Document mapping doesn't accept any name but 'doc'

I tried to use the new 6.2 release and found that the following code crashes:

from elasticsearch_dsl import Document, Mapping

class MyDoc(Document):
    class Meta:
        mapping = Mapping('a')

With the following trace:

/lib/python3.6/site-packages/elasticsearch_dsl/document.py in __new__(cls, name, bases, attrs)
     30         new_cls = super(IndexMeta, cls).__new__(cls, name, bases, attrs)
     31         new_cls._index = cls.construct_index(index_opts, bases)
---> 32         new_cls._index.document(new_cls)
     33         return new_cls
     34

/lib/python3.6/site-packages/elasticsearch_dsl/index.py in document(self, document)
    121             raise IllegalOperation(
    122                 'Index object cannot have multiple types, %s already set, '
--> 123                 'trying to assign %s.' % (self._mapping.doc_type, name))
    124         self._doc_types.append(document)
    125         # TODO: do this at save time to allow Document to be modified after

IllegalOperation: Index object cannot have multiple types, doc already set, trying to assign a.

I tried to add doc_type='a' to the Meta class, but it didn’t help. As far as I have tried, there’s absolutely no way to have a mapping which is not named 'doc'. This is also incompatible with existing indexes.

[honzakral]

Thank you all for your patience, I just pushed a fix that should make the part in class Index optional, so just defining a class Meta: doc_type = "a" should be enough.

I also cleaned up a lot of faulty logic when it came to Index handling. If you could test the current master (69f5ca2dc7657c26a19f11d75b7c2080afcfcdd6) I would be most grateful! After it has been tested I will release it as 6.3.0

[jason-huling]

@rafaelcaricio, turns out I should have troubleshot a little longer 😄 …

The following worked for me to avoid elasticsearch_dsl.exceptions.IllegalOperation:

class MyDoc(Document):
    class Index:
        doc_type = "a"
        
    class Meta:
        doc_type = "a"

I noticed that the following gave the error a already set, trying to assign doc

class MyDoc(Document):
    class Index:
        doc_type = "a"

And this gave the same error but reversed doc already set, trying to assign a

class MyDoc(Document):
    class Meta:
        doc_type = "a"

So setting doc_type in both Index and Meta is required to align them and prevent the error.

@HonzaKral do you know if this behavior is intentional?