Issue with Type Hints for `fields` Parameter in Elasticsearch Python Client about elasticsearch-py

[pquentin]

Hey @mpaluch92, thank you for your detailed bug report. You are right that passing a list of string is supported and that the type annotation is wrong. In fact, this was initially reported by @JannKleen in #2347, and I forgot to reopen the issue when I realized my fix had to be reverted.

The rest of this comment gives more technical details, but you can ignore them. I'll close this issue when I fix the bug.

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The code that is wrong is generated from https://github.com/elastic/elasticsearch-specification. For mvt_search and the deprecated knn_search API, fields is typed as Fields, which boils down to a string or an array or strings. However, this is wrong, because those API also accept objects that define field but also format. For this reason, in the _search API, fields is typed as Array<FieldAndFormat>, with FieldAndFormat being a class. This seemed wrong, so I opened a pull request to change the type to Array<Field | FieldAndFormat>, but I had to revert it because the bug was in the code generator that was not taking into account shortcut_property instead to allow strings, not only mappings.

Long story short, I need to fix the (private) Python code generator to take into account shortcut_property and fix the type hints. In the meantime, you may need # pyright: ignore or # mypy: ignore annotations, sorry.