FEATURE: Change very high/low search priority to rank at absolute ends.

Prior to this change, we had weights for very_high, high, low and
very_low. This means there were 4 weights to tweak and what weights to
use for `very_high/high` and `very_low/low` pair was hard to explain.
This change makes it such that `very_high` search priority will always
ensure that the posts are ranked at the top while `very_low` search
priority will ensure that the posts are ranked at the very bottom.

config/locales/server.en.yml

@@ -1470,10 +1470,8 @@ en:
     search_query_log_max_size: "Maximum amount of search queries to keep"
     search_query_log_max_retention_days: "Maximum amount of time to keep search queries, in days."
     search_ignore_accents: "Ignore accents when searching for text."
-    category_search_priority_very_low_weight: "Weight applied to ranking for very low category search priority."
     category_search_priority_low_weight: "Weight applied to ranking for low category search priority."
     category_search_priority_high_weight: "Weight applied to ranking for high category search priority."
-    category_search_priority_very_high_weight: "Weight applied to ranking for very high category search priority."
     allow_uncategorized_topics: "Allow topics to be created without a category. WARNING: If there are any uncategorized topics, you must recategorize them before turning this off."
     allow_duplicate_topic_titles: "Allow topics with identical, duplicate titles."
     allow_duplicate_topic_titles_category: "Allow topics with identical, duplicate titles if the category is different. allow_duplicate_topic_titles must be false."
@@ -2329,10 +2327,8 @@ en:
       invalid_hex_value: "Color values have to be 6-digit hexadecimal codes."
       empty_selectable_avatars: "You must first upload at least two selectable avatars before enabling this setting."
       category_search_priority:
-        very_low_weight_invalid: "You cannot set the weight to be greater than 'category_search_priority_low_weight'."
+        low_weight_invalid: "You cannot set the weight to be greater or equal to 1."
-        low_weight_invalid: "You cannot set the weight to be greater or equal to 1 or smaller than 'category_search_priority_very_low_weight'."
+        high_weight_invalid: "You cannot set the weight to be smaller or equal to 1."
-        high_weight_invalid: "You cannot set the weight to be smaller or equal to 1 or greater than 'category_search_priority_very_high_weight'."
-        very_high_weight_invalid: "You cannot set the weight to be smaller than 'category_search_priority_high_weight'."
       allowed_unicode_usernames:
         regex_invalid: "The regular expression is invalid: %{error}"
         leading_trailing_slash: "The regular expression must not start and end with a slash."

config/site_settings.yml

@@ -1950,10 +1950,6 @@ search:
       ro: true
       sk: true
       tr_TR: true
-  category_search_priority_very_low_weight:
-    default: 0.6
-    hidden: true
-    validator: "CategorySearchPriorityWeightsValidator"
   category_search_priority_low_weight:
     default: 0.8
     hidden: true
@@ -1962,10 +1958,6 @@ search:
     default: 1.2
     hidden: true
     validator: "CategorySearchPriorityWeightsValidator"
-  category_search_priority_very_high_weight:
-    default: 1.4
-    hidden: true
-    validator: "CategorySearchPriorityWeightsValidator"
 
 uncategorized:
   version_checks:

db/migrate/20201223071241_delete_stale_category_search_priorities_from_site_settings.rb

@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+class DeleteStaleCategorySearchPrioritiesFromSiteSettings < ActiveRecord::Migration[6.0]
+  def up
+    execute <<~SQL
+    DELETE FROM site_settings WHERE name IN ('category_search_priority_very_low_weight', 'category_search_priority_very_high_weight')
+    SQL
+  end
+
+  def down
+    raise ActiveRecord::IrreversibleMigration
+  end
+end

