search: apply aliases after parsing searches.

Make PostQueryBuilder apply aliases earlier, immediately after parsing
the search.

On the post index page there are multiple places where we need to apply
aliases:

* When running the search with PostQueryBuilder#build.
* When calculating the search count with PostQueryBuilder#fast_count.
* When calculating the related tags for the sidebar.
* When tracking missed searches and popular searches for Reportbooru.
* When looking up wiki excerpts.

Applying aliases after parsing ensures we only have to apply aliases
once for all of these things.

We also normalize the order of tags in searches and strip repeated tags.
This is so that we have consistent cache keys for fast_count.

* Fixes searches for aliased tags being counted as missed searches (fixes #4433).
* Fixes wiki excerpts not showing up when searching for aliased tags.

app/models/post.rb

@@ -604,7 +604,7 @@ class Post < ApplicationRecord
         # If someone else committed changes to this post before we did,
         # then try to merge the tag changes together.
         current_tags = tag_string_was.split
-        new_tags = PostQueryBuilder.new(tag_string).split_query
+        new_tags = PostQueryBuilder.new(tag_string, normalize_aliases: false).parse_tag_edit
         old_tags = old_tag_string.split
 
         kept_tags = current_tags & new_tags
@@ -642,7 +642,7 @@ class Post < ApplicationRecord
     end
 
     def normalize_tags
-      normalized_tags = PostQueryBuilder.new(tag_string).split_query
+      normalized_tags = PostQueryBuilder.new(tag_string, normalize_aliases: false).parse_tag_edit
       normalized_tags = apply_casesensitive_metatags(normalized_tags)
       normalized_tags = normalized_tags.map(&:downcase)
       normalized_tags = filter_metatags(normalized_tags)

app/models/saved_search.rb

@@ -134,17 +134,17 @@ class SavedSearch < ApplicationRecord
       def queries_for(user_id, label: nil, options: {})
         searches = SavedSearch.where(user_id: user_id)
         searches = searches.labeled(label) if label.present?
-        queries = searches.pluck(:query).map { |query| PostQueryBuilder.new(query).normalize_query(normalize_aliases: true, sort: true) }
+        queries = searches.pluck(:query).map { |query| PostQueryBuilder.new(query).to_s }
         queries.sort.uniq
       end
     end
 
     def normalized_query
-      PostQueryBuilder.new(query).normalize_query(sort: true)
+      PostQueryBuilder.new(query, normalize_aliases: false).to_s
     end
 
     def normalize_query
-      self.query = PostQueryBuilder.new(query).normalize_query(normalize_aliases: true, sort: false)
+      self.query = PostQueryBuilder.new(query, normalize_order: false).to_s
     end
   end
 

app/models/upload.rb

@@ -237,7 +237,7 @@ class Upload < ApplicationRecord
   include SourceMethods
 
   def assign_rating_from_tags
-    if rating = PostQueryBuilder.new(tag_string).find_metatag(:rating)
+    if rating = PostQueryBuilder.new(tag_string, normalize_aliases: false).find_metatag(:rating)
       self.rating = rating.downcase.first
     end
   end