bin/48498: sh(1) parser oddity

[dholland%netbsd.org@localhost]

>Number:         48498
>Category:       bin
>Synopsis:       sh(1) parser oddity
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    bin-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Jan 04 16:25:00 +0000 2014
>Originator:     David A. Holland
>Release:        NetBSD 6.99.28 (20131210)
>Organization:
dholland%netbsd.org@localhost
>Environment:
System: NetBSD valkyrie 6.99.28 NetBSD 6.99.28 (VALKYRIE) #14: Tue Dec 10 
15:15:49 EST 2013  dholland@valkyrie:/usr/src/sys/arch/amd64/compile/VALKYRIE 
amd64
Architecture: x86_64
Machine: amd64
>Description:

sh accepts some curious constructions; while it doesn't accept a plain
"fi", it is happy with a loose "fi" as long as it follows something else:

valkyrie% sh -c 'true; fi'
valkyrie% sh -c 'false; fi'
valkyrie% 

Similarly, it accepts "then" without "if" as long as it isn't first:

valkyrie% sh -c 'false; then echo wut'
wut
valkyrie% sh -c 'true; then echo wut'
wut
valkyrie% 

Same for "do":

valkyrie% sh -c 'true; do echo wut'
wut
valkyrie% 

For that matter you don't even need to have a command there:

valkyrie% sh -c 'true; then'
valkyrie% sh -c 'true; do'
valkyrie% 

Needless to say, ksh, bash, and zsh don't allow this sort of thing.

>How-To-Repeat:

>Fix:

torches and pitchforks