From 3661d8380af5035d0c2d0cbce4b89a5de099b902 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Wed, 4 Nov 2020 06:25:37 -1000
Subject: [PATCH] Avoid the same task ending up multiple times in the ssdp
 asyncio.gather (#42815)

---
 homeassistant/components/ssdp/__init__.py | 57 +++++++++++++++--------
 1 file changed, 37 insertions(+), 20 deletions(-)

diff --git a/homeassistant/components/ssdp/__init__.py b/homeassistant/components/ssdp/__init__.py
index 7108034cfb8..b3d8a7f2898 100644
--- a/homeassistant/components/ssdp/__init__.py
+++ b/homeassistant/components/ssdp/__init__.py
@@ -79,7 +79,8 @@ class Scanner:
 
     async def _process_entries(self, entries):
         """Process SSDP entries."""
-        tasks = []
+        entries_to_process = []
+        unseen_locations = set()
 
         for entry in entries:
             key = (entry.st, entry.location)
@@ -89,21 +90,21 @@ class Scanner:
 
             self.seen.add(key)
 
-            tasks.append(self._process_entry(entry))
+            entries_to_process.append(entry)
 
-        if not tasks:
+            if entry.location not in self._description_cache:
+                unseen_locations.add(entry.location)
+
+        if not entries_to_process:
             return
 
-        to_load = [
-            result for result in await asyncio.gather(*tasks) if result is not None
-        ]
-
-        if not to_load:
-            return
+        if unseen_locations:
+            await self._fetch_descriptions(list(unseen_locations))
 
         tasks = []
 
-        for entry, info, domains in to_load:
+        for entry in entries_to_process:
+            info, domains = self._process_entry(entry)
             for domain in domains:
                 _LOGGER.debug("Discovered %s at %s", domain, entry.location)
                 tasks.append(
@@ -112,9 +113,29 @@ class Scanner:
                     )
                 )
 
-        await asyncio.wait(tasks)
+        if tasks:
+            await asyncio.gather(*tasks)
 
-    async def _process_entry(self, entry):
+    async def _fetch_descriptions(self, locations):
+        """Fetch descriptions from locations."""
+
+        for idx, result in enumerate(
+            await asyncio.gather(
+                *[self._fetch_description(location) for location in locations],
+                return_exceptions=True,
+            )
+        ):
+            location = locations[idx]
+
+            if isinstance(result, Exception):
+                _LOGGER.exception(
+                    "Failed to fetch ssdp data from: %s", location, exc_info=result
+                )
+                continue
+
+            self._description_cache[location] = result
+
+    def _process_entry(self, entry):
         """Process a single entry."""
 
         info = {"st": entry.st}
@@ -123,17 +144,13 @@ class Scanner:
                 info[key] = entry.values[key]
 
         if entry.location:
-
             # Multiple entries usually share same location. Make sure
             # we fetch it only once.
             info_req = self._description_cache.get(entry.location)
-
             if info_req is None:
-                info_req = self._description_cache[
-                    entry.location
-                ] = self.hass.async_create_task(self._fetch_description(entry.location))
+                return (None, [])
 
-            info.update(await info_req)
+            info.update(info_req)
 
         domains = set()
         for domain, matchers in self._integration_matchers.items():
@@ -142,9 +159,9 @@ class Scanner:
                     domains.add(domain)
 
         if domains:
-            return (entry, info_from_entry(entry, info), domains)
+            return (info_from_entry(entry, info), domains)
 
-        return None
+        return (None, [])
 
     async def _fetch_description(self, xml_location):
         """Fetch an XML description."""