Open a diff from %G blame without opening the commit? (File for current blame?)

[idbrii]

Currently, to open a commit from a blame I take advantage of how <CR> opens a :Gdiffsplit when the cursor is on the 'diff --git' line of a commit view. Mapping in ~/.vim/after/ftplugin/fugitiveblame.vim with:

nmap <buffer> dd <CR>?^diff<CR><CR>

However, is it possible to skip opening the commit? Sometimes our commits are huge and slow to open (binary files and bad merges, I can't prevent it). If I could :Gedit sha:file and then :Gdiff sha~, then that should work. But I don't know how to get file because the fugitiveblame file is a temp file.

Even worse, I actually always use :%G blame to skip the scrollbind and just view the blame contents so there isn't another window with the file.

Is there some way to get the filename for the current blame buffer?

[JoaoNevez]

git blame -L 42,42 path/to/file

[idbrii]

That opens a blame for a single line of the file but how do I jump from that to a split diff that introduced that line?

[tpope]

If you call FugitiveResult(bufnr('')) in the blame buffer, you'll get back a dictionary that contains among other things blame_file. This is the originally blamed file and doesn't account for rename detection.

[idbrii]

Thanks! That was a big help.

Also, I noticed that I didn't realize that each line may have the filepath in it too -- I guess only when there are renames!

Using nvim:

" ~/.vim/after/ftplugin/fugitiveblame.vim

" File diff that changed current line.
nnoremap <buffer> dd <Cmd>:lua require "idbrii.git".ReblameCurrentLine()<CR>

" ~/.vim/lua/idbrii/git.lua
local git = {}

function git.ReblameCurrentLine()
    local t = vim.fn.FugitiveResult(vim.fn.bufnr(''))
    if not next(t) then
        return
    end

    -- Metadata is concealed and wrapped in (parens).
    local dest_sha, file, line = vim.fn.getline('.'):match("^(%x+) (.-)%s+[^(]+ %b() (.*)")
    if not dest_sha then
        return
    end

    if not file:find("%a") then
        -- file is only present when there are renames.
        file = t.blame_file
    end

    -- Open new tab because it's much easier to return to blame.
    local fmt = "Gtabedit %s:%s"
    vim.fn.execute(fmt:format(dest_sha, file, dest_sha))
    vim.fn.execute("Gdiff !~")

    -- View the selected line.
    vim.cmd.wincmd"p"
    if dest_sha:len() > 0 then
        vim.fn.search("\\V".. line)
    end
    vim.cmd.normal{ "zz", bang = true }

    return true
end

return git