fix provide_automatic_options override (#5917)

Author: davidism

CHANGES.rst

@@ -23,6 +23,8 @@ Unreleased
     switching ``POST`` to ``GET``. This preserves the current behavior of
     ``GET`` and ``POST`` redirects, and is also correct for frontend libraries
     such as HTMX. :issue:`5895`
+-   ``provide_automatic_options=True`` can be used to enable it for a view when
+    it's disabled in config. Previously, only disabling worked. :issue:`5916`
 
 
 Version 3.1.2

docs/config.rst

@@ -445,7 +445,7 @@ The following configuration values are used internally by Flask:
 .. versionchanged:: 2.3
     ``ENV`` was removed.
 
-.. versionadded:: 3.10
+.. versionadded:: 3.1
     Added :data:`PROVIDE_AUTOMATIC_OPTIONS` to control the default
     addition of autogenerated OPTIONS responses.
 

src/flask/sansio/app.py

@@ -627,19 +627,19 @@ def add_url_rule(
         # Methods that should always be added
         required_methods: set[str] = set(getattr(view_func, "required_methods", ()))
 
-        # starting with Flask 0.8 the view_func object can disable and
-        # force-enable the automatic options handling.
         if provide_automatic_options is None:
             provide_automatic_options = getattr(
                 view_func, "provide_automatic_options", None
             )
 
-        if provide_automatic_options is None:
-            if "OPTIONS" not in methods and self.config["PROVIDE_AUTOMATIC_OPTIONS"]:
-                provide_automatic_options = True
-                required_methods.add("OPTIONS")
-            else:
-                provide_automatic_options = False
+            if provide_automatic_options is None:
+                provide_automatic_options = (
+                    "OPTIONS" not in methods
+                    and self.config["PROVIDE_AUTOMATIC_OPTIONS"]
+                )
+
+        if provide_automatic_options:
+            required_methods.add("OPTIONS")
 
         # Add the required methods now.
         methods |= required_methods

tests/test_basic.py

@@ -20,6 +20,7 @@
 from werkzeug.routing import RequestRedirect
 
 import flask
+from flask.testing import FlaskClient
 
 require_cpython_gc = pytest.mark.skipif(
     python_implementation() != "CPython",
@@ -67,63 +68,61 @@ def test_method_route_no_methods(app):
         app.get("/", methods=["GET", "POST"])
 
 
-def test_provide_automatic_options_attr():
-    app = flask.Flask(__name__)
+def test_provide_automatic_options_attr_disable(
+    app: flask.Flask, client: FlaskClient
+) -> None:
+    """Automatic options can be disabled by the view func attribute."""
 
     def index():
         return "Hello World!"
 
     index.provide_automatic_options = False
-    app.route("/")(index)
-    rv = app.test_client().open("/", method="OPTIONS")
+    app.add_url_rule("/", view_func=index)
+    rv = client.options()
     assert rv.status_code == 405
 
-    app = flask.Flask(__name__)
 
-    def index2():
+def test_provide_automatic_options_attr_enable(
+    app: flask.Flask, client: FlaskClient
+) -> None:
+    """When default automatic options is disabled in config, it can still be
+    enabled by the view function attribute.
+    """
+    app.config["PROVIDE_AUTOMATIC_OPTIONS"] = False
+
+    def index():
         return "Hello World!"
 
-    index2.provide_automatic_options = True
-    app.route("/", methods=["OPTIONS"])(index2)
-    rv = app.test_client().open("/", method="OPTIONS")
-    assert sorted(rv.allow) == ["OPTIONS"]
+    index.provide_automatic_options = True
+    app.add_url_rule("/", view_func=index)
+    rv = client.options()
+    assert rv.allow == {"GET", "HEAD", "OPTIONS"}
 
 
-def test_provide_automatic_options_kwarg(app, client):
-    def index():
-        return flask.request.method
-
-    def more():
-        return flask.request.method
+def test_provide_automatic_options_arg_disable(
+    app: flask.Flask, client: FlaskClient
+) -> None:
+    """Automatic options can be disabled by the route argument."""
 
-    app.add_url_rule("/", view_func=index, provide_automatic_options=False)
-    app.add_url_rule(
-        "/more",
-        view_func=more,
-        methods=["GET", "POST"],
-        provide_automatic_options=False,
-    )
-    assert client.get("/").data == b"GET"
+    @app.get("/", provide_automatic_options=False)
+    def index():
+        return "Hello World!"
 
-    rv = client.post("/")
+    rv = client.options()
     assert rv.status_code == 405
-    assert sorted(rv.allow) == ["GET", "HEAD"]
 
-    rv = client.open("/", method="OPTIONS")
-    assert rv.status_code == 405
 
-    rv = client.head("/")
-    assert rv.status_code == 200
-    assert not rv.data  # head truncates
-    assert client.post("/more").data == b"POST"
-    assert client.get("/more").data == b"GET"
+def test_provide_automatic_options_method_disable(
+    app: flask.Flask, client: FlaskClient
+) -> None:
+    """Automatic options is ignored if the route handles options."""
 
