Add diff gutter

runtime/plugins/diff/diff.lua

@@ -0,0 +1,20 @@
+VERSION = "1.0.0"
+
+local os = import("os")
+local filepath = import("path/filepath")
+local shell = import("micro/shell")
+
+function onBufferOpen(buf)
+	if (not buf.Type.Scratch) and (buf.Path ~= "") then
+		-- check that file exists
+		local _, err = os.Stat(buf.AbsPath)
+		if err == nil then
+			local dirName, fileName = filepath.Split(buf.AbsPath)
+			local diffBase, err = shell.ExecCommand("git", "-C", dirName, "show", "HEAD:./" .. fileName)
+			if err ~= nil then
+				diffBase = buf:Bytes()
+			end
+			buf:SetDiffBase(diffBase)
+		end
+	end
+end