fix paths in errors

see the examples in https://json-schema.org/draft/2019-09/json-schema-core.html#rfc.section.10.4.2
but also see json-schema-org/json-schema-spec#937

- instance_location and keyword_location will always be json pointers
- absolute_keyword_location will always be an absolute URI or URI reference, when defined

Luckily the published schema at https://json-schema.org/draft/2019-09/output/schema
will still validate our output, because a bare json pointer looks like a uri
reference.

Author: karenetheridge

lib/JSON/Schema/Draft201909.pm

@@ -72,7 +72,7 @@ sub evaluate {
     short_circuit => $self->short_circuit,
     data_path => '',
     traversed_schema_path => '',  # the accumulated path up to the last $ref traversal
-    absolute_schema_path => '',   # the absolute path of the last traversed $ref
+    absolute_schema_uri => undef, # the absolute path of the last traversed $ref; always a Mojo::URL
     schema_path => '',            # the rest of the path, since the last traversed $ref
     errors => [],
   };
@@ -166,11 +166,11 @@ sub _eval_keyword_ref {
 
   # for now, the base_uri of the schema is always '' (yes I know this is not an absolute uri)
   # TODO: we need to track the base_uri of the schema resource that we are referencing.
-  # absolute_schema_path may not look anything like the contents of the $ref keyword.
+  # absolute_schema_uri may not look anything like the contents of the $ref keyword.
   return $self->_eval($data, $subschema,
     +{ %$state,
       traversed_schema_path => $state->{traversed_schema_path}.$state->{schema_path}.'/$ref',
-      absolute_schema_path => $url->to_string,
+      absolute_schema_uri => $url,
       schema_path => '',
     });
 }
@@ -853,8 +853,10 @@ sub E {
   push @{$state->{errors}}, JSON::Schema::Draft201909::Error->new(
     instance_location => $state->{data_path},
     keyword_location => $state->{traversed_schema_path}.$state->{schema_path}.$suffix,
-    !$state->{absolute_schema_path} ? ()
-      : ( absolute_keyword_location => $state->{absolute_schema_path}.$state->{schema_path}.$suffix ),
+    !$state->{absolute_schema_uri} ? () : ( absolute_keyword_location => do {
+      my $abs = $state->{absolute_schema_uri}->clone;
+      $abs->fragment($abs->fragment.$state->{schema_path}.$suffix);
+    } ),
     error => @args ? sprintf($error_string, @args) : $error_string,
   );
 

lib/JSON/Schema/Draft201909/Error.pm

@@ -15,9 +15,18 @@ use namespace::clean;
 has [qw(
   instance_location
   keyword_location
-  absolute_keyword_location
   error
-)] => ( is => 'ro', isa => Str );
+)] => (
+  is => 'ro',
+  isa => Str,
+  required => 1,
+);
+
+has absolute_keyword_location => (
+  is => 'ro',
+  isa => Str, # always a uri (absolute uri or uri reference)
+  coerce => sub { "$_[0]" },
+);
 
 sub TO_JSON {
   my $self = shift;