows.js": { type: "esm" },
+				},
+			}),
+			".cloudflare/output/v0/workers/default/bundle/entry.py":
+				"from workers import WorkerEntrypoint",
+			".cloudflare/output/v0/workers/default/bundle/helpers.py": "pass",
+			".cloudflare/output/v0/workers/default/bundle/python_modules/workers/__init__.py":
+				"",
+			".cloudflare/output/v0/workers/default/bundle/python_modules/_workers_sdk_patch_loader.pth":
+				"",
+			".cloudflare/output/v0/workers/default/bundle/python_modules/workers/workflows.js":
+				"export {}",
+		});
+
+		const {
+			rootConfig,
+			workers: { default: worker },
+		} = await readBuildOutput(process.cwd());
+		const { builtConfig } = parseWorkerConfig(worker, rootConfig);
+		const result = assembleBuildResult(worker, builtConfig);
+
+		expect(result.bundleType).toBe("python");
+		expect(result.modules.map((m) => m.name).sort()).toEqual([
+			"helpers.py",
+			"python_modules/_workers_sdk_patch_loader.pth",
+			"python_modules/workers/__init__.py",
+			"python_modules/workers/workflows.js",
+		]);
 	});
 
 	it("throws when run_worker_first is set without a user Worker", async () => {

packages/cli/src/lib/deploy-input.ts

@@ -274,8 +274,12 @@ export function assembleBuildResult(
 					? readFileSync(filePath)
 					: readFileSync(filePath, "utf8");
 
+			// Use the manifest key unchanged. The runtime normalises `./` in
+			// JavaScript module names, but Python Workers use module names as file
+			// paths without normalising them, so a `./python_modules/...` package
+			// is not on `sys.path`.
 			cfModules.push({
-				name: `./${name}`,
+				name,
 				filePath,
 				content: moduleContent,
 				type: OUTPUT_TO_CF_MODULE_TYPE[meta.type],