Empty MorphAnalysis Hash differs from Token.morph.key

[thjbdvlt]

Hello,

I've trained a Morphologizer and i saw that empty MorphAnalysis ("") actually have the hash value of "_". Is it by design? Because the documentation doesn't mention this.

key int | The hash of the features string.

for i in doc:
    nlp.vocab.strings[i.morph.key] == str(i.morph)
False
False
False
True
False
True
True
False

As i use the hash values in a lookup for something, it produced KeyError.

How to reproduce the behaviour

Your Environment

• Operating System: Linux (Debian 12)
• Python Version Used: 3.11
• spaCy Version Used: 3.7.3 (i will train my Morphologizer soon on 3.8.3 to see if that change)
• Environment Information: