mezzio / mezzio-hal

Bug Report

Q	A
Version(s)	2.3.1

Summary

This is a union of Foo and Tab in a JSONSchema resource:

{
  "components": {
    "SomeResource": {
      "oneOf": [
        {"$ref": "#/components/Foo"},
        {"$ref": "#/components/Tab"}
      ]
    },
    "Foo": {
      "type": "object",
      "required": ["bar"],
      "properties": {
        "bar": {"type": "string"}
      }
    },
    "Tab": {
      "type": "object",
      "required": ["taz"],
      "properties": {
        "taz": {"type": "string"}
      }
    }
  }
}

In practice, when rendering a list<SomeResource>, you will get an array of JSON objects with different properties:

[
  {"bar": "haha"},
  {"taz": "hehe"},
  {"bar": "hihi"}
]

Current behavior

HalResource#__construct() does some pretty aggressive validation of its JSON contents, specifically on $embedded data:

mezzio-hal/src/HalResource.php

Lines 512 to 529 in 29f006b

    
               /** 
        
                * @throws InvalidArgumentException If $a and $b are not structurally equivalent. 
        
                */ 
        
               private function compareResources(self $a, self $b, string $name, string $context): bool 
        
               { 
        
                   $structureA = array_keys($a->getElements()); 
        
                   $structureB = array_keys($b->getElements()); 
        
                   sort($structureA); 
        
                   sort($structureB); 
        
                   if ($structureA !== $structureB) { 
        
                       throw new InvalidArgumentException(sprintf( 
        
                           '%s detected structurally inequivalent resources for element %s', 
        
                           $context, 
        
                           $name 
        
                       )); 
        
                   } 
        
                   return true; 
        
               }

This precludes usage of well-documented resources of different types.

How to reproduce

configure a resource for class Foo { public string $bar = 'baz'; }
configure a resource for class Tab { public string $taz = 'tar'; }
render a (pseudo-code) new HalResource(..., ..., [new Foo(), new Tab()]) - it will crash due to Foo and Tab not sharing same properties

Expected behavior

A HalResource can be instantiated with $embedded data of different types: