Ignore index name in `index_exists?` when not passed a name to check for

4 files changed, 19 insertions, 2 deletions

diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index 87420a0746..781b786012 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,3 +1,8 @@
+*   Ignore index name in `index_exists?` and `remove_index` when not passed a
+    name to check for.
+
+    *Grey Baker*
+
 *   Version the API presented to migration classes, so we can change parameter
     defaults without breaking existing migrations, or forcing them to be
     rewritten through a deprecation cycle.
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
index b50d28862c..93f0d9d0e7 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
@@ -82,11 +82,10 @@ module ActiveRecord
       #
       def index_exists?(table_name, column_name, options = {})
         column_names = Array(column_name).map(&:to_s)
-        index_name = options.key?(:name) ? options[:name].to_s : index_name(table_name, column: column_names)
         checks = []
-        checks << lambda { |i| i.name == index_name }
         checks << lambda { |i| i.columns == column_names }
         checks << lambda { |i| i.unique } if options[:unique]
+        checks << lambda { |i| i.name == options[:name].to_s } if options[:name]
 
         indexes(table_name).any? { |i| checks.all? { |check| check[i] } }
       end
diff --git a/activerecord/lib/active_record/migration/compatibility.rb b/activerecord/lib/active_record/migration/compatibility.rb
index 4c8db8a2d5..bc5b97a711 100644
--- a/activerecord/lib/active_record/migration/compatibility.rb
+++ b/activerecord/lib/active_record/migration/compatibility.rb
@@ -28,6 +28,17 @@ module ActiveRecord
           options[:null] = true if options[:null].nil?
           super
         end
+
+        def index_exists?(table_name, column_name, options = {})
+          column_names = Array(column_name).map(&:to_s)
+          options[:name] =
+            if options.key?(:name).present?
+              options[:name].to_s
+            else
+              index_name(table_name, column: column_names)
+            end
+          super
+        end
       end
 
       class V4_2 < V5_0
diff --git a/activerecord/test/cases/migration/index_test.rb b/activerecord/test/cases/migration/index_test.rb
index b23b9a679f..70169e501c 100644
--- a/activerecord/test/cases/migration/index_test.rb
+++ b/activerecord/test/cases/migration/index_test.rb
@@ -130,7 +130,9 @@ module ActiveRecord
       def test_named_index_exists
         connection.add_index :testings, :foo, :name => "custom_index_name"
 
+        assert connection.index_exists?(:testings, :foo)
         assert connection.index_exists?(:testings, :foo, :name => "custom_index_name")
+        assert !connection.index_exists?(:testings, :foo, :name => "other_index_name")
       end
 
       def test_add_index_attribute_length_limit