From 94204242a737368926e0e48342ffe025dc7b3409 Mon Sep 17 00:00:00 2001
From: "Daniel J. Beutel" <daniel@flower.ai>
Date: Mon, 1 Apr 2024 19:42:54 +0200
Subject: [PATCH] Remove experimental / add preview feature warnings (#3187)

---
 src/py/flwr/client/app.py                         | 4 +---
 src/py/flwr/client/client_app.py                  | 7 +++++++
 src/py/flwr/client/grpc_rere_client/connection.py | 4 +---
 src/py/flwr/common/logger.py                      | 8 ++++----
 src/py/flwr/server/server_app.py                  | 3 +++
 5 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/src/py/flwr/client/app.py b/src/py/flwr/client/app.py
index 644d37060d53..7104ba267f57 100644
--- a/src/py/flwr/client/app.py
+++ b/src/py/flwr/client/app.py
@@ -36,7 +36,7 @@
     TRANSPORT_TYPES,
 )
 from flwr.common.exit_handlers import register_exit_handlers
-from flwr.common.logger import log, warn_deprecated_feature, warn_experimental_feature
+from flwr.common.logger import log, warn_deprecated_feature
 from flwr.common.message import Error
 from flwr.common.object_ref import load_app, validate
 from flwr.common.retry_invoker import RetryInvoker, exponential
@@ -385,8 +385,6 @@ def _load_client_app() -> ClientApp:
             return ClientApp(client_fn=client_fn)
 
         load_client_app_fn = _load_client_app
-    else:
-        warn_experimental_feature("`load_client_app_fn`")
 
     # At this point, only `load_client_app_fn` should be used
     # Both `client` and `client_fn` must not be used directly
diff --git a/src/py/flwr/client/client_app.py b/src/py/flwr/client/client_app.py
index 0b56219807c6..79e7720cbb8e 100644
--- a/src/py/flwr/client/client_app.py
+++ b/src/py/flwr/client/client_app.py
@@ -23,6 +23,7 @@
 from flwr.client.mod.utils import make_ffn
 from flwr.client.typing import ClientFn, Mod
 from flwr.common import Context, Message, MessageType
+from flwr.common.logger import warn_preview_feature
 
 from .typing import ClientAppCallable
 
@@ -123,6 +124,8 @@ def train_decorator(train_fn: ClientAppCallable) -> ClientAppCallable:
             if self._call:
                 raise _registration_error(MessageType.TRAIN)
 
+            warn_preview_feature("ClientApp-register-train-function")
+
             # Register provided function with the ClientApp object
             # Wrap mods around the wrapped step function
             self._train = make_ffn(train_fn, self._mods)
@@ -151,6 +154,8 @@ def evaluate_decorator(evaluate_fn: ClientAppCallable) -> ClientAppCallable:
             if self._call:
                 raise _registration_error(MessageType.EVALUATE)
 
+            warn_preview_feature("ClientApp-register-evaluate-function")
+
             # Register provided function with the ClientApp object
             # Wrap mods around the wrapped step function
             self._evaluate = make_ffn(evaluate_fn, self._mods)
@@ -179,6 +184,8 @@ def query_decorator(query_fn: ClientAppCallable) -> ClientAppCallable:
             if self._call:
                 raise _registration_error(MessageType.QUERY)
 
+            warn_preview_feature("ClientApp-register-query-function")
+
             # Register provided function with the ClientApp object
             # Wrap mods around the wrapped step function
             self._query = make_ffn(query_fn, self._mods)
diff --git a/src/py/flwr/client/grpc_rere_client/connection.py b/src/py/flwr/client/grpc_rere_client/connection.py
index 06573ffaafb7..ba8b0d022685 100644
--- a/src/py/flwr/client/grpc_rere_client/connection.py
+++ b/src/py/flwr/client/grpc_rere_client/connection.py
@@ -34,7 +34,7 @@
     PING_RANDOM_RANGE,
 )
 from flwr.common.grpc import create_channel
-from flwr.common.logger import log, warn_experimental_feature
+from flwr.common.logger import log
 from flwr.common.message import Message, Metadata
 from flwr.common.retry_invoker import RetryInvoker
 from flwr.common.serde import message_from_taskins, message_to_taskres
@@ -103,8 +103,6 @@ def grpc_request_response(  # pylint: disable=R0914, R0915
     create_node : Optional[Callable]
     delete_node : Optional[Callable]
     """
-    warn_experimental_feature("`grpc-rere`")
-
     if isinstance(root_certificates, str):
         root_certificates = Path(root_certificates).read_bytes()
 
diff --git a/src/py/flwr/common/logger.py b/src/py/flwr/common/logger.py
index 2bc41773ed61..258809ce062f 100644
--- a/src/py/flwr/common/logger.py
+++ b/src/py/flwr/common/logger.py
@@ -164,13 +164,13 @@ def configure(
 log = logger.log  # pylint: disable=invalid-name
 
 
-def warn_experimental_feature(name: str) -> None:
-    """Warn the user when they use an experimental feature."""
+def warn_preview_feature(name: str) -> None:
+    """Warn the user when they use a preview feature."""
     log(
         WARN,
-        """EXPERIMENTAL FEATURE: %s
+        """PREVIEW FEATURE: %s
 
-            This is an experimental feature. It could change significantly or be removed
+            This is a preview feature. It could change significantly or be removed
             entirely in future versions of Flower.
         """,
         name,
diff --git a/src/py/flwr/server/server_app.py b/src/py/flwr/server/server_app.py
index 1b2eab87fdaa..ea2eb3fd1a69 100644
--- a/src/py/flwr/server/server_app.py
+++ b/src/py/flwr/server/server_app.py
@@ -18,6 +18,7 @@
 from typing import Callable, Optional
 
 from flwr.common import Context, RecordSet
+from flwr.common.logger import warn_preview_feature
 from flwr.server.strategy import Strategy
 
 from .client_manager import ClientManager
@@ -120,6 +121,8 @@ def main_decorator(main_fn: ServerAppCallable) -> ServerAppCallable:
                     """,
                 )
 
+            warn_preview_feature("ServerApp-register-main-function")
+
             # Register provided function with the ServerApp object
             self._main = main_fn