Fix variable shadowing in request_response and websocket_session

fastapi/routing.py

@@ -96,7 +96,7 @@ def request_response(
     async def app(scope: Scope, receive: Receive, send: Send) -> None:
         request = Request(scope, receive, send)
 
-        async def app(scope: Scope, receive: Receive, send: Send) -> None:
+        async def inner_app(scope: Scope, receive: Receive, send: Send) -> None:
             # Starts customization
             response_awaited = False
             async with AsyncExitStack() as request_stack:
@@ -117,7 +117,7 @@ def request_response(
                 )
 
         # Same as in Starlette
-        await wrap_app_handling_exceptions(app, request)(scope, receive, send)
+        await wrap_app_handling_exceptions(inner_app, request)(scope, receive, send)
 
     return app
 
@@ -135,7 +135,7 @@ def websocket_session(
     async def app(scope: Scope, receive: Receive, send: Send) -> None:
         session = WebSocket(scope, receive=receive, send=send)
 
-        async def app(scope: Scope, receive: Receive, send: Send) -> None:
+        async def inner_app(scope: Scope, receive: Receive, send: Send) -> None:
             async with AsyncExitStack() as request_stack:
                 scope["fastapi_inner_astack"] = request_stack
                 async with AsyncExitStack() as function_stack:
@@ -143,7 +143,7 @@ def websocket_session(
                     await func(session)
 
         # Same as in Starlette
-        await wrap_app_handling_exceptions(app, session)(scope, receive, send)
+        await wrap_app_handling_exceptions(inner_app, session)(scope, receive, send)
 
     return app
 

tests/test_variable_shadowing_fix.py

@@ -0,0 +1,93 @@
+"""Simple verification that the routing.py changes are syntactically correct"""
+
+import ast
+import sys
+
+def check_syntax(filepath):
+    """Check if Python file has valid syntax"""
+    try:
+        with open(filepath, 'r', encoding='utf-8') as f:
+            code = f.read()
+        ast.parse(code)
+        return True, "Syntax OK"
+    except SyntaxError as e:
+        return False, f"Syntax Error: {e}"
+
+def check_no_shadowing(filepath):
+    """Check that we fixed the variable shadowing issue"""
+    with open(filepath, 'r', encoding='utf-8') as f:
+        content = f.read()
+    
+    # Check that inner_app exists (our fix)
+    if 'async def inner_app(scope: Scope, receive: Receive, send: Send)' in content:
+        inner_app_count = content.count('async def inner_app(scope: Scope, receive: Receive, send: Send)')
+        if inner_app_count >= 2:  # Should be in both functions
+            return True, f"✓ Found {inner_app_count} instances of 'inner_app' (expected 2)"
+        else:
+            return False, f"✗ Found only {inner_app_count} instances of 'inner_app'"
+    else:
+        return False, "✗ 'inner_app' not found - fix not applied"
+
+def check_wrap_app_handling_exceptions(filepath):
+    """Check that wrap_app_handling_exceptions uses inner_app not app"""
+    with open(filepath, 'r', encoding='utf-8') as f:
+        content = f.read()
+    
+    # Check request_response function
+    lines = content.split('\n')
+    found_request_response = False
+    found_correct_usage = False
+    
+    for i, line in enumerate(lines):
+        if 'def request_response(' in line:
+            found_request_response = True
+        if found_request_response and 'await wrap_app_handling_exceptions(inner_app, request)' in line:
+            found_correct_usage = True
+            break
+    
+    if not found_correct_usage:
+        return False, "✗ wrap_app_handling_exceptions still uses 'app' instead of 'inner_app'"
+    
+    return True, "✓ wrap_app_handling_exceptions correctly uses 'inner_app'"
+
+if __name__ == "__main__":
+    filepath = "fastapi/routing.py"
+    
+    print("=" * 70)
+    print("Verifying Variable Shadowing Fix in routing.py")
+    print("=" * 70)
+    print()
+    
+    # Test 1: Syntax check
+    print("1. Checking Python syntax...")
+    success, message = check_syntax(filepath)
+    print(f"   {message}")
+    if not success:
+        sys.exit(1)
+    
+    # Test 2: Check inner_app exists
+    print("\n2. Checking for 'inner_app' function...")
+    success, message = check_no_shadowing(filepath)
+    print(f"   {message}")
+    if not success:
+        sys.exit(1)
+    
+    # Test 3: Check wrap_app_handling_exceptions usage
+    print("\n3. Checking wrap_app_handling_exceptions usage...")
+    success, message = check_wrap_app_handling_exceptions(filepath)
+    print(f"   {message}")
+    if not success:
+        sys.exit(1)
+    
+    print()
+    print("=" * 70)
+    print("✅ ALL CHECKS PASSED - Variable shadowing fix is correct!")
+    print("=" * 70)
+    print()
+    print("Summary of changes:")
+    print("  • Renamed nested 'app' to 'inner_app' in request_response()")
+    print("  • Renamed nested 'app' to 'inner_app' in websocket_session()")
+    print("  • Updated wrap_app_handling_exceptions calls to use 'inner_app'")
+    print()
+    print("This fix eliminates variable shadowing and improves code clarity")
+    print("without changing any functionality.")