FEATURE: support group querying in created-by filter (/filter) (#35692)

Currently, there is no way to query topics `created by anyone in this
(input-group)` , with this PR we address that.

It is an overload – similar to what assign does:


https://github.com/discourse/discourse/blob/a54e3208cb1e331346d17c1687f593dcdd9eb583/plugins/discourse-assign/plugin.rb#L327-L345

I used the same tests as in
https://github.com/discourse/discourse/pull/35631

config/locales/server.en.yml

@@ -2893,9 +2893,9 @@ en:
       activity_after: "Show topics with last activity after a date (YYYY-MM-DD or days ago)"
       created_before: "Show topics created before a date (YYYY-MM-DD or days ago)"
       created_after: "Show topics created after a date (YYYY-MM-DD or days ago)"
-      created_by: "Show topics created by a specific user"
-      created_by_user: "Show topics created by username (without @)"
-      created_by_multiple: "Show topics created by any of the specified users (comma-separated)"
+      created_by: "Show topics created by a specific user or group"
+      created_by_user: "Show topics created by username or group (without @)"
+      created_by_multiple: "Show topics created by any of the specified users or groups (comma-separated)"
       latest_post_before: "Show topics with last post before a date (YYYY-MM-DD or days ago)"
       latest_post_after: "Show topics with last post after a date (YYYY-MM-DD or days ago)"
       likes_min: "Show topics with at least this many likes"

lib/topics_filter.rb

@@ -52,7 +52,7 @@ class TopicsFilter
       when "created-before"
         filter_by_created(before: filter_values)
       when "created-by"
-        filter_created_by_user(usernames: filter_values.flat_map { |value| value.split(",") })
+        filter_created_by(names: filter_values.flat_map { |value| value.split(",") })
       when "in"
         filter_in(values: filter_values)
       when "latest-post-after"
@@ -197,7 +197,7 @@ class TopicsFilter
       {
         name: "created-by:",
         description: I18n.t("filter.description.created_by"),
-        type: "username",
+        type: "username_group_list",
         delimiters: [{ name: ",", description: I18n.t("filter.description.created_by_multiple") }],
       },
       {
@@ -659,12 +659,33 @@ class TopicsFilter
       SQL
   end
 
-  def filter_created_by_user(usernames:)
-    @scope =
-      @scope.joins(:user).where(
-        "users.username_lower IN (:usernames)",
-        usernames: usernames.map(&:downcase),
-      )
+  def filter_created_by(names:)
+    if names.include?("me") && @guardian.authenticated?
+      names = names.map { |n| n == "me" ? @guardian.user.username_lower : n }
+    end
+    if (user_ids = User.where("username_lower IN (?)", names.map(&:downcase)).pluck(:id)) &&
+         user_ids.any?
+      @scope = @scope.joins(:user).where(user_id: user_ids)
+      return
+    end
+
+    if (
+         group_ids =
+           Group
+             .visible_groups(@guardian.user)
+             .where("lower(name) IN (?)", names.map(&:downcase))
+             .pluck(:id)
+       ) && group_ids.any?
+      @scope =
+        @scope
+          .joins(:user)
+          .joins("INNER JOIN group_users ON group_users.user_id = users.id")
+          .where("group_users.group_id IN (?)", group_ids)
+          .distinct(:id)
+      return
+    end
+
+    @scope = @scope.none
   end
 
   def apply_custom_filter!(scope:, filter_name:, values:)

