Bug: Bedrock Agent kwargs and null content type, AppSync decorator returns None and context leak, Router duplicates, Function URL base path, Depends() with a class #8584

Expected Behaviour

• Bedrock Agent: only path parameters are injected as kwargs when validation is off, and a Response without content type produces a valid media type key.
• AppSync Events: a decorator with an invalid path still returns the function. AppSync: app.context is cleared after every invocation, including when an exception handler runs.
• Router warns on duplicate routes like the resolver does; LambdaFunctionUrlResolver._get_base_path checks the path; Depends(SomeClass) honours the __init__ signature.

Current Behaviour

1. BedrockAgentResolver(enable_validation=False) passes every event parameter as a kwarg (bedrock_agent.py:350). A query parameter not in the handler signature raises TypeError: unexpected keyword argument. With validation on the middleware rewrites _route_args and masks it.
2. A Response without content type produces "responseBody": {"null": {...}} (bedrock_agent.py:52).
3. @app.on_publish("/default/*/sub") warns "will be skipped" and returns None, so the decorated function disappears (events_appsync/_registry.py:56).
4. AppSyncResolver.resolve() returns the exception handler result before clear_context(), so app.context leaks into the next invocation (appsync.py:160). The docs say context is cleared after each invocation.
5. Router silently overwrites a duplicate route, last wins (api_gateway.py:3185). The resolver warns and keeps the first.
6. LambdaFunctionUrlResolver._get_base_path compares request_context.http.method instead of .path (lambda_function_url.py:57). Unreachable today since Function URLs only use $default, but it is a typo.
7. Depends(SomeClass) uses get_type_hints(cls), which returns class-level annotations, not __init__ parameters (depends.py:121, 201). A class dependency cannot receive Request or a nested Depends: DependencyResolutionError: Svc.__init__() missing 1 required positional argument.

Code snippet

import warnings
from typing import Annotated
from aws_lambda_powertools.event_handler import APIGatewayRestResolver, AppSyncEventsResolver, AppSyncResolver, BedrockAgentResolver, Depends, Request, Response
from aws_lambda_powertools.event_handler.api_gateway import Router
from tests.functional.utils import load_event

ev = load_event("bedrockAgentEventWithPathParams.json")
ev["parameters"].append({"type": "string", "name": "verbose", "value": "true"})
b = BedrockAgentResolver(enable_validation=False)
@b.get("/claims/<claim_id>", description="d")
def g(claim_id: str): return {"claim_id": claim_id}
b.resolve(ev, None)  # TypeError: g() got an unexpected keyword argument 'verbose'

events = AppSyncEventsResolver()
with warnings.catch_warnings():
    warnings.simplefilter("ignore")
    @events.on_publish("/default/*/sub")
    def h4(payload): return payload
print(h4)  # None

gql = AppSyncResolver()
@gql.exception_handler(ValueError)
def eh(e): return {"error": str(e)}
@gql.resolver(type_name="Mutation", field_name="createSomething")
def c(**kw): gql.append_context(x=1); raise ValueError("bad")
gql.resolve(load_event("appSyncDirectResolver.json"), None); print(gql.context)  # {'x': 1}

router = Router()
@router.get("/my/path")
def a(): return {"fn": "a"}
@router.get("/my/path")
def bb(): return {"fn": "b"}
app = APIGatewayRestResolver(); app.include_router(router)  # no warning
print(app.resolve(load_event("apiGatewayProxyEvent.json"), None)["body"])  # {"fn":"b"}

class Svc:
    def __init__(self, request: Request): self.path = request.resolved_event.path
app2 = APIGatewayRestResolver()
@app2.get("/my/path")
def h(svc: Annotated[Svc, Depends(Svc)]): return {"path": svc.path}
app2.resolve(load_event("apiGatewayProxyEvent.json"), None)  # DependencyResolutionError

Possible Solution

Filter Bedrock kwargs to match.groupdict() keys and default the content type to application/json; return func in the AppSync Events registry; wrap AppSync clear_context() in try/finally; warn in Router.route on duplicate keys; use .http.path in Function URL; inspect fn.__init__ when the dependency is a class.

Steps to Reproduce

Run the snippet above with the tests/events fixtures. Full context in #8576.

Powertools for AWS Lambda (Python) version

latest

AWS Lambda function runtime

3.13

Packaging format used

PyPi

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