FIX: Sensitivity did not work by default

Forums without previously calculated scores would return the same values
for low/medium/high sensitivity. Now those are scaled based on the
default value.

The default value has also been changed from 10.0 to 12.5 based on
observing data from live discourse forums.

app/models/reviewable.rb

@@ -78,6 +78,12 @@ class Reviewable < ActiveRecord::Base
     )
   end
 
+  # This number comes from looking at forums in the wild and what numbers work.
+  # As the site accumulates real data it'll be based on the site activity instead.
+  def self.typical_sensitivity
+    12.5
+  end
+
   # Generate `pending?`, `rejected?`, etc helper methods
   statuses.each do |name, id|
     define_method("#{name}?") { status == id }
@@ -195,11 +201,13 @@ class Reviewable < ActiveRecord::Base
     return Float::MAX if sensitivity == 0
 
     ratio = sensitivity / Reviewable.sensitivity[:low].to_f
-    high = PluginStore.get('reviewables', "priority_#{Reviewable.priorities[:high]}")
-    return (10.0 * scale) if high.nil?
+    high = (
+      PluginStore.get('reviewables', "priority_#{Reviewable.priorities[:high]}") ||
+      typical_sensitivity
+    ).to_f
 
     # We want this to be hard to reach
-    (high.to_f * ratio) * scale
+    ((high.to_f * ratio) * scale).truncate(2)
   end
 
   def self.sensitivity_score(sensitivity, scale: 1.0)

lib/post_action_creator.rb

@@ -155,6 +155,7 @@ private
   def auto_hide_if_needed
     return if @post.hidden?
     return if !@created_by.staff? && @post.user&.staff?
+    return unless PostActionType.auto_action_flag_types.include?(@post_action_name)
 
     # Special case: If you have TL3 and the user is TL0, and the flag is spam,
     # hide it immediately.
@@ -163,13 +164,13 @@ private
         @post.user&.trust_level == TrustLevel[0]
       @post.hide!(@post_action_type_id, Post.hidden_reasons[:flagged_by_tl3_user])
       return
-    elsif PostActionType.auto_action_flag_types.include?(@post_action_name)
+    end
+
     score = ReviewableFlaggedPost.find_by(target: @post)&.score || 0
     if score >= Reviewable.score_required_to_hide_post
       @post.hide!(@post_action_type_id)
     end
   end
-  end
 
   def create_post_action
     @targets_topic = !!(

spec/models/reviewable_spec.rb

@@ -339,11 +339,13 @@ RSpec.describe Reviewable, type: :model do
       expect(Reviewable.score_required_to_hide_post).to eq(40.0)
     end
 
-    it "returns 10 if we can't calculated any percentiles" do
+    it "returns a default if we can't calculated any percentiles" do
       SiteSetting.hide_post_sensitivity = Reviewable.sensitivity[:low]
-      expect(Reviewable.score_required_to_hide_post).to eq(10.0)
+      expect(Reviewable.score_required_to_hide_post).to eq(12.5)
       SiteSetting.hide_post_sensitivity = Reviewable.sensitivity[:medium]
-      expect(Reviewable.score_required_to_hide_post).to eq(10.0)
+      expect(Reviewable.score_required_to_hide_post).to eq(8.33)
+      SiteSetting.hide_post_sensitivity = Reviewable.sensitivity[:high]
+      expect(Reviewable.score_required_to_hide_post).to eq(4.16)
     end
 
     it "returns a fraction of the high percentile" do
@@ -360,37 +362,37 @@ RSpec.describe Reviewable, type: :model do
   end
 
   context ".spam_score_to_silence_new_user" do
-    it "returns 6 if we can't calculated any percentiles" do
+    it "returns a default value if we can't calculated any percentiles" do
       SiteSetting.silence_new_user_sensitivity = Reviewable.sensitivity[:low]
-      expect(Reviewable.spam_score_to_silence_new_user).to eq(6.0)
+      expect(Reviewable.spam_score_to_silence_new_user).to eq(7.5)
       SiteSetting.silence_new_user_sensitivity = Reviewable.sensitivity[:medium]
-      expect(Reviewable.spam_score_to_silence_new_user).to eq(6.0)
+      expect(Reviewable.spam_score_to_silence_new_user).to eq(4.99)
       SiteSetting.silence_new_user_sensitivity = Reviewable.sensitivity[:high]
-      expect(Reviewable.spam_score_to_silence_new_user).to eq(6.0)
+      expect(Reviewable.spam_score_to_silence_new_user).to eq(2.49)
     end
 
     it "returns a fraction of the high percentile" do
       Reviewable.set_priorities(high: 100.0)
       SiteSetting.silence_new_user_sensitivity = Reviewable.sensitivity[:disabled]
-      expect(Reviewable.spam_score_to_silence_new_user.to_f.truncate(2)).to eq(Float::MAX)
+      expect(Reviewable.spam_score_to_silence_new_user.to_f).to eq(Float::MAX)
       SiteSetting.silence_new_user_sensitivity = Reviewable.sensitivity[:low]
-      expect(Reviewable.spam_score_to_silence_new_user.to_f.truncate(2)).to eq(60.0)
+      expect(Reviewable.spam_score_to_silence_new_user.to_f).to eq(60.0)
       SiteSetting.silence_new_user_sensitivity = Reviewable.sensitivity[:medium]
-      expect(Reviewable.spam_score_to_silence_new_user.to_f.truncate(2)).to eq(39.99)
+      expect(Reviewable.spam_score_to_silence_new_user.to_f).to eq(39.99)
       SiteSetting.silence_new_user_sensitivity = Reviewable.sensitivity[:high]
-      expect(Reviewable.spam_score_to_silence_new_user.to_f.truncate(2)).to eq(19.99)
+      expect(Reviewable.spam_score_to_silence_new_user.to_f).to eq(19.99)
     end
   end
 
   context ".score_to_auto_close_topic" do
 
-    it "returns 25 if we can't calculated any percentiles" do
+    it "returns the default if we can't calculated any percentiles" do
       SiteSetting.auto_close_topic_sensitivity = Reviewable.sensitivity[:low]
-      expect(Reviewable.score_to_auto_close_topic).to eq(25.0)
+      expect(Reviewable.score_to_auto_close_topic).to eq(31.25)
       SiteSetting.auto_close_topic_sensitivity = Reviewable.sensitivity[:medium]
-      expect(Reviewable.score_to_auto_close_topic).to eq(25.0)
+      expect(Reviewable.score_to_auto_close_topic).to eq(20.83)
       SiteSetting.auto_close_topic_sensitivity = Reviewable.sensitivity[:high]
-      expect(Reviewable.score_to_auto_close_topic).to eq(25.0)
+      expect(Reviewable.score_to_auto_close_topic).to eq(10.41)
     end
 
     it "returns a fraction of the high percentile" do