Do not consider PG array columns as number or text columns

The code uses these checks in several places to know what to do with a
particular column, for instance AR attribute query methods has a branch
like this:

    if column.number?
      !value.zero?
    end

This should never be true for array columns, since it would be the same
as running [].zero?, which results in a NoMethodError exception.

Fixing this by ensuring that array columns in PostgreSQL never return
true for number?/text? checks.

Since most of the array support was based on the postgres_ext lib, it's
worth noting it does the same thing for numeric array columns too:

https://github.com/dockyard/postgres_ext/blob/v1.0.0/lib/postgres_ext/active_record/connection_adapters/postgres_adapter.rb#L72

This extended the same logic for text columns to ensure consistency.

3 files changed, 33 insertions, 3 deletions

diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index 6d130ab4d6..45dfeddba8 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,3 +1,21 @@
+*   Do not consider PostgreSQL array columns as number or text columns.
+
+    The code uses these checks in several places to know what to do with a
+    particular column, for instance AR attribute query methods has a branch
+    like this:
+
+        if column.number?
+          !value.zero?
+        end
+
+    This should never be true for array columns, since it would be the same
+    as running [].zero?, which results in a NoMethodError exception.
+
+    Fixing this by ensuring that array columns in PostgreSQL never return
+    true for number?/text? checks.
+
+    *Carlos Antonio da Silva*
+
 *   When connecting to a non-existant postgresql database, the error:
     `ActiveRecord::NoDatabaseError` will now be raised. When being used with Rails
     the error message will include information on how to create a database:
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
index 95cd69d5ad..11a5eba464 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
@@ -46,7 +46,7 @@ module ActiveRecord
     # PostgreSQL-specific extensions to column definitions in a table.
     class PostgreSQLColumn < Column #:nodoc:
       attr_accessor :array
-      # Instantiates a new PostgreSQL column definition in a table.
+
       def initialize(name, default, oid_type, sql_type = nil, null = true)
         @oid_type = oid_type
         default_value     = self.class.extract_value_from_default(default)
@@ -62,6 +62,14 @@ module ActiveRecord
         @default_function = default if has_default_function?(default_value, default)
       end
 
+      def number?
+        !array && super
+      end
+
+      def text?
+        !array && super
+      end
+
       # :stopdoc:
       class << self
         include ConnectionAdapters::PostgreSQLColumn::Cast
diff --git a/activerecord/test/cases/adapters/postgresql/array_test.rb b/activerecord/test/cases/adapters/postgresql/array_test.rb
index 114d5b6cc6..b0870e2256 100644
--- a/activerecord/test/cases/adapters/postgresql/array_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/array_test.rb
@@ -26,6 +26,12 @@ class PostgresqlArrayTest < ActiveRecord::TestCase
   def test_column
     assert_equal :string, @column.type
     assert @column.array
+    assert_not @column.text?
+
+    ratings_column = PgArray.columns_hash['ratings']
+    assert_equal :integer, ratings_column.type
+    assert ratings_column.array
+    assert_not ratings_column.number?
   end
 
   def test_change_column_with_array
@@ -50,8 +56,6 @@ class PostgresqlArrayTest < ActiveRecord::TestCase
   end
 
   def test_type_cast_array
-    assert @column
-
     data = '{1,2,3}'
     oid_type  = @column.instance_variable_get('@oid_type').subtype
     # we are getting the instance variable in this test, but in the