Provide a pre-completion-hook for features like fast return on cached paramaters

[idvorkin]

First Check

• I added a very descriptive title here.
• I used the GitHub search to find a similar question and didn't find it.
• I searched the Typer documentation, with the integrated search.
• I already searched in Google "How to X in Typer" and didn't find any information.
• I already read and followed all the tutorials in the docs and didn't find an answer.
• I already checked if it is not related to Typer but to Click.

Commit to Help

• I commit to help with one of those options 👆

Example Code

# Would be great if I could do something like this

from  typer.fast.precompletehook import is_completion, get_completion_data, do_completion

# top of file

# fast return if no changes
if is_completion():
   if no_changes_to_script():
      completion = read_completion_data_from_disk()
      return
 


# normal script
import typer
... 

def main():
    print("Hello World")


if __name__ == "__main__":
    if is_completion():
      completion = get_completion_data(main)
      save_completion_with_script_hash_to_disk(completion)
      do_completion(completion)

    typer.run(main)

Description

Typer takes ~ 500ms for autocomplete on my m1 macbook. Pythong can run in 50 ms.

Would be great if we could save the completion and return a cached copy. I'm confident :) this needs custom business logic, so will likely need to expose hooks to let developers customize.

I did something like this for another python script that reflects on typer commands before returning completion for another tool, using a cache gets me from 500ms => 50ms:

Look at y.py in this diff:

idvorkin/Settings@1ee830a#diff-d21acc80b353a7c602db52322ed4f6704b1d6a088176bd93f61af5e819a3489b

I was trying to grock how to do this, but seems pretty complex from reading: #951 (comment)

Operating System

macOS

Operating System Details

No response

Typer Version

Latest

Python Version

Latest

Additional Context

No response