spec/lib/topics_filter_spec.rb

@@ -1699,6 +1699,129 @@ RSpec.describe TopicsFilter do
           ).to eq([])
         end
       end
+
+      describe "when query string is `created-by:me`" do
+        it "should return the topics created by the current user" do
+          expect(
+            TopicsFilter
+              .new(guardian: Guardian.new(user))
+              .filter_from_query_string("created-by:me")
+              .pluck(:id),
+          ).to contain_exactly(topic_by_user.id, topic2_by_user.id)
+        end
+
+        it "should not return any topics when there is no current user" do
+          expect(
+            TopicsFilter
+              .new(guardian: Guardian.new)
+              .filter_from_query_string("created-by:me")
+              .pluck(:id),
+          ).to eq([])
+        end
+      end
+    end
+
+    describe "when filtering by topic creator's group" do
+      fab!(:group1) { Fabricate(:group, name: "group1") }
+      fab!(:group2) { Fabricate(:group, name: "group2") }
+      fab!(:user_in_group1) { Fabricate(:user).tap { |u| group1.add(u) } }
+      fab!(:user_in_group2) { Fabricate(:user).tap { |u| group2.add(u) } }
+      fab!(:user_in_both_groups) do
+        Fabricate(:user).tap do |u|
+          group1.add(u)
+          group2.add(u)
+        end
+      end
+      fab!(:topic_by_group1_user) { Fabricate(:topic, user: user_in_group1) }
+      fab!(:topic_by_group2_user) { Fabricate(:topic, user: user_in_group2) }
+      fab!(:topic_by_both_groups_user) { Fabricate(:topic, user: user_in_both_groups) }
+
+      describe "when query string is `created-by:group1`" do
+        it "should return topics created by users in the specified group" do
+          expect(
+            TopicsFilter
+              .new(guardian: Guardian.new)
+              .filter_from_query_string("created-by:group1")
+              .pluck(:id),
+          ).to contain_exactly(topic_by_group1_user.id, topic_by_both_groups_user.id)
+        end
+      end
+
+      describe "when query string is `created-by:group2`" do
+        it "should return topics created by users in the specified group" do
+          expect(
+            TopicsFilter
+              .new(guardian: Guardian.new)
+              .filter_from_query_string("created-by:group2")
+              .pluck(:id),
+          ).to contain_exactly(topic_by_group2_user.id, topic_by_both_groups_user.id)
+        end
+      end
+
+      describe "when query string is `created-by:group1,group2`" do
+        it "should return topics created by users in any of the specified groups" do
+          expect(
+            TopicsFilter
+              .new(guardian: Guardian.new)
+              .filter_from_query_string("created-by:group1,group2")
+              .pluck(:id),
+          ).to contain_exactly(
+            topic_by_group1_user.id,
+            topic_by_group2_user.id,
+            topic_by_both_groups_user.id,
+          )
+        end
+      end
+
+      describe "when query string is `created-by:invalid`" do
+        it "should not return any topics" do
+          expect(
+            TopicsFilter
+              .new(guardian: Guardian.new)
+              .filter_from_query_string("created-by:invalid")
+              .pluck(:id),
+          ).to eq([])
+        end
+      end
+
+      describe "when query string is `created-by:group1,invalid`" do
+        it "should only return topics created by users in the valid group" do
+          expect(
+            TopicsFilter
+              .new(guardian: Guardian.new)
+              .filter_from_query_string("created-by:group1,invalid")
+              .pluck(:id),
+          ).to contain_exactly(topic_by_group1_user.id, topic_by_both_groups_user.id)
+        end
+      end
+
+      describe "with group visibility restrictions" do
+        fab!(:private_group) do
+          Fabricate(:group, visibility_level: Group.visibility_levels[:members])
+        end
+        fab!(:user_in_private_group) { Fabricate(:user).tap { |u| private_group.add(u) } }
+        fab!(:topic_by_private_group_user) { Fabricate(:topic, user: user_in_private_group) }
+
+        it "should not return topics when user cannot see the group" do
+          expect(
+            TopicsFilter
+              .new(guardian: Guardian.new)
+              .filter_from_query_string("created-by:#{private_group.name}")
+              .pluck(:id),
+          ).to eq([])
+        end
+
+        it "should return topics when user is a member of the private group" do
+          private_group.add(user)
+
+          expect(
+            TopicsFilter
+              .new(guardian: Guardian.new(user))
+              .filter_from_query_string("created-by:#{private_group.name}")
+              .pluck(:id),
+          ).to contain_exactly(topic_by_private_group_user.id)
+        end
+      end
     end
 
     shared_examples "filtering for topics by counts" do |filter|