Subject: Re: [PATCH] fsmonitor: only enable it in non-bare repositories

From: Ævar Arnfjörð Bjarmason <[email-masked]>
Date: Mon, 03 May 2021 15:58:48 +0200

On Thu, Apr 29 2021, Johannes Schindelin via GitGitGadget wrote:

> From: Johannes Schindelin <[email-masked]>
>
> The entire point of the FSMonitor is to monitor the worktree changes in
> a more efficient manner than `lstat()`ing all worktree files every time
> we refresh the index.
>
> But if there is no worktree, FSMonitor has nothing to monitor.
>
> So let's ignore if an FSMonitor is configured (e.g. in `~/.gitconfig`)
> and we're running in a repository without worktree.
>
> Signed-off-by: Johannes Schindelin <[email-masked]>
> ---
>     fsmonitor: only enable it in non-bare repositories
>     
>     Since I released Git for Windows v2.31.0, with brief interruption of two
>     weeks, I enabled the built-in FSMonitor via my user config, and today
>     was the first time I did anything in a bare repository. I was somewhat
>     surprised that FSMonitor gave me trouble there, as the FSMonitor does
>     not even make sense there...
>     
>     This patch applies on top of jh/rfc-builtin-fsmonitor (not because it
>     fixes a problem in the built-in FSMonitor, the bug existed for a long,
>     long time before those patches, but because it would otherwise cause
>     merge conflicts with that patch series).
>
> Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-942%2Fdscho%2Fbare-repositories-need-no-fsmonitor-v1
> Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-942/dscho/bare-repositories-need-no-fsmonitor-v1
> Pull-Request: https://github.com/gitgitgadget/git/pull/942
>
>  config.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/config.c b/config.c
> index 53e7dedc60de..fc5e744d81ca 100644
> --- a/config.c
> +++ b/config.c
> @@ -2515,6 +2515,12 @@ int git_config_get_max_percent_split_change(void)
>  
>  int repo_config_get_fsmonitor(struct repository *r)
>  {
> +	if (!r->worktree) {
> +		/* FSMonitor makes no sense in bare repositories */
> +		core_fsmonitor = 0;
> +		return 1;
> +	}
> +
>  	if (r->settings.use_builtin_fsmonitor > 0) {
>  		core_fsmonitor = "(built-in daemon)";
>  		return 1;
>
> base-commit: 14d50074ff19e68e7a8d718b22d138882087bbc9

This is surely a correct fix for now, but wouldn't it in the future also
be useful to run it in bare repositories e.g. to be able cache lookups
for non-existing loose objects?