bug#46701: [PATCH] small cleanups related to `unlock-buffer'

[Eli Zaretskii]

> From: Matt Armstrong <matt@rfc20.org>
> Date: Sun, 21 Feb 2021 20:18:44 -0800
> 
> Subject: [PATCH 1/4] Remove unecessary (unlock-buffer) calls.
> 
> * lisp/type-break.el (type-break-mode): Remove an (unlock-buffer) call
> implied by (set-buffer-modified nil).
> * lisp/simple.el (primitive-undo): ditto.

My reading of the code is that the above is true only if
inhibit-modification-hooks is nil.  Otherwise, these calls are not
no-ops.

> --- a/lisp/files.el
> +++ b/lisp/files.el
> @@ -6234,11 +6234,8 @@ revert-buffer-insert-file-contents--default-function
>               "Cannot revert unreadable file %s")
>             file-name))
>     (t
> -    ;; Bind buffer-file-name to nil
> -    ;; so that we don't try to lock the file.
> -    (let ((buffer-file-name nil))
> -      (or auto-save-p
> -          (unlock-buffer)))
> +    (unless auto-save-p
> +      (unlock-buffer))

And here, I think we just forgot to update the Lisp code when
unlock-buffer started to look at buffer-file-truename instead of
buffer-file-name.  But otherwise, I see no reason why we should remove
the call to unlock-buffer; what did I miss?

Thanks.