Re: Weird problem with git-submodule.sh

On 12-12-07 03:23 PM, Junio C Hamano wrote:

Marc Branchaud [off-list ref] writes:

quoted

    sh-setup: protect from exported IFS

    Many scripted Porcelains rely on being able to split words at the
    default $IFS characters, i.e. SP, HT and LF.  If the user exports a
    non-default IFS to the environment, what they read from plumbing
    commands such as ls-files that use HT to delimit fields may not be
    split in the way we expect.

    Protect ourselves by resetting it, just like we do so against CDPATH
    exported to the environment.

    Noticed by Andrew Dranse [off-list ref].

    Signed-off-by: Junio C Hamano [off-list ref]

Perhaps IFS should be set to " \t\n" (which I believe is sh's default)
instead of just unsetting it altogether?

POSIX.1 says this:

    IFS - A string treated as a list of characters that is used for
    field splitting and to split lines into fields with the read
    command.  If IFS is not set, it shall behave as normal for an
    unset variable, except that field splitting by the shell and
    line splitting by the read command shall be performed as if the
    value of IFS is <space> <tab> <newline>; see Field Splitting.

    Implementations may ignore the value of IFS in the environment, or
    the absence of IFS from the environment, at the time the shell is
    invoked, in which case the shell shall set IFS to <space> <tab>
    <newline> when it is invoked.

Not to defend anyone, but I can understand how an implementer might think
they're complying with the above while still deciding that an explicit "unset
IFS" means IFS=''.

		M.