lib/search.rb

@@ -1019,17 +1019,25 @@ class Search
       )
       SQL
 
+      category_search_priority = <<~SQL
+      (
+        CASE categories.search_priority
+        WHEN #{Searchable::PRIORITIES[:very_high]}
+        THEN 3
+        WHEN #{Searchable::PRIORITIES[:very_low]}
+        THEN 1
+        ELSE 2
+        END
+      )
+      SQL
+
       category_priority_weights = <<~SQL
       (
         CASE categories.search_priority
-        WHEN #{Searchable::PRIORITIES[:very_low]}
-        THEN #{SiteSetting.category_search_priority_very_low_weight}
         WHEN #{Searchable::PRIORITIES[:low]}
         THEN #{SiteSetting.category_search_priority_low_weight}
         WHEN #{Searchable::PRIORITIES[:high]}
         THEN #{SiteSetting.category_search_priority_high_weight}
-        WHEN #{Searchable::PRIORITIES[:very_high]}
-        THEN #{SiteSetting.category_search_priority_very_high_weight}
         ELSE
           CASE WHEN topics.closed
           THEN 0.9
@@ -1048,9 +1056,9 @@ class Search
 
       posts =
         if aggregate_search
-          posts.order("MAX(#{data_ranking}) DESC")
+          posts.order("MAX(#{category_search_priority}) DESC", "MAX(#{data_ranking}) DESC")
         else
-          posts.order("#{data_ranking} DESC")
+          posts.order("#{category_search_priority} DESC", "#{data_ranking} DESC")
         end
 
       posts = posts.order("topics.bumped_at DESC")

lib/validators/category_search_priority_weights_validator.rb

@@ -9,14 +9,10 @@ class CategorySearchPriorityWeightsValidator
     val = val.to_f
 
     case @name
-    when "category_search_priority_very_low_weight"
-      val < SiteSetting.category_search_priority_low_weight
     when "category_search_priority_low_weight"
-      val < 1 && val > SiteSetting.category_search_priority_very_low_weight
+      val < 1
     when "category_search_priority_high_weight"
-      val > 1 && val < SiteSetting.category_search_priority_very_high_weight
+      val > 1
-    when "category_search_priority_very_high_weight"
-      val > SiteSetting.category_search_priority_high_weight
     end
   end
 

spec/components/validators/category_search_priority_weights_validator_spec.rb

@@ -5,24 +5,16 @@ require 'validators/category_search_priority_weights_validator'
 
 RSpec.describe CategorySearchPriorityWeightsValidator do
   it "should validate the results correctly" do
-    expect do
+    [1, 1.1].each do |value|
-      SiteSetting.category_search_priority_very_low_weight = 0.9
-    end.to raise_error(Discourse::InvalidParameters)
-
-    [1, 0].each do |value|
       expect do
         SiteSetting.category_search_priority_low_weight = value
       end.to raise_error(Discourse::InvalidParameters)
     end
 
-    ['0.2', 10].each do |value|
+    [1, "0.9"].each do |value|
       expect do
         SiteSetting.category_search_priority_high_weight = value
       end.to raise_error(Discourse::InvalidParameters)
     end
-
-    expect do
-      SiteSetting.category_search_priority_very_high_weight = 1.1
-    end.to raise_error(Discourse::InvalidParameters)
   end
 end

