refactor(git): load git:// URI buffers via BufReadCmd

lua/git/sidebar.lua

@@ -485,14 +485,14 @@ end
 local function head_pane(worktree, path)
     return {
         buf = diff.git_show_buf(worktree, "HEAD", path),
-        name = "git://HEAD/" .. path,
+        name = "git://HEAD//" .. path,
     }
 end
 
 ---@param path string
 ---@return ow.Git.DiffSide
 local function head_empty_pane(path)
-    return { buf = diff.empty_buf(), name = "git://HEAD/" .. path }
+    return { buf = diff.empty_buf(), name = "git://HEAD//" .. path }
 end
 
 ---@param worktree string
@@ -508,7 +508,7 @@ end
 ---@param path string
 ---@return ow.Git.DiffSide
 local function worktree_empty_pane(path)
-    return { buf = diff.empty_buf(), name = "git://worktree/" .. path }
+    return { buf = diff.empty_buf(), name = "git://worktree//" .. path }
 end
 
 ---@param s ow.Git.SidebarState
@@ -520,9 +520,9 @@ local function index_pane(s, entry)
         or (entry.section == "Staged" and entry.x == "D")
     )
     return {
-        buf = in_index and diff.git_show_buf(s.worktree, "", entry.path, true)
+        buf = in_index and diff.git_show_buf(s.worktree, "index", entry.path)
             or diff.empty_buf(),
-        name = "git://index/" .. entry.path,
+        name = "git://index//" .. entry.path,
     }
 end
 
@@ -727,15 +727,6 @@ local function show_diff(s, entry, focus_left)
             diff.set_buf_name_and_filetype(side.buf, side.name)
         end
     end
-    -- Synthetic index/HEAD buffers never run BufRead, so modeline-only
-    -- filetypes aren't detected. Copy from the side that did resolve.
-    local left_ft = vim.bo[pair.left.buf].filetype
-    local right_ft = vim.bo[pair.right.buf].filetype
-    if left_ft == "" and right_ft ~= "" then
-        vim.bo[pair.left.buf].filetype = right_ft
-    elseif right_ft == "" and left_ft ~= "" then
-        vim.bo[pair.right.buf].filetype = left_ft
-    end
     diff.set_diff(left_win, true)
     diff.set_diff(right_win, true)
     s.last_shown_key = key