Use String#to_i for integer/float, and Integer() for octal/binary/hex

* This represents a change in how we typecast values.  If the value
  does not match a format we know can be coerced into the object, then
  we skip typecasting and leave the value as-is.  If dm-validations is
  enabled, the value can be identified as invalid, but the original
  value is left alone by dm-core rather than turned into a nil.

lib/dm-core/property.rb

@@ -686,23 +686,12 @@ def typecast(value)
       begin
         # TODO: optimize this using a Hash lookup table
         if primitive == Integer
-          # The simplest possible implementation, i.e. value.to_i, is not
-          # desirable because "junk".to_i gives "0". We want nil instead,
-          # because this makes it clear that the typecast failed.
-          #
-          # After benchmarking, we preferred the current implementation over
-          # these two alternatives:
-          # * Integer(value) rescue nil
-          # * Integer(value_to_s =~ /(\d+)/ ? $1 : value_to_s) rescue nil
-
-          # DB: I've reverted this to Integer(value), since the behavior
-          # DB: of Integer(value) is NOT the same as value.to_i, for example:
-          # Integer("0x24") == 36
-          # "0x24".to_i == 0
-          begin
-            Integer(value)
-          rescue
-            value.to_s =~ /^(0x|0b|0\.)?0+$/ ? 0 : nil
+          # only typecast a String that looks like a number
+          case value.to_s
+            when /\A((?:0|[1-9]\d*)(?:\.\d+)?)\z/     then $1.to_i      # integer or float
+            when /\A(0(?:\d+|b[01]+|x[a-fA-F\d]+))\z/ then Integer($1)  # octal, binary or hex
+            else
+              value
           end
         elsif primitive == String     then value.to_s
         elsif primitive == TrueClass  then %w[ true 1 t ].include?(value.to_s.downcase)

spec/public/property_spec.rb

@@ -346,15 +346,16 @@ class ::Image
           it { Image.properties[:width].typecast(0.0).should == 0 }
           it { Image.properties[:width].typecast("0").should == 0 }
           it { Image.properties[:width].typecast("0.0").should == 0 }
+          it { Image.properties[:width].typecast("00").should == 0 }
+          it { Image.properties[:width].typecast("0b0").should == 0 }
           it { Image.properties[:width].typecast("0x0").should == 0 }
           it { Image.properties[:width].typecast(BigDecimal("0.0")).should == 0 }
           it { Image.properties[:width].typecast(Rational(0,1)).should == 0 }
         end
 
         describe "but value has non-digits and punctuation in it" do
-          it "returns result of property type's casting of nil" do
-            # nil.to_f => 0.0
-            Image.properties[:width].typecast("datamapper").should be_nil
+          it "returns value without typecasting" do
+            Image.properties[:width].typecast('datamapper').should == 'datamapper'
           end
         end
       end