bug#52329: Fix alignment of makefile-backslash-region

bug#52329: Fix alignment of makefile-backslash-region

[Fredrik Bergroth]

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Hi,

`makefile-backslash-region' is inserting tabs rather than spaces (due to
the major mode setting indent-tabs-mode).
The backslashes won't align properly (unless everyone agrees on a
tab-width). I attached a patch that fixes this.

Cheers!

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From 5409fec9e445eb69037e04b86a1fc457d1759610 Mon Sep 17 00:00:00 2001
From: Fredrik Bergroth <fbergroth@gmail.com>
Date: Mon, 6 Dec 2021 13:47:01 +0100
Subject: [PATCH] Fix alignment of makefile-backslash-region

* lisp/progmodes/make-mode.el (makefile-append-backslash): Ensure
`indent-to' will use spaces.
---
 lisp/progmodes/make-mode.el | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/lisp/progmodes/make-mode.el b/lisp/progmodes/make-mode.el
index df17b87c01..b2e2d8b65c 100644
--- a/lisp/progmodes/make-mode.el
+++ b/lisp/progmodes/make-mode.el
@@ -1224,13 +1224,15 @@ makefile-backslash-region
 
 (defun makefile-append-backslash (column)
   (end-of-line)
-  ;; Note that "\\\\" is needed to get one backslash.
-  (if (= (preceding-char) ?\\)
-      (progn (forward-char -1)
-             (delete-horizontal-space)
-             (indent-to column (if makefile-backslash-align nil 1)))
-    (indent-to column (if makefile-backslash-align nil 1))
-    (insert "\\")))
+  ;; Ensure `indent-to' will use spaces.
+  (let ((indent-tabs-mode nil))
+    ;; Note that "\\\\" is needed to get one backslash.
+    (if (= (preceding-char) ?\\)
+        (progn (forward-char -1)
+               (delete-horizontal-space)
+               (indent-to column (if makefile-backslash-align nil 1)))
+      (indent-to column (if makefile-backslash-align nil 1))
+      (insert "\\"))))
 
 (defun makefile-delete-backslash ()
   (end-of-line)
-- 
2.17.1

bug#52329: Fix alignment of makefile-backslash-region

[Stefan Kangas]

Fredrik Bergroth <fbergroth@gmail.com> writes:

> `makefile-backslash-region' is inserting tabs rather than spaces (due to the major mode setting indent-tabs-mode).
> The backslashes won't align properly (unless everyone agrees on a tab-width). I attached a patch that fixes this.

Thanks for the patch.

Could you provide a recipe to reproduce this problem, preferably
starting from "emacs -Q"?

bug#52329: Fix alignment of makefile-backslash-region

[Fredrik Bergroth]

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Sure!

emacs -Q --eval '(makefile-mode)' --eval '(insert "a\nbbbbb\ncc")' --eval
'(mark-whole-buffer)' --eval "(call-interactively
'makefile-backslash-region)"

This will end up with a bunch of tabs (rather than spaces) after the "a"
and the b:s. If you now change tab-width to 2, the backslashes won't align.

Den mån 6 dec. 2021 kl 14:54 skrev Stefan Kangas <stefan@marxist.se>:

> Fredrik Bergroth <fbergroth@gmail.com> writes:
>
> > `makefile-backslash-region' is inserting tabs rather than spaces (due to
> the major mode setting indent-tabs-mode).
> > The backslashes won't align properly (unless everyone agrees on a
> tab-width). I attached a patch that fixes this.
>
> Thanks for the patch.
>
> Could you provide a recipe to reproduce this problem, preferably
> starting from "emacs -Q"?
>

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bug#52329: Fix alignment of makefile-backslash-region

[Lars Ingebrigtsen]

Fredrik Bergroth <fbergroth@gmail.com> writes:

> emacs -Q --eval '(makefile-mode)' --eval '(insert "a\nbbbbb\ncc")' --eval '
> (mark-whole-buffer)' --eval "(call-interactively 'makefile-backslash-region)"
>
> This will end up with a bunch of tabs (rather than spaces) after the
> "a" and the b:s. If you now change tab-width to 2, the backslashes
> won't align.

(I'm going through old bug reports that unfortunately weren't resolved
at the time.)

The advantage of using TABs for alignment here, though, is that if you
then adjust some of the text slightly, you won't need to adjust the
alignment.

Which is much more common than altering tab-width, so I don't think we
want to do this change, and I'm therefore closing this bug report.