Re: [PATCH v5 03/30] fsmonitor: config settings are repository-specific

> From: Jeff Hostetler <jeffhost@microsoft.com>
>
> Move fsmonitor config settings to a new and opaque
> `struct fsmonitor_settings` structure.  Add a lazily-loaded pointer
> to this into `struct repo_settings`
>
> Create an `enum fsmonitor_mode` type in `struct fsmonitor_settings` to
> represent the state of fsmonitor.  This lets us represent which, if
> any, fsmonitor provider (hook or IPC) is enabled.
>
> Create `fsm_settings__get_*()` getters to lazily look up fsmonitor-
> related config settings.
>
> Get rid of the `core_fsmonitor` global variable.  Move the code to
> lookup the existing `core.fsmonitor` config value into the fsmonitor
> settings.
>
> Create a hook pathname variable in `struct fsmonitor-settings` and
> only set it when in hook mode.
>
> Extend the definition of `core.fsmonitor` to be either a boolean
> or a hook pathname.  When true, the builtin FSMonitor is used.
> When false or unset, no FSMonitor (neither builtin nor hook) is
> used.
>
> The existing `core_fsmonitor` global variable was used to store the
> pathname to the fsmonitor hook *and* it was used as a boolean to see
> if fsmonitor was enabled.  This dual usage and global visibility leads
> to confusion when we add the IPC-based provider.  So lets hide the
> details in fsmonitor-settings.c and let it decide which provider to
> use in the case of multiple settings.  This avoids cluttering up
> repo-settings.c with these private details.
>
> A future commit in builtin-fsmonitor series will add the ability to
> disqualify worktrees for various reasons, such as being mounted from a
> remote volume, where fsmonitor should not be started.  Having the
> config settings hidden in fsmonitor-settings.c allows such worktree
> restrictions to override the config values used.

> diff --git a/fsmonitor.h b/fsmonitor.h
> index f20d72631d7..f9201411aa7 100644
> --- a/fsmonitor.h
> +++ b/fsmonitor.h
> @@ -3,6 +3,7 @@
>
>  #include "cache.h"
>  #include "dir.h"
> +#include "fsmonitor-settings.h"
>
>  extern struct trace_key trace_fsmonitor;
>
> @@ -57,7 +58,11 @@ int fsmonitor_is_trivial_response(const struct strbuf *query_result);
>   */
>  static inline int is_fsmonitor_refreshed(const struct index_state *istate)
>  {
> -	return !core_fsmonitor || istate->fsmonitor_has_run_once;
> +	struct repository *r = istate->repo ? istate->repo : the_repository;