Transformer weighting algorithm fails to determine transformer with higher priority

• User impact:

  High
• Log Output:

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  Root Exception stack trace:
  org.mule.api.registry.ResolverException: There are two transformers that are an exact match for input: "class org.apache.xerces.dom.DocumentImpl", output: "class java.lang.String". Transformers are: "FileToString(class org.mule.transport.file.transformers.FileToString)" and "_DomDocumentToString(class org.mule.module.xml.transformer.DomDocumentToXml)"
  at org.mule.registry.TypeBasedTransformerResolver.getNearestTransformerMatch(TypeBasedTransformerResolver.java:162)
  at org.mule.registry.TypeBasedTransformerResolver.resolve(TypeBasedTransformerResolver.java:88)
  at org.mule.registry.MuleRegistryHelper.resolveTransformer(MuleRegistryHelper.java:266)
      + 3 more (set debug level logging or '-Dmule.verbose.exceptions=true' for everything)
  

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  Root Exception stack trace: org.mule.api.registry.ResolverException: There are two transformers that are an exact match for input: "class org.apache.xerces.dom.DocumentImpl", output: "class java.lang.String". Transformers are: "FileToString(class org.mule.transport.file.transformers.FileToString)" and "_DomDocumentToString(class org.mule.module.xml.transformer.DomDocumentToXml)" at org.mule.registry.TypeBasedTransformerResolver.getNearestTransformerMatch(TypeBasedTransformerResolver.java:162) at org.mule.registry.TypeBasedTransformerResolver.resolve(TypeBasedTransformerResolver.java:88) at org.mule.registry.MuleRegistryHelper.resolveTransformer(MuleRegistryHelper.java:266)     + 3 more (set debug level logging or '-Dmule.verbose.exceptions=true' for everything)
• Similar Issues:

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The transformer weighting algorithm does not resolve the correct transformer in some situations.
Apparently, when a transformer's source data type implements an interface.

Example: when the attached config there are to transformers that match the transformation from DocumentImpl to String: FileToString and DomDocumentToXml.

These are the types matched by each transformer:

FileToString : DocumentImpl > CoreDocumentImpl > ParentNode > ChildNode > NodeImpl > Serializable
DomDocumentToXml : DocumentImpl > CoreDocumentImpl > Document

DomDocumentToXml matches a type that is near in the class hierarchy, however the algorithm determines that FileToString has higher priority weight.