Re: [IDEA] Add function clean-buffer

[Joseph Turner <joseph@breatheoutbreathe.in>]

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Philip Kaludercic <philipk@posteo.net> writes:

> Joseph Turner <joseph@breatheoutbreathe.in> writes:
>
>> Prompted by Daniel Mendler's comment here:
>>
>> https://github.com/emacs-compat/compat/issues/27#issuecomment-1704381157
>>
>> IIUC, clean-mode is intended for interactive, debugging usage.  I am
>> interested in a function that performs some of the internal behavior of
>> the Emacs 29 clean-mode in non-interactive use.  Note that
>> yank-excluded-properties is not set in clean-buffer.
>
> Perhaps you could explain what the concrete example is where you need
> the functionality?

In hyperdrive.el, when writing an existing buffer to a hyperdrive file,
we want to first remove overlays, text properties, and local variables,
and then use set-auto-mode to set the major mode (along with its
overlays, text properties, and local variable). The reason for doing
this is so that after writing a buffer to a file, users will see the
buffer as it will appear on another peer's machine.

For example, if you call hyperdrive-write-buffer on a magit log buffer,
we want the overlays to disappear so that users don't expect others to
be able to see the overlays when they load the file.

>> (defun clean-buffer (&optional buffer)
>>   "Remove all local variables, overlays, and text properties in BUFFER.
>> When BUFFER is nil, act on current buffer."
>>   (with-current-buffer (or buffer (current-buffer))
>>     (kill-all-local-variables t)
>>     (let ((inhibit-read-only t))
>>       (dolist (overlay (overlays-in (point-min) (point-max)))
>>         (delete-overlay overlay))
>>       (set-text-properties (point-min) (point-max) nil))))
>>
>> It could also be used internally in clean-mode.
>
> Could you prepare this as a patch?

See attached patches. I'm not sure if subr.el is the right place for
this change, and I haven't added added to the NEWS file.


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From 6253633af98240f1f3ad2d00888cec945de5d708 Mon Sep 17 00:00:00 2001
From: Joseph Turner <joseph@breatheoutbreathe.in>
Date: Tue, 5 Sep 2023 12:28:49 -0700
Subject: [PATCH 1/2] Add new function clean-buffer

* lisp/subr.el (clean-buffer):
Removes all local variables, overlays, and text properties.
---
 lisp/subr.el | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/lisp/subr.el b/lisp/subr.el
index 6cedaffa806..cd4149c0a79 100644
--- a/lisp/subr.el
+++ b/lisp/subr.el
@@ -4694,6 +4694,16 @@ Normally, mouse motion is ignored."
   (declare (debug (def-body)) (indent 0))
   `(internal--track-mouse (lambda () ,@body)))
 
+(defun clean-buffer (&optional buffer)
+  "Remove all local variables, overlays, and text properties in BUFFER.
+ When BUFFER is nil, act on current buffer."
+  (with-current-buffer (or buffer (current-buffer))
+    (kill-all-local-variables t)
+    (let ((inhibit-read-only t))
+      (dolist (overlay (overlays-in (point-min) (point-max)))
+        (delete-overlay overlay))
+      (set-text-properties (point-min) (point-max) nil))))
+
 (defmacro with-current-buffer (buffer-or-name &rest body)
   "Execute the forms in BODY with BUFFER-OR-NAME temporarily current.
 BUFFER-OR-NAME must be a buffer or the name of an existing buffer.
-- 
2.41.0


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From dfb0ac3d7ae03d8e9dffd1d447afe0a604a49960 Mon Sep 17 00:00:00 2001
From: Joseph Turner <joseph@breatheoutbreathe.in>
Date: Tue, 5 Sep 2023 12:34:23 -0700
Subject: [PATCH 2/2] Refactor clean-mode to use clean-buffer

* lisp/simple.el (clean-mode):
Use clean-mode internally. Clarify docstring.
---
 lisp/simple.el | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/lisp/simple.el b/lisp/simple.el
index 05a3c4b93d6..37d76c174dc 100644
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -546,13 +546,11 @@ Other major modes are defined by comparison with this one."
   (run-mode-hooks))
 
 (define-derived-mode clean-mode fundamental-mode "Clean"
-  "A mode that removes all overlays and text properties."
-  (kill-all-local-variables t)
-  (let ((inhibit-read-only t))
-    (dolist (overlay (overlays-in (point-min) (point-max)))
-      (delete-overlay overlay))
-    (set-text-properties (point-min) (point-max) nil)
-    (setq-local yank-excluded-properties t)))
+  "Mode removing all local variables, overlays, and text properties.
+This mode is intended for debugging purposes. For non-interactive
+use, see `clean-buffer'."
+  (clean-buffer)
+  (setq-local yank-excluded-properties t))
 
 ;; Special major modes to view specially formatted data rather than files.
 
-- 
2.41.0