Repository scoped configuration

[smackesey]

When working on multiple projects within the same Vim instance, gitsigns "base"-configuration functionality is not ideal, because there is no (documented) way to set the base separately for different projects. For example, suppose I am working on feature branches on project1 and project2. project1 uses main and project2 uses master for the central branch. I want to check the status of my feature branch against main in project1, so I run require('gitsigns').reset_base('main', true).

This is great for project1, but now the entire file content in project2 is treated as new, because the nonexistent branch main has been set as the base for project2.

Describe the solution you'd like
Allow setting cwd (i.e. project/workspace)-scoped base:

require('gitsigns').change_base('main', 'cwd')  # update for project
require('gitsigns').change_base('main, 'global')  # update globally

You could preserve backward compatibility by treating any truthy value that is not 'cwd' as equivalent to 'global'.

Describe alternatives you've considered
A hack where I store the cwd-scoped base in an external data structure and use autocmds to set the buffer base from this structure. Undesirable.

[lewis6991]

I think instead of cwd scoped, we want repo scoped, but either way this would be a useful feature that I find myself wanting too.