Re: [PATCH] repository: fix free problem with repo_clear(the_repository)

From: Duy Nguyen <pclouds@gmail.com>
Date: May 10, 2018, 06:18 UTC
Message-ID: <CACsJy8CosHdk3DA46aNM3v5d4wnmLumv+6MdJMY=WfVtKqZ8LA@mail.gmail.com>
In-Reply-To: <CACsJy8AdJcQpiGrR3p6xfuqU0=qoP3=StgbWRNCkdfka6di+5w@mail.gmail.com>

On Wed, May 9, 2018 at 8:00 PM, Duy Nguyen <pclouds@gmail.com> wrote:

Show 9 quoted lines

> discard_index(repo->index);
> if (repo->index != &the_index)
>         FREE_AND_NULL(repo->index);
>
>> What is your use case of repo_clear(the_repository)?
>
> No actual use case right now. See [1] for the code that triggered
> this. I do want to free some memory in pack-objects and repo_clear()
> _might_ be the one. I'm not sure yet.

Another use case for repo_clear(the_repository) is "git worktree move". Part of the reason I did not support moving the main repository with that command is because I wanted to shut down every access to $MAIN_WORK_TREE/.git before moving $MAIN_WORK_TREE. It's probably not a problem for linux/mac platforms to move files (on the same file system [1]) with file descriptors still open, but I'm pretty sure it won't work on Windows. If repo_clear() does its job well, I should be able to safely move $GIT_WORK_TREE after that.

[1] if we move across file systems then another set of problems arise: if file descriptors remain open, writing to those will not affect the new copies in the target. We do not support moving across filesystems yet, but we should not shut that door now.

-- 
Duy