Fix url dispatcher index when variable is preceded by a fixed string after a slash

CHANGES/8566.bugfix.rst

@@ -0,0 +1 @@
+Fixed url dispatcher index not matching when a variable is preceded by a fixed string after a slash -- by :user:`bdraco`.

aiohttp/web_urldispatcher.py

@@ -1108,8 +1108,14 @@ def register_resource(self, resource: AbstractResource) -> None:
 
  def _get_resource_index_key(self, resource: AbstractResource) -> str:
  """Return a key to index the resource in the resource index."""
- # strip at the first { to allow for variables
- return resource.canonical.partition("{")[0].rstrip("/") or "/"
+ if "{" in (index_key := resource.canonical):
+ # strip at the first { to allow for variables, and than
+ # rpartition at / to allow for variable parts in the path
+ # For example if the canonical path is `/core/locations{tail:.*}`
+ # the index key will be `/core` since index is based on the
+ # url parts split by `/`
+ index_key = index_key.partition("{")[0].rpartition("/")[0]
+ return index_key.rstrip("/") or "/"
 
  def index_resource(self, resource: AbstractResource) -> None:
  """Add a resource to the resource index."""

tests/test_web_urldispatcher.py

@@ -916,3 +916,27 @@ async def get(self) -> web.Response:
  r = await client.get("///a")
  assert r.status == 200
  await r.release()
+
+
+async def test_route_with_regex(aiohttp_client: AiohttpClient) -> None:
+ """Test a route with a regex preceded by a fixed string."""
+ app = web.Application()
+
+ async def handler(request: web.Request) -> web.Response:
+ assert isinstance(request.match_info._route.resource, Resource)
+ return web.Response(text=request.match_info._route.resource.canonical)
+
+ app.router.add_get("/core/locations{tail:.*}", handler)
+ client = await aiohttp_client(app)
+
+ r = await client.get("/core/locations/tail/here")
+ assert r.status == 200
+ assert await r.text() == "/core/locations{tail}"
+
+ r = await client.get("/core/locations_tail_here")
+ assert r.status == 200
+ assert await r.text() == "/core/locations{tail}"
+
+ r = await client.get("/core/locations_tail;id=abcdef")
+ assert r.status == 200
+ assert await r.text() == "/core/locations{tail}"