From ca6a880c45094619702dd62ade89aca0c647091a Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Wed, 31 Jul 2024 16:51:45 -0500
Subject: [PATCH 1/4] Fix urldispatcher index when variable is preceeded by a
 fixed string after a slash.

---
 aiohttp/web_urldispatcher.py    |  7 +++++--
 tests/test_web_urldispatcher.py | 24 ++++++++++++++++++++++++
 2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/aiohttp/web_urldispatcher.py b/aiohttp/web_urldispatcher.py
index 2ad065d2483..76a05c3334a 100644
--- a/aiohttp/web_urldispatcher.py
+++ b/aiohttp/web_urldispatcher.py
@@ -1108,8 +1108,11 @@ 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
+            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."""
diff --git a/tests/test_web_urldispatcher.py b/tests/test_web_urldispatcher.py
index fe941c8e5e1..f87a4521d7d 100644
--- a/tests/test_web_urldispatcher.py
+++ b/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."""
+    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}"

From 1cb0ea56b92ec2532303b1451ead18f6a697d2e1 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Wed, 31 Jul 2024 17:08:39 -0500
Subject: [PATCH 2/4] Update tests/test_web_urldispatcher.py

---
 tests/test_web_urldispatcher.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/test_web_urldispatcher.py b/tests/test_web_urldispatcher.py
index f87a4521d7d..2a73e750618 100644
--- a/tests/test_web_urldispatcher.py
+++ b/tests/test_web_urldispatcher.py
@@ -919,7 +919,7 @@ async def get(self) -> web.Response:
 
 
 async def test_route_with_regex(aiohttp_client: AiohttpClient) -> None:
-    """Test a route with a regex."""
+    """Test a route with a regex preceded by a fixed string."""
     app = web.Application()
 
     async def handler(request: web.Request) -> web.Response:

From d38b50fa72a3173e57bfe9beed91a55543553b1c Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Wed, 31 Jul 2024 17:14:30 -0500
Subject: [PATCH 3/4] improve comment

---
 aiohttp/web_urldispatcher.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/aiohttp/web_urldispatcher.py b/aiohttp/web_urldispatcher.py
index 76a05c3334a..8a1b93e57d6 100644
--- a/aiohttp/web_urldispatcher.py
+++ b/aiohttp/web_urldispatcher.py
@@ -1111,6 +1111,9 @@ def _get_resource_index_key(self, resource: AbstractResource) -> str:
         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 "/"
 

From 068b976a6b3a06ecf6ebd7d83f4bf97f3fbe8936 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Thu, 1 Aug 2024 10:02:03 -0500
Subject: [PATCH 4/4] changelog

---
 CHANGES/8566.bugfix.rst | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 CHANGES/8566.bugfix.rst

diff --git a/CHANGES/8566.bugfix.rst b/CHANGES/8566.bugfix.rst
new file mode 100644
index 00000000000..61365c0bb61
--- /dev/null
+++ b/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`.