Re: [PATCH] gdb: add .pre-commit-config.yaml

[Simon Marchi <simon.marchi@efficios.com>]

On 3/20/24 09:44, Andrew Burgess wrote:
> Simon Marchi <simon.marchi@efficios.com> writes:
> 
>> [I'm CCing the binutils list because this patch adds a file at the
>>  top-level, but it only concerns gdb for now.  But if you are want to use
>>  pre-commit for some things in binutils too, you are welcome to use that
>>  file for your needs.]
>>
>> Add a pre-commit [1] config file, with a single hook to run black
>> whenever a Python file is modified.  We can always add more hooks if we
>> find some that are useful.
>>
>> Using pre-commit to run hooks is opt-in, as in it's not mandatory at all
>> for development, but it can be useful to run some checks that are easy
>> to forget (like running black).  The hooks run locally on the
>> developer's machine when doing `git commit` (although they can also be
>> configured to run at other stages of the git workflow).
>>
>> Follow these instructions to install the hooks in your local development
>> git repository:
>>
>>  - Install pre-commit the way you prefer.  It can be using your OS
>>    package manager if it has a recent enough version, or using `pip
>>    install pre-commit`.
>>  - Go to the binutils-gdb repository and run `pre-commit install`.
>>
>> This installs a git hook at `.git/hooks/pre-commit`.
>>
>> Now, whenever you modify and try to commit a Python file, pre-commit
>> will run black on it.  For instance, if I try to insert something
>> misformatted, I get this when doing `git commit`:
>>
>>     $ git commit
>>     black....................................................................Failed
>>     - hook id: black
>>     - files were modified by this hook
>>
>>     reformatted gdb/python/lib/gdb/dap/breakpoint.py
>>
>>     All done! ✨ 🍰 ✨
>>     1 file reformatted.
>>
>> At this point, black has already reformatted the files in place, so the
>> changes that fix the formatting are ready to add and commit.  black is
>> only ran on files modified in the commit.
>>
>> The hook defines a black version, which is downloaded at `pre-commit
>> install` time.  pre-commit manages its own env at
>> `$HOME/.cache/pre-commit/<some-hash>`, so it won't use the version of
>> black you have installed already.  This may help ensure that
>> contributors use the right black version.
> 
> This sounds great.  I got a recent commit wrong because the version of
> black was rolled forward and I'd not updated locally, so this would
> really help.
> 
> +1 from me for making this a thing.

Thanks!  Given that I only got positive feedback and this file won't
hurt anybody who doesn't care about it, I went ahead and pushed the
patch.  I added Acked-Bys for all those who provided feedback.

I'll now go ahead and updated the wiki.

Simon