mapping compare: ignore string fields converted to text/keyword fields

Elasticsearch 5 will automatically convert string mapping types to be
text or keyword types. We want to support both ES 2.4 and 5, so keep the
declared mappings using the string type. When we check this against what
is deployed, ignore the difference if a string is converted to text or
keyword.

Author: haarg

lib/MetaCPAN/Script/Mapping.pm

@@ -688,7 +688,24 @@ sub _compare_mapping {
                         }
                     }
                     else {    # Scalar Value
-                        if ( $deploy_value ne $model_value ) {
+                        if (
+                               $sfield eq 'type'
+                            && $model_value eq 'string'
+                            && (   $deploy_value eq 'text'
+                                || $deploy_value eq 'keyword' )
+                            )
+                        {
+                            # ES5 automatically converts string types to text
+                            # or keyword. once we upgrade to ES5 and update
+                            # our mappings, this special case can be removed.
+                        }
+                        elsif ($sfield eq 'index'
+                            && $model_value eq 'no'
+                            && $deploy_value eq 'false' )
+                        {
+                            # another ES5 string automatic conversion
+                        }
+                        elsif ( $deploy_value ne $model_value ) {
                             log_error {
                                 'Mismatch field: '
                                     . $sname . '.'