PERF: bail out of expensive post validations

Whenever a post already failed "lightweight" validations, we skip all the expensive validations (that cooks the post or run SQL queries) so that we reply as soon as possible.

Also skip validating polls when there's no "[/poll]" in the raw.

Internal ref - t/115890

lib/validators/post_validator.rb

@@ -4,27 +4,27 @@ class PostValidator < ActiveModel::Validator
   def validate(record)
     presence(record)
 
-    return if record.acting_user.try(:staged?)
-    if record.acting_user.try(:admin?) && Discourse.static_doc_topic_ids.include?(record.topic_id)
-      return
-    end
+    return if record.acting_user&.staged?
+    return if record.acting_user&.admin? && Discourse.static_doc_topic_ids.include?(record.topic_id)
 
     post_body_validator(record)
     max_posts_validator(record)
-    max_mention_validator(record)
-    max_embedded_media_validator(record)
-    max_attachments_validator(record)
-    can_post_links_validator(record)
     unique_post_validator(record)
-    force_edit_last_validator(record)
+
+    # These validators might cook the post or do SQL queries.
+    # So we only run them if the post is otherwise valid.
+    if record.errors.empty?
+      max_mention_validator(record)
+      max_embedded_media_validator(record)
+      max_attachments_validator(record)
+      max_links_validator(record)
+      force_edit_last_validator(record)
+    end
   end
 
   def presence(post)
-    unless options[:skip_topic]
-      post.errors.add(:topic_id, :blank, **options) if post.topic_id.blank?
-    end
-
-    post.errors.add(:user_id, :blank, **options) if post.new_record? && post.user_id.nil?
+    post.errors.add(:topic_id, :blank, **options) if !options[:skip_topic] && post.topic_id.blank?
+    post.errors.add(:user_id, :blank, **options) if post.new_record? && post.user_id.blank?
   end
 
   def post_body_validator(post)
@@ -37,31 +37,40 @@ class PostValidator < ActiveModel::Validator
   def stripped_length(post)
     range =
       if private_message?(post)
-        # private message
         SiteSetting.private_message_post_length
       elsif post.is_first_post? || (post.topic.present? && post.topic.posts_count == 0)
-        # creating/editing first post
         if post.topic&.featured_link&.present?
           (0..SiteSetting.max_post_length)
         else
           SiteSetting.first_post_length
         end
       else
-        # regular post
         SiteSetting.post_length
       end
 
     StrippedLengthValidator.validate(post, :raw, post.raw, range)
   end
 
-  def raw_quality(post)
-    sentinel = TextSentinel.body_sentinel(post.raw, private_message: private_message?(post))
-    post.errors.add(:raw, I18n.t(:is_invalid)) unless sentinel.valid?
+  def max_posts_validator(post)
+    if post.new_record? && post.acting_user&.posted_too_much_in_topic?(post.topic_id)
+      post.errors.add(
+        :base,
+        I18n.t(:too_many_replies, count: SiteSetting.newuser_max_replies_per_topic),
+      )
+    end
+  end
+
+  def unique_post_validator(post)
+    return if SiteSetting.unique_posts_mins == 0
+    return if post.skip_unique_check
+    return if post.acting_user&.staff?
+    return if post.raw.blank?
+
+    post.errors.add(:raw, I18n.t(:just_posted_that)) if post.matches_recent_post?
   end
 
-  # Ensure maximum amount of mentions in a post
   def max_mention_validator(post)
-    return if post.acting_user.try(:staff?)
+    return if post.acting_user&.staff?
 
     if acting_user_is_trusted?(post) || private_message?(post)
       add_error_if_count_exceeded(
@@ -82,19 +91,9 @@ class PostValidator < ActiveModel::Validator
     end
   end
 
