bin/79063: grep(1) - strange behaviour (most likely a bug) -- `grep -i --colour ""`

[martinko]

>Number:         79063
>Category:       bin
>Synopsis:       grep(1) - strange behaviour (most likely a bug) -- `grep -i --colour ""`
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sun Mar 20 22:30:02 GMT 2005
>Closed-Date:
>Last-Modified:
>Originator:     martinko
>Release:        5.3R-p5
>Organization:
>Environment:
FreeBSD mb-aw1n-bsd 5.3-RELEASE-p5 FreeBSD 5.3-RELEASE-p5 #5: Mon Feb 14 19:45:04 CET 2005     root at mb-aw1n-bsd:/usr/obj/usr/src/sys/MB-AW1N  i386

>Description:
      `grep -i --colour ""` runs mad and seems to generate ansi escape codes in a (infinite?) loop. it happens only when using empty ("") search string and both parameters (-i and --colour) are used.
pls find my orginal description below as posted to freebsd-questions mailing list. i also produced a typescript with script(1) which you may find under the 2nd link/post.

http://lists.freebsd.org/pipermail/freebsd-questions/2005-March/081083.html
http://lists.freebsd.org/pipermail/freebsd-questions/2005-March/081202.html

>How-To-Repeat:
      just run the following:
grep -i --colour ""
as soon as you type the first letter it gets mad and soon you'll have a huge typescript file as you can see in the link above.
codes/chars generated (as output on screen) seem to be random but i'm not sure about it.
>Fix:
      sorry, i've no idea. but if you need my assistence just let me know pls.
>Release-Note:
>Audit-Trail:
>Unformatted: