Don't spam logs about deleted users

User.get_or_fetch_by_(apid|nickname) are the only external users of fetch_and_prepare_user_from_ap_id,
thus there’s no point in duplicating logging, expecially not at error level.
Currently (duplicated) _not_found errors for users make up the bulk of my logs
and are created almost every second. Deleted users are a common occurence and not
worth logging outside of debug

lib/pleroma/user.ex

@@ -2003,8 +2003,16 @@ def get_or_fetch_by_ap_id(ap_id, options \\ []) do
         Logger.debug("Rejected to fetch user due to MRF: #{ap_id}")
         {:error, {:reject, :mrf}}
 
-      e ->
+      {_, {:error, :not_found}} ->
+        Logger.debug("User doesn't exist (anymore): #{ap_id}")
+        {:error, :not_found}
+
+      {_, {:error, e}} ->
         Logger.error("Could not fetch user #{ap_id}, #{inspect(e)}")
+        {:error, e}
+
+      e ->
+        Logger.error("Unexpected error condition while fetching user #{ap_id}, #{inspect(e)}")
         {:error, :not_found}
     end
   end

lib/pleroma/web/activity_pub/activity_pub.ex

@@ -1750,19 +1750,16 @@ defp fetch_and_prepare_user_from_ap_id(ap_id, additional) do
     else
       # If this has been deleted, only log a debug and not an error
       {:error, {"Object has been deleted", _, _} = e} ->
-        Logger.debug("Could not decode user at fetch #{ap_id}, #{inspect(e)}")
-        {:error, e}
+        Logger.debug("User was explicitly deleted #{ap_id}, #{inspect(e)}")
+        {:error, :not_found}
 
-      {:reject, reason} = e ->
-        Logger.debug("Rejected user #{ap_id}: #{inspect(reason)}")
+      {:reject, _reason} = e ->
         {:error, e}
 
       {:valid, reason} ->
-        Logger.debug("Data is not a valid user #{ap_id}: #{inspect(reason)}")
-        {:error, "Not a user"}
+        {:error, {:validate, reason}}
 
       {:error, e} ->
-        Logger.error("Could not decode user at fetch #{ap_id}, #{inspect(e)}")
         {:error, e}
     end
   end

test/pleroma/web/activity_pub/mrf/anti_link_spam_policy_test.exs

@@ -241,11 +241,11 @@ test "it rejects posts without links" do
 
       assert capture_log(fn ->
                {:reject, _} = AntiLinkSpamPolicy.filter(message)
-             end) =~ "[error] Could not decode user at fetch http://invalid.actor"
+             end) =~ "[error] Could not fetch user http://invalid.actor,"
 
       assert capture_log(fn ->
                {:reject, _} = AntiLinkSpamPolicy.filter(update_message)
-             end) =~ "[error] Could not decode user at fetch http://invalid.actor"
+             end) =~ "[error] Could not fetch user http://invalid.actor,"
     end
 
     test "it rejects posts with links" do
@@ -259,11 +259,11 @@ test "it rejects posts with links" do
 
       assert capture_log(fn ->
                {:reject, _} = AntiLinkSpamPolicy.filter(message)
-             end) =~ "[error] Could not decode user at fetch http://invalid.actor"
+             end) =~ "[error] Could not fetch user http://invalid.actor,"
 
       assert capture_log(fn ->
                {:reject, _} = AntiLinkSpamPolicy.filter(update_message)
-             end) =~ "[error] Could not decode user at fetch http://invalid.actor"
+             end) =~ "[error] Could not fetch user http://invalid.actor,"
     end
   end
 

test/pleroma/web/activity_pub/relay_test.exs

@@ -29,7 +29,7 @@ test "relay actor is invisible" do
     test "returns errors when user not found" do
       assert capture_log(fn ->
                {:error, _} = Relay.follow("test-ap-id")
-             end) =~ "Could not decode user at fetch"
+             end) =~ "Could not fetch user test-ap-id,"
     end
 
     test "returns activity" do
@@ -48,7 +48,7 @@ test "returns activity" do
     test "returns errors when user not found" do
       assert capture_log(fn ->
                {:error, _} = Relay.unfollow("test-ap-id")
-             end) =~ "Could not decode user at fetch"
+             end) =~ "Could not fetch user test-ap-id,"
     end
 
     test "returns activity" do

test/pleroma/web/twitter_api/remote_follow_controller_test.exs

@@ -132,7 +132,7 @@ test "show follow page with error when user can not be fetched by `acct` link",
                  |> html_response(200)
 
                assert response =~ "Error fetching user"
-             end) =~ ":not_found"
+             end) =~ "User doesn't exist (anymore): https://mastodon.social/users/not_found"
     end
   end