Add validity for PostgreSQL indexes

activerecord/CHANGELOG.md

@@ -1,3 +1,12 @@
+*   Add validity for PostgreSQL indexes.
+
+    ```ruby
+    connection.index_exists?(:users, :email, valid: true)
+    connection.indexes(:users).select(&:valid?)
+    ```
+
+    *fatkodima*
+
 *   Fix eager loading for models without primary keys.
 
     *Anmol Chopra*, *Matt Lawrence*, and *Jonathan Hefner*

activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb

@@ -6,7 +6,7 @@ module ConnectionAdapters # :nodoc:
     # this type are typically created and returned by methods in database
     # adapters. e.g. ActiveRecord::ConnectionAdapters::MySQL::SchemaStatements#indexes
     class IndexDefinition # :nodoc:
-      attr_reader :table, :name, :unique, :columns, :lengths, :orders, :opclasses, :where, :type, :using, :comment
+      attr_reader :table, :name, :unique, :columns, :lengths, :orders, :opclasses, :where, :type, :using, :comment, :valid
 
       def initialize(
         table, name,
@@ -18,7 +18,8 @@ def initialize(
         where: nil,
         type: nil,
         using: nil,
-        comment: nil
+        comment: nil,
+        valid: true
       )
         @table = table
         @name = name
@@ -31,6 +32,11 @@ def initialize(
         @type = type
         @using = using
         @comment = comment
+        @valid = valid
+      end
+
+      def valid?
+        @valid
       end
 
       def column_options
@@ -41,6 +47,13 @@ def column_options
         }
       end
 
+      def defined_for?(columns = nil, name: nil, unique: nil, valid: nil, **options)
+        (columns.nil? || Array(self.columns) == Array(columns).map(&:to_s)) &&
+          (name.nil? || self.name == name.to_s) &&
+          (unique.nil? || self.unique == unique) &&
+          (valid.nil? || self.valid == valid)
+      end
+
       private
         def concise_options(options)
           if columns.size == options.size && options.values.uniq.size == 1

activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb

@@ -96,18 +96,11 @@ def indexes(table_name)
       #   # Check an index with a custom name exists
       #   index_exists?(:suppliers, :company_id, name: "idx_company_id")
       #
+      #   # Check a valid index exists (PostgreSQL only)
+      #   index_exists?(:suppliers, :company_id, valid: true)
+      #
       def index_exists?(table_name, column_name, **options)
-        checks = []
-
-        if column_name.present?
-          column_names = Array(column_name).map(&:to_s)
-          checks << lambda { |i| Array(i.columns) == column_names }
-        end
-
-        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] } }
+        indexes(table_name).any? { |i| i.defined_for?(column_name, **options) }
       end
 
       # Returns an array of +Column+ objects for the table specified by +table_name+.

activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb

@@ -88,7 +88,7 @@ def indexes(table_name) # :nodoc:
 
           result = query(<<~SQL, "SCHEMA")
             SELECT distinct i.relname, d.indisunique, d.indkey, pg_get_indexdef(d.indexrelid), t.oid,
-                            pg_catalog.obj_description(i.oid, 'pg_class') AS comment
+                            pg_catalog.obj_description(i.oid, 'pg_class') AS comment, d.indisvalid
             FROM pg_class t
             INNER JOIN pg_index d ON t.oid = d.indrelid
             INNER JOIN pg_class i ON d.indexrelid = i.oid
@@ -107,6 +107,7 @@ def indexes(table_name) # :nodoc:
             inddef = row[3]
             oid = row[4]
             comment = row[5]
+            valid = row[6]
 
             using, expressions, where = inddef.scan(/ USING (\w+?) \((.+?)\)(?: WHERE (.+))?\z/m).flatten
 
@@ -144,7 +145,8 @@ def indexes(table_name) # :nodoc:
               opclasses: opclasses,
               where: where,
               using: using.to_sym,
-              comment: comment.presence
+              comment: comment.presence,
+              valid: valid
             )
           end
         end

activerecord/test/cases/adapters/postgresql/postgresql_adapter_test.rb

@@ -322,6 +322,20 @@ def test_index_with_opclass
         end
       end
 
+      def test_invalid_index
+        with_example_table do
+          @connection.exec_query("INSERT INTO ex (number) VALUES (1), (1)")
+          error = assert_raises(ActiveRecord::RecordNotUnique) do
+            @connection.add_index(:ex, :number, unique: true, algorithm: :concurrently, name: :invalid_index)
+          end
+          assert_match(/could not create unique index/, error.message)
+
+          assert @connection.index_exists?(:ex, :number, name: :invalid_index)
+          assert_not @connection.index_exists?(:ex, :number, name: :invalid_index, valid: true)
+          assert @connection.index_exists?(:ex, :number, name: :invalid_index, valid: false)
+        end
+      end
+
       def test_columns_for_distinct_zero_orders
         assert_equal "posts.id",
           @connection.columns_for_distinct("posts.id", [])