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Describe a Solaris /bin/sh bug w.r.t. for loops.

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Fix the commit (forgot to 'git add .').

* doc/autoconf.texi (Limitations of Shell Builtins) <for>:
Document a bug of the 'for' builtin in Solaris /bin/sh, w.r.t.
tokens seeming variable assignment in the list of arguments.

Signed-off-by: Eric Blake <eblake@redhat.com>
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Stefano Lattarini 2010-07-02 18:14:52 +02:00 committed by Eric Blake
parent a20b49a348
commit b6a515746a
2 changed files with 11 additions and 28 deletions
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@ -1,12 +1,10 @@
2010-07-02 Stefano Lattarini <stefano.lattarini@gmail.com>
Eric Blake <eblake@redhat.com>
and Eric Blake <eblake@redhat.com>
Describe a Solaris /bin/sh bug w.r.t. for loops.
* doc/autoconf.texi (Limitations of Shell Builtins) <for>:
Document a bug of the 'for' builtin in Solaris /bin/sh, w.r.t.
tokens seeming variable assignment in the list of arguments.
Report and final patch by Stefano Lattarini, useful suggestions
by Eric Blake.
tokens seeming variable assignment in the list of arguments.
2010-06-23 Ralf Wildenhues <Ralf.Wildenhues@gmx.de>

33
doc/autoconf.texi
View File

@ -16705,43 +16705,28 @@ item @samp{$@@}, for more.
In Solaris @command{/bin/sh}, when the list of arguments of a
@command{for} loop starts with @emph{unquoted} tokens looking like
variable assignments, the loop is not executed on that tokens:
variable assignments, the loop is not executed on those tokens:
@example
$ @kbd{/bin/sh -c 'for v in a=b; do echo "$v"; done'}
$ @kbd{/bin/sh -c 'for v in a=b d=c; do echo "$v"; done'}
$ @kbd{/bin/sh -c 'for v in a=b x; do echo "$v"; done'}
$ @kbd{/bin/sh -c 'for v in a=b c=d x e=f; do echo $v; done'}
x
e=f
@end example
@noindent
Quoting the "assignment-like" tokens, or preceding them with "normal"
tokens, solves the problem:
Thankfully, quoting the assignment-like tokens, or starting the list
with other tokens (including unquoted variable expansion that results in
an assignment-like result), avoids the problem, so it is easy to work
around:
@example
$ @kbd{/bin/sh -c 'for v in "a=b"; do echo "$v"; done'}
$ @kbd{/bin/sh -c 'for v in "a=b"; do echo $v; done'}
a=b
$ @kbd{/bin/sh -c 'for v in x a=b; do echo "$v"; done'}
x
a=b
$ @kbd{/bin/sh -c 'for v in x a=b d=c; do echo "$v"; done'}
x
$ @kbd{/bin/sh -c 'x=a=b; for v in $x c=d; do echo $v; done'}
a=b
c=d
@end example
@noindent
Luckily enough, the bug is not triggered if the "assignment-like"
tokens are the results of a variable expansion (even unquoted):
@example
$ @kbd{/bin/sh -c 'x="a=b"; for v in $x; do echo "$v"; done'}
a=b
@end example
@noindent
So, at least, the bug should be easy to grep for and to avoid.
@anchor{if}
@item @command{if}
@c ---------------