Re: [PATCH/RFC 3/4] config: read global scope via config_sequence

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

"Delilah Ashley Wu via GitGitGadget" <gitgitgadget@gmail.com>
writes:

> From: Delilah Ashley Wu <delilahwu@microsoft.com>
>
> The output of `git config list --global` should include both the home
> (`$HOME/.gitconfig`) and XDG (`$XDG_CONFIG_HOME/git/config`) configs,
> but it only reads from the former.

", but" -> "to match the information given by the command without
--global, but".

> This patch introduces a regression. If both global config files are
> unreadable, then `git config list --global` should exit non-zero. This
> is no longer the case, so mark the corresponding test as a "TODO known
> breakage" and address the issue in the next patch, config: keep bailing
> on unreadable global files.

That is rather unfortunate, as we do try hard to avoid deliberate
regressions in our history.  The reason why this step cannot be done
without first introducing a regression is...?

If the reason is "it would make a single patch too big", perhaps we
can do it in two steps, one preliminary "git_config_sequence() learns
an extra barf-if-no-input parameter that causes it to return error if
no files in the specified sequence exists" step, followed by this
change that starts using git_config_sequence() to handle "--global",
which uses that new flag to ensure that there won't be a regression?

>  	if (opts->use_global_config) {
> +		/*
> +		 * Since global config is sourced from more than one location,
> +		 * use `config.c#do_git_config_sequence()` with `opts->options`
> +		 * to read it. However, writing global config should point to a
> +		 * single destination, set in `opts->source.file`.
> +		 */
> +		opts->options.ignore_repo = 1;
> +		opts->options.ignore_cmdline= 1;
> +		opts->options.ignore_worktree = 1;
> +		opts->options.ignore_system = 1;
> +		opts->source.scope = CONFIG_SCOPE_GLOBAL;

Very nicely done.

Thanks.