(WIP) Addition of validate legacy function

Author: Helen Campbell

lib/puppet/functions/validate_legacy.rb

@@ -0,0 +1,54 @@
+Puppet::Functions.create_function(:validate_legacy, Puppet::Functions::InternalFunction) do
+  dispatch :validate_legacy do
+    param 'Type', :target_type
+    param 'String', :previous_validation #Needs to be the name of the function previously used
+    param 'NotUndef', :value #Really not sure what all this could be
+    optional_param 'Any', :args # /need special stuff for any number of args herei
+  end
+  dispatch :validate_legacy_s do
+    scope_param
+    param 'String', :type_string
+    param 'String', :previous_validation
+    param 'NotUndef', :value
+    optional_param 'Any', :args
+  end
+
+  def validate_legacy_s(scope, type_string, *args)
+    t = Puppet::Pops::Types::TypeParser.new.parse(type_string, scope)
+    validate_legacy(t, *args)
+  end
+
+  def validate_legacy(target_type, previous_validation, value, *prev_args)
+    if assert_type(target_type, value)
+      if previous_validation(previous_validation, value, *prev_args)
+        # silently passes
+      else
+        # succeed with warning "Accepting previously invalid value for target_type"
+        warning("Accepting previously invalid value for target_type '#{target_type}'")
+      end
+    else
+      inferred_type = Puppet::Pops::Types::TypeCalculator.infer_set(value)
+      error_msg = Puppet::Pops::Types::TypeMismatchDescriber.new.describe_mismatch('@@validate_legacy', target_type, inferred_type)
+      if previous_validation(previous_validation, value, *prev_args)
+        # succeed with deprecation warning (use new error message)
+        call_function('warning', error_msg)
+      else
+        # fail with new error message
+        call_function('fail', error_msg)
+      end
+    end
+  end
+
+  def previous_validation(previous_validation, value, *prev_args)
+    # Call the previous validation function and catch any errors
+    begin
+      call_function(previous_validation, value, *prev_args)
+    rescue Puppet::ParseError
+      false
+    end
+  end
+
+  def assert_type(type, value)
+    Puppet::Pops::Types::TypeCalculator.instance?(type, value)
+  end
+end