Fix type hinting for load_env (#2107)

* Deprecate `load_env` in favor of `env_prefix`

`load_env` both enabled/disabled environment variable parsing, while
also letting the user modify the env prefix. Deprecate the ability to
disable environment parsing, and add a new config variable to track the
user's desired prefix for environment-based configuration.

Resolves: #2102

* Add a few common .gitignore patterns

tests/test_config.py

@@ -59,14 +59,14 @@ def test_load_from_object_string_exception(app):
         app.config.load("test_config.Config.test")
 
 
-def test_auto_load_env():
+def test_auto_env_prefix():
     environ["SANIC_TEST_ANSWER"] = "42"
     app = Sanic(name=__name__)
     assert app.config.TEST_ANSWER == 42
     del environ["SANIC_TEST_ANSWER"]
 
 
-def test_auto_load_bool_env():
+def test_auto_bool_env_prefix():
     environ["SANIC_TEST_ANSWER"] = "True"
     app = Sanic(name=__name__)
     assert app.config.TEST_ANSWER is True
@@ -80,6 +80,12 @@ def test_dont_load_env():
     del environ["SANIC_TEST_ANSWER"]
 
 
+@pytest.mark.parametrize('load_env', [None, False, "", "MYAPP_"])
+def test_load_env_deprecation(load_env):
+    with pytest.warns(DeprecationWarning, match=r"21\.12"):
+        _ = Sanic(name=__name__, load_env=load_env)
+
+
 def test_load_env_prefix():
     environ["MYAPP_TEST_ANSWER"] = "42"
     app = Sanic(name=__name__, load_env="MYAPP_")
@@ -87,6 +93,14 @@ def test_load_env_prefix():
     del environ["MYAPP_TEST_ANSWER"]
 
 
+@pytest.mark.parametrize('env_prefix', [None, ""])
+def test_empty_load_env_prefix(env_prefix):
+    environ["SANIC_TEST_ANSWER"] = "42"
+    app = Sanic(name=__name__, env_prefix=env_prefix)
+    assert getattr(app.config, "TEST_ANSWER", None) is None
+    del environ["SANIC_TEST_ANSWER"]
+
+
 def test_load_env_prefix_float_values():
     environ["MYAPP_TEST_ROI"] = "2.3"
     app = Sanic(name=__name__, load_env="MYAPP_")
@@ -101,6 +115,27 @@ def test_load_env_prefix_string_value():
     del environ["MYAPP_TEST_TOKEN"]
 
 
+def test_env_prefix():
+    environ["MYAPP_TEST_ANSWER"] = "42"
+    app = Sanic(name=__name__, env_prefix="MYAPP_")
+    assert app.config.TEST_ANSWER == 42
+    del environ["MYAPP_TEST_ANSWER"]
+
+
+def test_env_prefix_float_values():
+    environ["MYAPP_TEST_ROI"] = "2.3"
+    app = Sanic(name=__name__, env_prefix="MYAPP_")
+    assert app.config.TEST_ROI == 2.3
+    del environ["MYAPP_TEST_ROI"]
+
+
+def test_env_prefix_string_value():
+    environ["MYAPP_TEST_TOKEN"] = "somerandomtesttoken"
+    app = Sanic(name=__name__, env_prefix="MYAPP_")
+    assert app.config.TEST_TOKEN == "somerandomtesttoken"
+    del environ["MYAPP_TEST_TOKEN"]
+
+
 def test_load_from_file(app):
     config = dedent(
         """

tests/test_keep_alive_timeout.py

@@ -1,4 +1,5 @@
 import asyncio
+import platform
 
 from asyncio import sleep as aio_sleep
 from json import JSONDecodeError
@@ -6,7 +7,6 @@ from os import environ
 
 import httpcore
 import httpx
-import platform
 import pytest
 
 from sanic_testing.testing import HOST, SanicTestClient