cz commit with prepare-commit-msg hook

Description

cz commit is very good tool. If prepare-commit-msg hook calls cz commit, become easy to commit by many user.

Possible Solution

like cz check, writing pre-commit config

---
repos:
- hooks:
  - id: commitizen-prepare-commit-msg
    stages: [prepare-commit-msg]

and user type git comit, then prepare-commit-msg hook works and invokes cz commit.

Is this feature accepted as this product policy?

Additional context

I did a basic research. And I found that there are two issues.

• The current cz commit calls git. But in this case, git calls cz commit
• Git hook is started without standard input, so we can’t create commit message interactively

I made a test implementation to solve the problem by the following method

• When called from git, write the commit message to the file which is set by “–commit-msg-file” argument
• Open tty manualy and use as stdio.

but this change has sideffect.

tty is manually opened as io.FileIO. But prompt_toolkit (which used by questionary) assumes tty is opened as io.TextIOWrapper. As a workaround I added wrap class

class WrapStdin:
    def __init__(self):
        fd = os.open("/dev/tty", os.O_RDWR | os.O_NOCTTY)
        tty = open(fd, "wb+", buffering=0)
        self.tty = tty

    def __getattr__(self, key):
        if key == "encoding":
            return "UTF-8"
        return getattr(self.tty, key)

    def __del__(self):
        self.tty.close()

All patch code is here. https://github.com/saygox/commitizen/commit/033159d08e240c493b5fa36d67e870e3b443d4d6

[Lee-W]

@mrlubos Thanks for the summary! It’s super helpful. I’ll take a deeper look and see how I can fix it when I have time 💪

[woile]

Quite interesting indeed, please open a PR so we can discuss it there!