handle scientific notation default values (#224)

* handle scientific notation default values
* fix CI issue

Author: FX-HAO

build/Dockerfile

@@ -4,7 +4,7 @@
 FROM cockroachdb/example-orms-builder:20200413-1918
 
 # Native dependencies for libxml-ruby and sqlite3.
-RUN apt-get update -y && apt-get install -y \
+RUN apt-get --allow-releaseinfo-change update -y && apt-get install -y \
   libxslt-dev \
   libxml2-dev \
   libsqlite3-dev \

lib/active_record/connection_adapters/cockroachdb_adapter.rb

@@ -352,7 +352,8 @@ def extract_value_from_default(default)
           super ||
             extract_escaped_string_from_default(default) ||
             extract_time_from_default(default) ||
-            extract_empty_array_from_default(default)
+            extract_empty_array_from_default(default) ||
+            extract_decimal_from_default(default)
         end
 
         # Both PostgreSQL and CockroachDB use C-style string escapes under the
@@ -403,6 +404,14 @@ def extract_empty_array_from_default(default)
           return "{}"
         end
 
+        # This method exists to extract the decimal defaults (e.g. scientific notation)
+        # that don't get parsed correctly
+        def extract_decimal_from_default(default)
+          Float(default).to_s
+        rescue
+          nil
+        end
+
         # override
         # This method makes a query to gather information about columns
         # in a table. It returns an array of arrays (one for each col) and

test/cases/defaults_test.rb

@@ -21,4 +21,25 @@ class DefaultExpressionTest < ActiveRecord::TestCase
       assert_match %r/t\.datetime\s+"modified_time_function",\s+default: -> { "now\(\)" }/, output
     end
   end
+
+  class DefaultNumbersTest < ActiveRecord::TestCase
+    class DefaultNumber < ActiveRecord::Base; end
+
+    setup do
+      @connection = ActiveRecord::Base.connection
+      @connection.create_table :default_numbers do |t|
+        t.decimal :decimal_number, precision: 32, scale: 16, default: 0
+      end
+    end
+
+    teardown do
+      @connection.drop_table :default_numbers, if_exists: true
+    end
+
+    def test_default_decimal_number_in_scientific_notation
+      record = DefaultNumber.new
+      assert_equal 0.0, record.decimal_number
+      assert_equal "0.0", record.decimal_number_before_type_cast
+    end
+  end
 end