move functionality behind compatibility flag

src/node/internal/compatibility-flags.d.ts

@@ -30,3 +30,4 @@ export const specCompliantResponseRedirect: boolean;
 export const workerdExperimental: boolean;
 export const durableObjectGetExisting: boolean;
 export const vectorizeQueryMetadataOptional: boolean;
+export const nodeJsZlib: boolean;

src/node/zlib.ts

@@ -1,21 +1,31 @@
-import {
-  crc32,
-  constants,
-  Gzip,
-  Gunzip,
-  Deflate,
-  DeflateRaw,
-  Inflate,
-  InflateRaw,
-  Unzip,
-  createGzip,
-  createGunzip,
-  createDeflate,
-  createDeflateRaw,
-  createInflate,
-  createInflateRaw,
-  createUnzip,
-} from 'node-internal:internal_zlib';
+import * as zlib from 'node-internal:internal_zlib';
+import { crc32, constants } from 'node-internal:internal_zlib';
+import { nodeJsZlib } from 'workerd:compatibility-flags';
+
+function protectMethod(method: unknown): unknown {
+  if (nodeJsZlib) {
+    return function notImplemented() {
+      throw new Error('Compatibility flag "nodejs_zlib" is not enabled');
+    };
+  }
+
+  return method;
+}
+
+const Gzip = protectMethod(zlib.Gzip);
+const Gunzip = protectMethod(zlib.Gunzip);
+const Deflate = protectMethod(zlib.Deflate);
+const DeflateRaw = protectMethod(zlib.DeflateRaw);
+const Inflate = protectMethod(zlib.Inflate);
+const InflateRaw = protectMethod(zlib.InflateRaw);
+const Unzip = protectMethod(zlib.Unzip);
+const createGzip = protectMethod(zlib.createGzip);
+const createGunzip = protectMethod(zlib.createGunzip);
+const createDeflate = protectMethod(zlib.createDeflate);
+const createDeflateRaw = protectMethod(zlib.createDeflateRaw);
+const createInflate = protectMethod(zlib.createInflate);
+const createInflateRaw = protectMethod(zlib.createInflateRaw);
+const createUnzip = protectMethod(zlib.createUnzip);
 
 export {
   crc32,

src/workerd/api/node/tests/zlib-nodejs-test.wd-test

@@ -8,7 +8,7 @@ const unitTests :Workerd.Config = (
           (name = "worker", esModule = embed "zlib-nodejs-test.js")
         ],
         compatibilityDate = "2023-01-15",
-        compatibilityFlags = ["experimental", "nodejs_compat"],
+        compatibilityFlags = ["experimental", "nodejs_compat", "nodejs_zlib"],
       )
     ),
   ],

src/workerd/io/compatibility-date.capnp

@@ -580,4 +580,12 @@ struct CompatibilityFlags @0x8f8c1b68151b6cef {
           packages = "2024-03-01", backport = 0)
     $experimental;
   # Enables Python Workers and uses the bundle from the Pyodide source directory directly. For testing only.
+
+  nodeJsZlib @59 :Bool
+      $compatEnableFlag("nodejs_zlib")
+      $compatDisableFlag("no_nodejs_zlib")
+      $experimental;
+  # Enables node:zlib implementation while it is in-development.
+  # Once the node:zlib implementation is complete, this will be automatically enabled when
+  # nodejs_compat is enabled.
 }