Fix Post.fast_count("pool:1537") == 0 (fixup 134958d1).

Fixup for a bug in 134958d1. `Post.fast_count("pool:1537")` still
returned zero because `Tag.is_simple_tag?` incorrectly parsed
"pool:1537" as a simple tag, so Post.fast_count still looked for it in
the tags table and found the empty "pool:1537" tag.

app/models/tag.rb

@@ -417,8 +417,27 @@ class Tag < ApplicationRecord
 
     # true if query is a single "simple" tag (not a metatag, negated tag, or wildcard tag).
     def is_simple_tag?(query)
-      q = parse_query(query)
-      (scan_query(query).size == 1) && (q[:tags][:related].size == 1)
+      is_single_tag?(query) && !is_metatag?(query) && !is_negated_tag?(query) && !is_optional_tag?(query) && !is_wildcard_tag?(query)
+    end
+
+    def is_single_tag?(query)
+      scan_query(query).size == 1
+    end
+
+    def is_metatag?(tag)
+      !!(tag =~ /\A(#{METATAGS}):(.+)\Z/i)
+    end
+
+    def is_negated_tag?(tag)
+      tag.starts_with?("-")
+    end
+
+    def is_optional_tag?(tag)
+      tag.starts_with?("~")
+    end
+
+    def is_wildcard_tag?(tag)
+      tag.include?("*")
     end
 
     def parse_query(query, options = {})

test/unit/post_test.rb

@@ -2405,6 +2405,13 @@ class PostTest < ActiveSupport::TestCase
 
           assert_equal(100, Post.fast_count("score:42"))
         end
+
+        should "return the correct cached count for a pool:<id> search" do
+          FactoryGirl.build(:tag, name: "pool:1234", post_count: -100).save(validate: false)
+          Post.set_count_in_cache("pool:1234", 100)
+
+          assert_equal(100, Post.fast_count("pool:1234"))
+        end
       end
 
       context "a multi-tag search" do

test/unit/tag_test.rb

@@ -158,6 +158,28 @@ class TagTest < ActiveSupport::TestCase
       Tag.expects(:normalize_tags_in_query).returns(nil)
       assert_equal(["acb"], Tag.parse_query("a*b")[:tags][:include])
     end
+
+    should "parse single tags correctly" do
+      assert_equal(true, Tag.is_single_tag?("foo"))
+      assert_equal(true, Tag.is_single_tag?("-foo"))
+      assert_equal(true, Tag.is_single_tag?("~foo"))
+      assert_equal(true, Tag.is_single_tag?("foo*"))
+      assert_equal(true, Tag.is_single_tag?("fav:1234"))
+      assert_equal(true, Tag.is_single_tag?("pool:1234"))
+      assert_equal(true, Tag.is_single_tag?('source:"foo bar baz"'))
+      assert_equal(false, Tag.is_single_tag?("foo bar"))
+    end
+
+    should "parse simple tags correctly" do
+      assert_equal(true, Tag.is_simple_tag?("foo"))
+      assert_equal(false, Tag.is_simple_tag?("-foo"))
+      assert_equal(false, Tag.is_simple_tag?("~foo"))
+      assert_equal(false, Tag.is_simple_tag?("foo*"))
+      assert_equal(false, Tag.is_simple_tag?("fav:1234"))
+      assert_equal(false, Tag.is_simple_tag?("pool:1234"))
+      assert_equal(false, Tag.is_simple_tag?('source:"foo bar baz"'))
+      assert_equal(false, Tag.is_simple_tag?("foo bar"))
+    end
   end
 
   context "A tag" do