Re: [PATCH] Support "core.excludesfile = ~/.gitignore"

Karl Chen [off-list ref] writes:

Another idea is to have a non-absolute path be interpreted
relative to the location of .gitconfig.

If we were to support relative paths, I think it would be useful and
consistent if a relative path found in ".git/config" is relative to the
work tree root, in "config" in a bare repository relative to the bare
repository, and in "$HOME/.gitconfig" relative to $HOME.  I am not sure
what a relative path in "/etc/gitconfig" should be relative to, though.

However, this has a technical difficulty.  When configuration values are
read, the code that knows what the value means does not in general know
which configuration file is being read from.

Below is a sample patch that works for me.  We could also use
getpwuid(getuid()) instead of getenv("HOME") to be consistent with
user_path() but this is simpler and arguably more likely what the
user wants when it matters.

It is quite likely that somebody would want you to interpret "~name/" if
you advertize that you support "~/", so you would need to call getpwuid()
eventually if you go down this path.  I wonder how this would affect
Windows folks.

What are the paths valued configuration variables other than excludesfile
that we would want to support?  There was a topic to allow mail-aliases
lookup for parameters given to the "--author" option today, and send-email
takes aliasfile configuration.  Because the latter is a script, we would
need a "--path" option to "git config" (the idea is similar to existing
"--bool" option) so that calling scripts can ask the same "magic"
performed to configuration variables' values before being reported.