Re: [RFC GSoC PATCH] environment: move core.trustctime to repo_settings

[Junio C Hamano <gitster@pobox.com>]

Ayush Jha <kumarayushjha123@gmail.com> writes:

> The core.trustctime configuration variable is currently stored as a global in environment.c. This prevents it from being repository-specific, which is problematic when multiple repository instances are used within the same process.
>
> This change continues the effort to move global configuration into struct repo_settings, as discussed in
> <20260208062949.596-1-kumarayushjha123@gmail.com>.
>
> Move trust_ctime into struct repo_settings so that it is associated with a repository instance.
>
> Add repo_settings_get_trust_ctime() to lazily read the
> core.trustctime configuration value, defaulting to true.
>
> Update statinfo.c to use the new accessor instead of the global variable.
>
> Signed-off-by: Ayush Jha <kumarayushjha123@gmail.com>
> ---
>  environment.c   | 5 -----
>  environment.h   | 1 -
>  repo-settings.c | 7 +++++++
>  repo-settings.h | 8 ++++++++
>  statinfo.c      | 4 ++--
>  5 files changed, 17 insertions(+), 8 deletions(-)

Doesn't this regress end-user experience when the configuration
variable is misspelled, e.g. "[core] trustctime = bad"?  We used to
run git_config_bool() from git_config(git_default_condfig) fairly
early in the program, and would have died before doing anythihng to
give the user a chance to fix the configuration files before going
forward.

Now we will run deep into codepath and would not notice the
misconfigured core.trustctime until the code happens to ask to
compare the filesystem stat data and in-core index stat data.

I think this is a recurring theme, e.g.

https://lore.kernel.org/git/32fceddc-c867-4a47-bde8-c873279edbc1@gmail.com/
https://lore.kernel.org/git/a881499d-e236-4f8e-a217-b6bce69e3e3c@gmail.com/

That other topic Olamide has been working on seems to have settled
*not* to lazily load into repo_settings to avoid the problem.
Instead it reads and parses at the same places in the code path as
before, but into a repo_config_values structure that is associated
with the repository in question (which typically is the_repository).