🐛 Fix edge case with repeated aliases names not shown in OpenAPI (#2351)

Co-authored-by: Sebastián Ramírez <tiangolo@gmail.com>

fastapi/openapi/utils.py

@@ -223,7 +223,9 @@ def get_openapi_path(
             parameters.extend(operation_parameters)
             if parameters:
                 operation["parameters"] = list(
-                    {param["name"]: param for param in parameters}.values()
+                    {
+                        (param["in"], param["name"]): param for param in parameters
+                    }.values()
                 )
             if method in METHODS_WITH_BODY:
                 request_body_oai = get_openapi_operation_request_body(

tests/test_repeated_parameter_alias.py

@@ -0,0 +1,100 @@
+from fastapi import FastAPI, Path, Query, status
+from fastapi.testclient import TestClient
+
+app = FastAPI()
+
+
+@app.get("/{repeated_alias}")
+def get_parameters_with_repeated_aliases(
+    path: str = Path(..., alias="repeated_alias"),
+    query: str = Query(..., alias="repeated_alias"),
+):
+    return {"path": path, "query": query}
+
+
+client = TestClient(app)
+
+openapi_schema = {
+    "components": {
+        "schemas": {
+            "HTTPValidationError": {
+                "properties": {
+                    "detail": {
+                        "items": {"$ref": "#/components/schemas/ValidationError"},
+                        "title": "Detail",
+                        "type": "array",
+                    }
+                },
+                "title": "HTTPValidationError",
+                "type": "object",
+            },
+            "ValidationError": {
+                "properties": {
+                    "loc": {
+                        "items": {"anyOf": [{"type": "string"}, {"type": "integer"}]},
+                        "title": "Location",
+                        "type": "array",
+                    },
+                    "msg": {"title": "Message", "type": "string"},
+                    "type": {"title": "Error Type", "type": "string"},
+                },
+                "required": ["loc", "msg", "type"],
+                "title": "ValidationError",
+                "type": "object",
+            },
+        }
+    },
+    "info": {"title": "FastAPI", "version": "0.1.0"},
+    "openapi": "3.0.2",
+    "paths": {
+        "/{repeated_alias}": {
+            "get": {
+                "operationId": "get_parameters_with_repeated_aliases__repeated_alias__get",
+                "parameters": [
+                    {
+                        "in": "path",
+                        "name": "repeated_alias",
+                        "required": True,
+                        "schema": {"title": "Repeated Alias", "type": "string"},
+                    },
+                    {
+                        "in": "query",
+                        "name": "repeated_alias",
+                        "required": True,
+                        "schema": {"title": "Repeated Alias", "type": "string"},
+                    },
+                ],
+                "responses": {
+                    "200": {
+                        "content": {"application/json": {"schema": {}}},
+                        "description": "Successful Response",
+                    },
+                    "422": {
+                        "content": {
+                            "application/json": {
+                                "schema": {
+                                    "$ref": "#/components/schemas/HTTPValidationError"
+                                }
+                            }
+                        },
+                        "description": "Validation Error",
+                    },
+                },
+                "summary": "Get Parameters With Repeated Aliases",
+            }
+        }
+    },
+}
+
+
+def test_openapi_schema():
+    response = client.get("/openapi.json")
+    assert response.status_code == status.HTTP_200_OK
+    actual_schema = response.json()
+    assert actual_schema == openapi_schema
+
+
+def test_get_parameters():
+    response = client.get("/test_path", params={"repeated_alias": "test_query"})
+    assert response.status_code == 200, response.text
+    assert response.json() == {"path": "test_path", "query": "test_query"}