spec/requests/search_controller_spec.rb

@@ -448,66 +448,100 @@ describe SearchController do
   end
 
   context "search priority" do
-    fab!(:low_priority_category) do
+    fab!(:very_low_priority_category) do
       Fabricate(
         :category,
         search_priority: Searchable::PRIORITIES[:very_low]
       )
     end
+
+    fab!(:low_priority_category) do
+      Fabricate(
+        :category,
+        search_priority: Searchable::PRIORITIES[:low]
+      )
+    end
+
     fab!(:high_priority_category) do
       Fabricate(
         :category,
         search_priority: Searchable::PRIORITIES[:high]
       )
     end
+
     fab!(:very_high_priority_category) do
       Fabricate(
         :category,
         search_priority: Searchable::PRIORITIES[:very_high]
       )
     end
+
+    fab!(:very_low_priority_topic) { Fabricate(:topic, category: very_low_priority_category) }
     fab!(:low_priority_topic) { Fabricate(:topic, category: low_priority_category) }
     fab!(:high_priority_topic) { Fabricate(:topic, category: high_priority_category) }
     fab!(:very_high_priority_topic) { Fabricate(:topic, category: very_high_priority_category) }
+
+    fab!(:very_low_priority_post) do
+      SearchIndexer.enable
+      Fabricate(:post, topic: very_low_priority_topic, raw: "This is a very Low Priority Post")
+    end
+
     fab!(:low_priority_post) do
       SearchIndexer.enable
-      Fabricate(:post, topic: low_priority_topic, raw: "This is a Low Priority Post")
+
+      Fabricate(:post,
+        topic: low_priority_topic,
+        raw: "This is a Low Priority Post",
+        created_at: 1.day.ago,
+      )
     end
-    fab!(:hight_priority_post) do
+
+    fab!(:high_priority_post) do
       SearchIndexer.enable
       Fabricate(:post, topic: high_priority_topic, raw: "This is a High Priority Post")
     end
-    fab!(:old_very_hight_priority_post) do
+
+    fab!(:very_high_priority_post) do
       SearchIndexer.enable
-      Fabricate(:old_post, topic: very_high_priority_topic, raw: "This is a Old but Very High Priority Post")
+
+      Fabricate(:post,
+        topic: very_high_priority_topic,
+        raw: "This is a Old but Very High Priority Post",
+        created_at: 2.days.ago,
+      )
     end
 
     it "sort posts with search priority when search term is empty" do
       get "/search.json", params: { q: 'status:open' }
       expect(response.status).to eq(200)
       data = response.parsed_body
-      post1 = data["posts"].find { |e| e["id"] == old_very_hight_priority_post.id }
+      post1 = data["posts"].find { |e| e["id"] == very_high_priority_post.id }
-      post2 = data["posts"].find { |e| e["id"] == low_priority_post.id }
+      post2 = data["posts"].find { |e| e["id"] == very_low_priority_post.id }
-      expect(data["posts"][0]["id"]).to eq(old_very_hight_priority_post.id)
+      expect(data["posts"][0]["id"]).to eq(very_high_priority_post.id)
       expect(post1["id"]).to be > post2["id"]
     end
 
     it "sort posts with search priority when no order query" do
+      SiteSetting.category_search_priority_high_weight = 999999
+      SiteSetting.category_search_priority_low_weight = 0
+
       get "/search.json", params: { q: 'status:open Priority Post' }
       expect(response.status).to eq(200)
       data = response.parsed_body
-      expect(data["posts"][0]["id"]).to eq(old_very_hight_priority_post.id)
+      expect(data["posts"][0]["id"]).to eq(very_high_priority_post.id)
-      expect(data["posts"][1]["id"]).to eq(hight_priority_post.id)
+      expect(data["posts"][1]["id"]).to eq(high_priority_post.id)
       expect(data["posts"][2]["id"]).to eq(low_priority_post.id)
+      expect(data["posts"][3]["id"]).to eq(very_low_priority_post.id)
     end
 
     it "doesn't sort posts with search piority when query with order" do
       get "/search.json", params: { q: 'status:open order:latest Priority Post' }
       expect(response.status).to eq(200)
       data = response.parsed_body
-      expect(data["posts"][0]["id"]).to eq(hight_priority_post.id)
+      expect(data["posts"][0]["id"]).to eq(high_priority_post.id)
-      expect(data["posts"][1]["id"]).to eq(low_priority_post.id)
+      expect(data["posts"][1]["id"]).to eq(very_low_priority_post.id)
-      expect(data["posts"][2]["id"]).to eq(old_very_hight_priority_post.id)
+      expect(data["posts"][2]["id"]).to eq(low_priority_post.id)
+      expect(data["posts"][3]["id"]).to eq(very_high_priority_post.id)
     end
   end