Bug#1027944: neofetch: Color blocks do not render on bash >=5.2 and can cause text overlap

[Jordan Atwood]

Package: neofetch
Version: 7.1.0-4
Severity: normal
Tags: patch upstream

Dear Maintainer,

I found that installing and using neofetch on Debian testing (bookworm),
it had different behavior than that on stable (bullseye). Namely, the
color block output using the default configuration (via the `info cols`
directive) does not work correctly. Instead of printing a grid of
terminal colors, it exits early due to a syntax error in bash 5.2 and
can cause the terminal prompt to overlap the distribution logo.

Running `neofetch -v` with the default config gives the following
output:

```
$ neofetch -v
_,met$$$$$gg. nightfirecat@debian
,g$$$$$$$$$$$$$$$P. -------------------
,g$$P" """Y$$.". OS: Debian GNU/Linux bookworm/sid x86_64
,$$P' `$$$. Host: Laptop (12th Gen Intel Core) A6
',$$P ,ggs. `$$b: Kernel: 6.0.0-6-amd64
`d$$' ,$P"' . $$$ Uptime: 37 mins
$$P d$' , $$P Packages: 2697 (dpkg), 12 (flatpak)
$$: $$. - ,d$$' Shell: bash 5.2.2
$$; Y$b._ _,d$P' Resolution: 2256x1504
Y$$. `.`"Y$$$$P"' DE: Plasma 5.26.4
`$$b "-.__ WM: KWin
grep: /etc/gtk-2.0/gtkrc: No such file or directory
`Y$$. Theme: Breeze [Plasma], Breeze [GTK2/3]
grep: /etc/gtk-2.0/gtkrc: No such file or directory
`Y$$b. Icons: [Plasma], candy-icons [GTK2/3]
`"Y$b._ Terminal: konsole
qtpaths: could not find a Qt installation of ''
/usr/bin/neofetch: line 2110: /sys/devices/system/cpu/cpu0/cpufreq/bios_limit: No sucy
/usr/bin/neofetch: line 2111: /sys/devices/system/cpu/cpu0/cpufreq/bios_limit: No sucy
CPU: 12th Gen Intel i7-1260P (16) @ 4.700GHz
GPU: Intel Alder Lake-P
Memory: 4745MiB / 15714MiB
/usr/bin/neofetch: line 3803: bad substitution: no closing `}' in ${block_spaces// /$}
```

And running `neofetch` [using my own config][1], I get this output:
(prompt is not part of neofetch; it merely overlaps it)

```
$ neofetch
_,met$$$$$gg. nightf...@debian.framework
,g$$$$$$$$$$$$$$$P. -----------------------------
,g$$P" """Y$$.". OS: Debian GNU/Linux bookworm/sid x86_64
,$$P' `$$$. Kernel: Linux 6.0.0-6-amd64
',$$P ,ggs. `$$b: Uptime: 9 mins
`d$$' ,$P"' . $$$ Packages: 2697 (dpkg), 12 (flatpak)
$$P d$' , $$P Shell: bash 5.2.2
$$: $$. - ,d$$' DE: Plasma 5.26.4
$$; Y$b._ _,d$P' WM: KWin
Y$$. `.`"Y$$$$P"' Theme: Breeze [Plasma], Breeze [GTK2/3]
`$$b "-.__ Icons: [Plasma], candy-icons [GTK2/3]
`Y$$ CPU: 12th Gen Intel i7-1260P (16) @ 4.7GHz
`Y$$. Memory: 3.63GiB / 15.35GiB (23%)
`$$b. Disk (/): 31G / 914G (4%)
`Y$$b.
[nightf...@debian.framework ~]
$ `"""
```

This bug has been [reported upstream][2], though no fix has been merged
due to apparent inactivity on the project. I found that [applying a
patch from a fork of the project][3] fixes the issue neatly without
causing regression for older bash versions. The following diff, adapted
from said patch, fixes the issue for me:

```
diff --git a/neofetch b/neofetch
index 1e4b564..effa048 100755
--- a/neofetch
+++ b/neofetch
@@ -3800,8 +3800,13 @@ get_cols() {
printf -v block_spaces "%${block_height}s"

# Convert the spaces into rows of blocks.
- [[ "$blocks" ]] && cols+="${block_spaces// /${blocks} [mnl}"
- [[ "$blocks2" ]] && cols+="${block_spaces// /${blocks2} [mnl}"
+ if [[ $BASH_VERSION == 3* ]]; then
+ [[ "$blocks" ]] && cols+="${block_spaces// /${blocks} [mnl}"
+ [[ "$blocks2" ]] && cols+="${block_spaces// /${blocks2} [mnl}"
+ else
+ [[ "$blocks" ]] && cols+="${block_spaces// /${blocks} \[mnl}"
+ [[ "$blocks2" ]] && cols+="${block_spaces// /${blocks2} \[mnl}"
+ fi

# Add newlines to the string.
cols=${cols%%nl}
```

Thanks,
Jordan

[1]: https://git.nightfirec.at/nightfirecat/dotfiles/src/commit/91ac846246fab70a99336169058d6ba301b6e538/src/.neofetch.config.json
[2]: https://github.com/dylanaraps/neofetch/issues/2195
[3]: https://github.com/hykilpikonna/hyfetch/pull/24#issuecomment-1296304767

-- System Information:
Debian Release: bookworm/sid
APT prefers testing
APT policy: (500, 'testing')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 6.0.0-6-amd64 (SMP w/16 CPU threads; PREEMPT)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

neofetch depends on no packages.

Versions of packages neofetch recommends:
ii caca-utils 0.99.beta20-3
ii chafa 1.12.4-1
ii imagemagick 8:6.9.11.60+dfsg-1.3+b4
ii imagemagick-6.q16 [imagemagick] 8:6.9.11.60+dfsg-1.3+b4
ii jp2a 1.1.1-2
ii libsixel-bin 1.10.3-3
ii pciutils 1:3.9.0-2
ii w3m-img 0.5.3+git20220429-1+b1

neofetch suggests no packages.

-- no debconf information