bug#48695: python.el *-backspace functionality behavior

bug#48695: python.el *-backspace functionality behavior

[Mikhail P]

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Hello!

I want to report a small behavior problem of the default python.el

When hitting backspace in some context it does not delete the region 
selected (between active mark and cursor) but dedents instead.

Attaching a video and debug info below.

Thanks, Mikhail


|In GNU Emacs 27.1 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.22, 
cairo version 1.17.3)||
|| of 2020-08-29 built on juergen||
||Windowing system distributor 'The X.Org Foundation', version 
11.0.12010000||
||System Description: Arch Linux||
||
||Recent messages:||
||Please type q, s, or p; or ? for help||
||...ome/mikpom/tmp/test.py locked by mikpom@mik-PC... (pid 306092): (s, 
q, p, ?)?  [2 times]||
||point=32 of 31 (EOB) column=11||
||Quit [2 times]||
||point=32 of 31 (EOB) column=11||
||Use +,-,0 for further adjustment [7 times]||
||Mark set||
||Undo||
||Mark set||
||Undo||
||
||Configured using:||
|| 'configure --prefix=/usr --sysconfdir=/etc --libexecdir=/usr/lib||
|| --localstatedir=/var --with-x-toolkit=gtk3 --with-xft --with-wide-int||
|| --with-modules --with-cairo --with-harfbuzz 'CFLAGS=-march=x86-64||
|| -mtune=generic -O2 -pipe -fno-plt' CPPFLAGS=-D_FORTIFY_SOURCE=2||
|| LDFLAGS=-Wl,-O1,--sort-common,--as-needed,-z,relro,-z,now'||
||
||Configured features:||
||XPM JPEG TIFF GIF PNG RSVG CAIRO SOUND GPM DBUS GSETTINGS GLIB NOTIFY||
||INOTIFY ACL GNUTLS LIBXML2 FREETYPE HARFBUZZ M17N_FLT LIBOTF ZLIB||
||TOOLKIT_SCROLL_BARS GTK3 X11 XDBE XIM MODULES THREADS LIBSYSTEMD JSON||
||PDUMPER LCMS2 GMP||
||
||Important settings:||
||  value of $LANG: en_US.UTF-8||
||  locale-coding-system: utf-8-unix||
||
||Major mode: Python||
||
||Minor modes in effect:||
||  text-scale-mode: t||
||  shell-dirtrack-mode: t||
||  tooltip-mode: t||
||  global-eldoc-mode: t||
||  eldoc-mode: t||
||  electric-indent-mode: t||
||  mouse-wheel-mode: t||
||  tool-bar-mode: t||
||  menu-bar-mode: t||
||  file-name-shadow-mode: t||
||  global-font-lock-mode: t||
||  font-lock-mode: t||
||  blink-cursor-mode: t||
||  auto-composition-mode: t||
||  auto-encryption-mode: t||
||  auto-compression-mode: t||
||  line-number-mode: t||
||  transient-mark-mode: t||
||
||Load-path shadows:||
||None found.||
||
||Features:||
||(shadow sort mail-extr emacsbug message rmc puny dired dired-loaddefs||
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||cairo move-toolbar gtk x-toolkit x multi-tty make-network-process emacs)||
||
||Memory information:||
||((conses 16 68993 9337)||
|| (symbols 48 8647 1)||
|| (strings 32 25425 1979)||
|| (string-bytes 1 913938)||
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|


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bug#48695: python.el *-backspace functionality behavior

[Lars Ingebrigtsen]

Mikhail P <mikpom@fastmail.com> writes:

> I want to report a small behavior problem of the default python.el 
>
> When hitting backspace in some context it does not delete the region selected
> (between active mark and cursor) but dedents instead.
>
> Attaching a video and debug info below.

I'm unable to reproduce the problem on either Emacs 27.1 or Emacs 28.
Could you give a step-by-step recipe to reproduce the bug, starting from
"emacs -Q"?

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#48695: python.el *-backspace functionality behavior

[Lars Ingebrigtsen]

(Please keep the debbugs address in the Cc headers -- otherwise your
mails won't reach the Emacs bug tracker.)

Mikhail P <mikpom@fastmail.com> writes:

> Greetings!
>
> The steps are :
>
> 1. start emacs with emacs -Q
>
> 2. visit a (empty) file with .py extension (so built-in Python major mode is activated)
>
> 3. type a block of code containing indented line, e.g. 
>
> for i in range(10): 
>
>     print(i)
>
> 4. Move the cursor at the very end of the code example (after print(i)) and activate
> the mark
>
> 5. Move the cursor at the beginning of print(i), so it is on p.
>
> 6. hit backspace.
>
> 7. selected text (print(i)) is not deleted but dedented instead)

Thanks for the recipe -- I can reproduce this in both Emacs 28 and 27.1.

If point is anywhere else than at the "p", the <backspace> works as
expected, but if it's a the "p", it deletes the leading spaces instead.
Most peculiar.