-    rv = client.delete("/more")
-    assert rv.status_code == 405
-    assert sorted(rv.allow) == ["GET", "HEAD", "POST"]
+    @app.route("/", methods=["OPTIONS"])
+    def index():
+        return "", {"X-Test": "test"}
 
-    rv = client.open("/more", method="OPTIONS")
-    assert rv.status_code == 405
+    rv = client.options()
+    assert rv.headers["X-Test"] == "test"
 
 
 def test_request_dispatching(app, client):

tests/test_blueprints.py

@@ -220,28 +220,19 @@ def test_templates_and_static(test_apps):
         assert flask.render_template("nested/nested.txt") == "I'm nested"
 
 
-def test_default_static_max_age(app):
+def test_default_static_max_age(app: flask.Flask) -> None:
     class MyBlueprint(flask.Blueprint):
         def get_send_file_max_age(self, filename):
             return 100
 
-    blueprint = MyBlueprint("blueprint", __name__, static_folder="static")
+    blueprint = MyBlueprint(
+        "blueprint", __name__, url_prefix="/bp", static_folder="static"
+    )
     app.register_blueprint(blueprint)
 
-    # try/finally, in case other tests use this app for Blueprint tests.
-    max_age_default = app.config["SEND_FILE_MAX_AGE_DEFAULT"]
-    try:
-        with app.test_request_context():
-            unexpected_max_age = 3600
-            if app.config["SEND_FILE_MAX_AGE_DEFAULT"] == unexpected_max_age:
-                unexpected_max_age = 7200
-            app.config["SEND_FILE_MAX_AGE_DEFAULT"] = unexpected_max_age
-            rv = blueprint.send_static_file("index.html")
-            cc = parse_cache_control_header(rv.headers["Cache-Control"])
-            assert cc.max_age == 100
-            rv.close()
-    finally:
-        app.config["SEND_FILE_MAX_AGE_DEFAULT"] = max_age_default
+    with app.test_request_context(), blueprint.send_static_file("index.html") as rv:
+        cc = parse_cache_control_header(rv.headers["Cache-Control"])
+        assert cc.max_age == 100
 
 
 def test_templates_list(test_apps):

tests/test_cli.py

@@ -483,12 +483,18 @@ def test_sort(self, app, invoke):
             ["yyy_get_post", "static", "aaa_post"],
             invoke(["routes", "-s", "rule"]).output,
         )
-        match_order = [r.endpoint for r in app.url_map.iter_rules()]
+        match_order = [
+            r.endpoint
+            for r in app.url_map.iter_rules()
+            if r.endpoint != "_automatic_options"
+        ]
         self.expect_order(match_order, invoke(["routes", "-s", "match"]).output)
 
     def test_all_methods(self, invoke):
         output = invoke(["routes"]).output
-        assert "GET, HEAD, OPTIONS, POST" not in output
+        assert "HEAD" not in output
+        assert "OPTIONS" not in output
+
         output = invoke(["routes", "--all-methods"]).output
         assert "GET, HEAD, OPTIONS, POST" in output
 

tests/test_views.py

@@ -2,6 +2,7 @@
 from werkzeug.http import parse_set_header
 
 import flask.views
+from flask.testing import FlaskClient
 
 
 def common_test(app):
@@ -98,44 +99,55 @@ def dispatch_request(self):
     assert rv.data == b"Awesome"
 
 
-def test_view_provide_automatic_options_attr():
-    app = flask.Flask(__name__)
+def test_view_provide_automatic_options_attr_disable(
+    app: flask.Flask, client: FlaskClient
+) -> None:
+    """Automatic options can be disabled by the view class attribute."""
 
-    class Index1(flask.views.View):
+    class Index(flask.views.View):
         provide_automatic_options = False
 
         def dispatch_request(self):
             return "Hello World!"
 
-    app.add_url_rule("/", view_func=Index1.as_view("index"))
-    c = app.test_client()
-    rv = c.open("/", method="OPTIONS")
+    app.add_url_rule("/", view_func=Index.as_view("index"))
+    rv = client.options()
     assert rv.status_code == 405
 
-    app = flask.Flask(__name__)
 
-    class Index2(flask.views.View):
-        methods = ["OPTIONS"]
+def test_view_provide_automatic_options_attr_enable(
+    app: flask.Flask, client: FlaskClient
+) -> None:
+    """When default automatic options is disabled in config, it can still be
+    enabled by the view class attribute.
+    """
+    app.config["PROVIDE_AUTOMATIC_OPTIONS"] = False
+
+    class Index(flask.views.View):
         provide_automatic_options = True
 
         def dispatch_request(self):
             return "Hello World!"
 
-    app.add_url_rule("/", view_func=Index2.as_view("index"))
-    c = app.test_client()
-    rv = c.open("/", method="OPTIONS")
-    assert sorted(rv.allow) == ["OPTIONS"]
+    app.add_url_rule("/", view_func=Index.as_view("index"))
+    rv = client.options("/")
+    assert rv.allow == {"GET", "HEAD", "OPTIONS"}
 
-    app = flask.Flask(__name__)
 
-    class Index3(flask.views.View):
+def test_provide_automatic_options_method_disable(
+    app: flask.Flask, client: FlaskClient
+) -> None:
+    """Automatic options is ignored if the route handles options."""
+
+    class Index(flask.views.View):
+        methods = ["OPTIONS"]
+
         def dispatch_request(self):
-            return "Hello World!"
+            return "", {"X-Test": "test"}
 
-    app.add_url_rule("/", view_func=Index3.as_view("index"))
-    c = app.test_client()
-    rv = c.open("/", method="OPTIONS")
-    assert "OPTIONS" in rv.allow
+    app.add_url_rule("/", view_func=Index.as_view("index"))
+    rv = client.options()
+    assert rv.headers["X-Test"] == "test"
 
 
 def test_implicit_head(app, client):
@@ -180,7 +192,7 @@ def dispatch_request(self):
     app.add_url_rule("/", view_func=Index.as_view("index"))
 
     with pytest.raises(AssertionError):
-        app.add_url_rule("/", view_func=Index.as_view("index"))
+        app.add_url_rule("/other", view_func=Index.as_view("index"))
 
     # But these tests should still pass. We just log a warning.
     common_test(app)