Re: [PATCH] builtins: reset startup_info->have_run_setup_gitdir when unsetting up repository

From: Jonathan Nieder <jrnieder@gmail.com>
Date: Mar 27, 2010, 22:38 UTC
Message-ID: <20100327223813.GA5809@progeny.tock>
In-Reply-To: <1269681184-1992-2-git-send-email-pclouds@gmail.com>

Hi again,

Nguyễn Thái Ngọc Duy wrote:

> While at it, also reset repository_format_version to zero. When
> omitted, the format should be understood as the last supported
> version, i.e. zero. This is probably only used by "git init" or "git
> clone".

[...]

>  	/* Initialized in check_repository_format_version() */
> -	repository_format_version = 0xFF;
> +	repository_format_version = 0;

Good change, but wrong justification in my opinion.

v0.99.9l^2~54 (init-db: check template and repository format., 2005-11-25) taught ‘git init-db’ to make sure that

  repository_format_version <= GIT_REPO_VERSION

before initializing a new repository. repository_format_version was being explicitly initialized globally to 0 at the time, presumably to ensure tests like this always succeed when no repository format version is declared (or in other words, the repository format for repositories initialized before git v0.99.9l^2~56 is zero by convention). As a happy side effect, that default takes care of the “no pre-existing repository” case here.

The explicit initialization was removed in commit v1.4.3-rc1~230 (remove unnecessary initializations, 2006-08-15), since according to ANSI C it is redundant.

So I think the convention is not “if in doubt, the repository has version GIT_REPO_VERSION” but “if the repository lacks a core.repositoryversion setting, it must be really old”.

Jonathan