[Bug-readline] mark-modified-lines bug

[J Pelkey]

Readline version: 5.2 with patches: readline52-001
Bash version    : 3.2.10(1)
Processor       : AMD Athlon 64 X2
Compiler        : 64-bit gcc 3.4.6
OS Kernel       : 64-bit Gentoo Linux 2.6.17-gentoo-r8


I tested only in bash, and the bug affects both the readline package and 
the readline distributed with bash (I assume it's not a bash bug 
itself).  If mark-modified-lines is on in /etc/inputrc, and you go to a 
previous history line and press backspace, instead of an asterisk 
appearing before the prompt and the line being shifted over 1 column, 
the prompt gets rewritten where it previously was (no * prepending it), 
and an extra space appears between the prompt and the input.  I've only 
checked it when TERM=linux and in the linux console and KDE's konsole.  
What appears to be output to terminal (I tested with a typescript) is 
upon the first backspace:
'^H ^H'
carriage return
the linux console code 'ESC[1@'
'*'
another carriage return
the prompt
a space
the correct input line

According to linux's console_codes man page, 'ESC[#@' does: Insert the 
indicated # of blank characters.

What is output (correctly) if I append to a line in history is:
carriage return
'*'
the prompt
the correct input line


This bug doesn't seem to affect backspaces after the line has already 
been marked as modified.  The exact steps I took to find this bug in 
bash were to type:
abc<enter><up arrow><backspace>



--Joe Pelkey