Re: [PATCH v6 1/1] config: add conditional include

> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> ---
>  Documentation/config.txt  | 61 +++++++++++++++++++++++++++++
>  config.c                  | 97 +++++++++++++++++++++++++++++++++++++++++++++++
>  t/t1305-config-include.sh | 56 +++++++++++++++++++++++++++
>  3 files changed, 214 insertions(+)
> 
> diff --git a/Documentation/config.txt b/Documentation/config.txt
> index 015346c417..6c0cd2a273 100644
> --- a/Documentation/config.txt
> +++ b/Documentation/config.txt
> @@ -91,6 +91,56 @@ found at the location of the include directive. If the value of the
>  relative to the configuration file in which the include directive was
>  found.  See below for examples.
>  
> +Conditional includes
> +~~~~~~~~~~~~~~~~~~~~
> +
> +You can include one config file from another conditionally by setting
> +a `includeIf.<condition>.path` variable to the name of the file to be
> +included. The variable's value is treated the same way as `include.path`.
> +
> +The condition starts with a keyword followed by a colon and some data
> +whose format and meaning depends on the keyword. Supported keywords
> +are:
> +
> +`gitdir`::
> +
> +	The data that follows the keyword `gitdir:` is used as a glob
> +	pattern. If the location of the .git directory match the
> +	pattern, the include condition is met.
> ++
> +The .git location which may be auto-discovered, or come from
> +`$GIT_DIR` environment variable. If the repository auto discovered via
> +a .git file (e.g. from submodules, or a linked worktree), the .git
> +location would be the final location, not where the .git file is.
> ++
> +The pattern can contain standard globbing wildcards and two additional
> +ones, `**/` and `/**`, that can match multiple path components. Please
> +refer to linkgit:gitignore[5] for details. For convenience:
> +
> + * If the pattern starts with `~/`, `~` will be substituted with the
> +   content of the environment variable `HOME`.
> +
> + * If the pattern starts with `./`, it is replaced with the directory
> +   containing the current config file.
> +
> + * If the pattern does not start with either `~/`, `./` or `/`, `**/`
> +   will be automatically prepended. For example, the pattern `foo/bar`
> +   becomes `**/foo/bar` and would match `/any/path/to/foo/bar`.
> +
> + * If the pattern ends with `/`, `**` will be automatically added. For
> +   example, the pattern `foo/` becomes `foo/**`. In other words, it
> +   matches "foo" and everything inside, recursively.
> +
> +`gitdir/i`::
> +	This is the same as `gitdir` except that matching is done
> +	case-insensitively (e.g. on case-insensitive file sytems)
> +
> +A few more notes on matching with `gitdir` and `gitdir/i`:
> +
> + * Symlinks in `$GIT_DIR` are not resolved before matching.
> +
> + * Note that "../" is not special and will match literally, which is
> +   unlikely what you want.
>  
>  Example
>  ~~~~~~~
> @@ -119,6 +169,17 @@ Example
>  		path = foo ; expand "foo" relative to the current file
>  		path = ~/foo ; expand "foo" in your `$HOME` directory
>  
> +	; include if $GIT_DIR is /path/to/foo/.git
> +	[include-if "gitdir:/path/to/foo/.git"]