Git prompt for Clink

git-prompt.lua

function trim(str)
	return (str:gsub("^%s*(.-)%s*$", "%1"))
end

function exec(command)
	local file = io.popen(command .. ' 2>nul', 'r')
	local output = trim(file:read('*all'))
	local rc = {file:close()}

	local exit_code = rc[3]

	return output, exit_code
end

function isEmpty(str)
	return (trim(str) == "")
end

function getGitBranch()
	local branchName = ""

	-- Check if the current directory is in a Git repository
	local output, exit_code = exec("git rev-parse")
	if (not (exit_code == 0)) or (not isEmpty(output)) then
		return ""
	end

	-- Is a Git repository, but has no HEAD pointer or tags
	-- Either it is an empty  Git repo or something went wrong
	local headInfo, exit_code = exec("git show-ref --head --tags")
	if (not (exit_code == 0)) or isEmpty(headInfo) then
		return ""
	end

	-- Get the short symbolic ref for HEAD
	branchName, exit_code = exec("git rev-parse --abbrev-ref HEAD")

	-- Early exit
	if not (exit_code == 0) then
		return ""
	end

	-- If HEAD isn't a symbolic ref, get the short SHA for the latest commit
	if isEmpty(branchName) or branchName == "HEAD" then
		branchName, exit_code = exec("git rev-parse --short HEAD")
		if exit_code == 0 then
			return branchName
		else
			return ""
		end
	end

	-- Otherwise, just give up.
	return branchName
end


function promptGit()
	local branchName = getGitBranch()

	if not isEmpty(branchName) then
		clink.prompt.value = clink.prompt.value .. " (" .. branchName .. ") "
	end

	return false
end

clink.prompt.register_filter(promptGit, 1)