Emit deprecation warning

singer_sdk/authenticators.py

@@ -5,6 +5,7 @@
 import base64
 import math
 import typing as t
+import warnings
 from datetime import timedelta
 from types import MappingProxyType
 from urllib.parse import parse_qs, urlencode, urlsplit, urlunsplit
@@ -319,6 +320,13 @@ def __init__(
             password: API password.
         """
         super().__init__(stream=stream)
+        warnings.warn(
+            "BasicAuthenticator is deprecated. Use "
+            "requests.auth.HTTPBasicAuth instead.",
+            DeprecationWarning,
+            stacklevel=2,
+        )
+
         credentials = f"{username}:{password}".encode()
         auth_token = base64.b64encode(credentials).decode("ascii")
         auth_credentials = {"Authorization": f"Basic {auth_token}"}

tests/core/rest/test_authenticators.py

@@ -21,7 +21,11 @@
 )
 from requests.auth import HTTPProxyAuth, _basic_auth_str
 
-from singer_sdk.authenticators import OAuthAuthenticator, OAuthJWTAuthenticator
+from singer_sdk.authenticators import (
+    BasicAuthenticator,
+    OAuthAuthenticator,
+    OAuthJWTAuthenticator,
+)
 
 if t.TYPE_CHECKING:
     import requests_mock
@@ -218,3 +222,13 @@ def test_requests_library_auth(rest_tap: Tap):
 
     assert isinstance(stream.authenticator, HTTPProxyAuth)
     assert r.headers["Proxy-Authorization"] == _basic_auth_str("username", "password")
+
+
+def test_basic_auth_deprecation_warning(rest_tap: Tap):
+    """Validate that a warning is emitted when using BasicAuthenticator."""
+    stream: RESTStream = rest_tap.streams["some_stream"]
+    with pytest.deprecated_call(match="BasicAuthenticator is deprecated") as recorder:
+        BasicAuthenticator(stream=stream, username="username", password="password")  # noqa: S106
+
+    assert len(recorder.list) == 1
+    assert recorder.list[0].filename.endswith("test_authenticators.py")