-  def max_posts_validator(post)
-    if post.new_record? && post.acting_user.present? &&
-         post.acting_user.posted_too_much_in_topic?(post.topic_id)
-      post.errors.add(
-        :base,
-        I18n.t(:too_many_replies, count: SiteSetting.newuser_max_replies_per_topic),
-      )
-    end
-  end
-
-  # Ensure new users can not put too many media embeds (images, video, audio) in a post
   def max_embedded_media_validator(post)
-    return if post.acting_user.blank? || post.acting_user&.staff?
+    return if post.acting_user.nil?
+    return if post.acting_user.staff?
 
     if !post.acting_user.in_any_groups?(SiteSetting.embedded_media_post_allowed_groups_map)
       add_error_if_count_exceeded(
@@ -115,9 +114,9 @@ class PostValidator < ActiveModel::Validator
     end
   end
 
-  # Ensure new users can not put too many attachments in a post
   def max_attachments_validator(post)
     return if acting_user_is_trusted?(post) || private_message?(post)
+
     add_error_if_count_exceeded(
       post,
       :no_attachments_allowed,
@@ -127,7 +126,7 @@ class PostValidator < ActiveModel::Validator
     )
   end
 
-  def can_post_links_validator(post)
+  def max_links_validator(post)
     if (post.link_count == 0 && !post.has_oneboxes?) || private_message?(post)
       return newuser_links_validator(post)
     end
@@ -140,35 +139,11 @@ class PostValidator < ActiveModel::Validator
     post.errors.add(:base, I18n.t(:links_require_trust))
   end
 
-  # Ensure new users can not put too many links in a post
-  def newuser_links_validator(post)
-    return if acting_user_is_trusted?(post) || private_message?(post)
-    add_error_if_count_exceeded(
-      post,
-      :no_links_allowed,
-      :too_many_links,
-      post.link_count,
-      SiteSetting.newuser_max_links,
-    )
-  end
-
-  # Stop us from posting the same thing too quickly
-  def unique_post_validator(post)
-    return if SiteSetting.unique_posts_mins == 0
-    return if post.skip_unique_check
-    return if post.acting_user.try(:staff?)
-
-    # If the post is empty, default to the validates_presence_of
-    return if post.raw.blank?
-
-    post.errors.add(:raw, I18n.t(:just_posted_that)) if post.matches_recent_post?
-  end
-
   def force_edit_last_validator(post)
-    if SiteSetting.max_consecutive_replies == 0 || post.id || post.acting_user&.staff? ||
-         private_message?(post)
-      return
-    end
+    return if post.id
+    return if private_message?(post)
+    return if post.acting_user&.staff?
+    return if SiteSetting.max_consecutive_replies == 0
 
     topic = post.topic
     return if topic&.ordered_posts&.first&.user == post.user
@@ -207,12 +182,29 @@ class PostValidator < ActiveModel::Validator
 
   private
 
+  def raw_quality(post)
+    return if TextSentinel.body_sentinel(post.raw, private_message: private_message?(post)).valid?
+    post.errors.add(:raw, I18n.t(:is_invalid))
+  end
+
   def acting_user_is_trusted?(post, level = 1)
-    post.acting_user.present? && post.acting_user.has_trust_level?(TrustLevel[level])
+    post.acting_user&.has_trust_level?(TrustLevel[level])
   end
 
   def private_message?(post)
-    post.topic.try(:private_message?) || options[:private_message]
+    post.topic&.private_message? || options[:private_message]
+  end
+
+  def newuser_links_validator(post)
+    return if acting_user_is_trusted?(post) || private_message?(post)
+
+    add_error_if_count_exceeded(
+      post,
+      :no_links_allowed,
+      :too_many_links,
+      post.link_count,
+      SiteSetting.newuser_max_links,
+    )
   end
 
   def add_error_if_count_exceeded(

lib/validators/stripped_length_validator.rb

@@ -2,7 +2,7 @@
 
 class StrippedLengthValidator < ActiveModel::EachValidator
   def self.validate(record, attribute, value, range)
-    if value.nil?
+    if value.blank?
       record.errors.add attribute, I18n.t("errors.messages.blank")
     elsif value.length > range.end
       record.errors.add attribute,