Configuration Information [Automatically generated, do not change]:
Machine: x86_64
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS: -DPROGRAM='bash' -DCONF_HOSTTYPE='x86_64'
-DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='x86_64-pc-linux-gnu'
-DCONF_VENDOR='pc' -DLOCALEDIR='/usr/share/locale' -DPACKAGE='bash' -DSHELL
-DHAVE_CONFIG_H -I. -I../. -I.././include -I.././lib -Wdate-time
-D_FORTIFY_SOURCE=2 -g -O2 -fdebug-prefix-map=/build/bash-vEMnMR/bash-4.4.18=.
-fstack-protector-strong -Wformat -Werror=format-security -Wall
-Wno-parentheses -Wno-format-security
uname output: Linux desktop 5.0.3-050003-generic #201903191333 SMP Tue Mar 19
13:35:24 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux
Machine Type: x86_64-pc-linux-gnu
Bash Version: 4.4
Patch Level: 19
Release Status: release
Description:
When setting up a complex PS1 prompt where parts of the
prompt is expanded on every new prompt displayed by bash
the escape sequences that are generated by that dynamic
part are handled improperly (read: not at all).
The desired behaviour should treat such escapes for e.g.
the sequences \[ and \] equal both when the prompt expands
to stuff\[stuff\]stuff, regardless of whether this was
reached by "stuff$(echo \[stuff\])stuff" (\[\] handled) or
reached by 'stuff$(echo \[stuff\])stuff' (not handled) being
set as the value of PS1.
Repeat-By:
To demonstrate this odd behaviour assume some command
that displays changing information at each invokation:
__test1(){ echo -e "Random is \\[\e[37;1m\\]$RANDOM\e[0m"; }
Now let's assume two cases:
Case 1:
PS1='Test$(__test1)Test\[\e[0m\]$ '
-> Shows \[\] markers, includes output of $(__test1) dynamically
Case 2:
PS1="Test$(__test1)Test\[\e[0m\]$ "
-> Displays correct, but statically includes output of $(__test1)
The desired behaviour is dynamic inclusion of $(__test1) as with
case 1 while having the \[\] markers respected as seen in case 2.
Splitting the output of __test1 to separate sections with
\[\] markers and such which don't need them is not possible,
as the number of such sections may vary and the limited syntax
of PS1 does not allow for loops and other conditional constructs
on its top level.
Also leaving out the \[\] markers from __test1 will cause the
displayed prompt to misbehave.
Fix:
Move handling of \[ and \] markers to be done on the fully
expanded, representation of the PS1 variable after variable
substitutions and subshell output have been inserted.
