Date: Mon, 5 Mar 2001 09:33:56 +0200 (IST)
From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
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To: Richard Dawe <rich AT phekda DOT freeserve DOT co DOT uk>
cc: DJGPP workers <djgpp-workers AT delorie DOT com>,
        Jim Meyering <meyering AT ascend DOT com>
Subject: Re: Fetish.pm band-aid (Fileutils testsuite)
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On Sun, 4 Mar 2001, Richard Dawe wrote:

> 1. _shell_quote() generates file names enclosed in single quotes. The
> input file names are quoted using _shell_quote(). The Perl system() call
> to generate test input then fails with the error "Cannot redirect input:
> No such file or directory (ENOENT)". Presumably because this is because
> the file name gets passed on the command-line with single quotes, but the
> actual file has a file name with no quotes.

I doubt that your guess is correct (modulo unknown bugs in the
library).  Assuming that Perl calls `system' from libc, it should
handle quoted files just fine.  This feature was heavily tested when
it was introduced (circa v2.01), and is working with no known problems
ever since.

> 2. There seems to be a problem using '2> /dev/null' with the Perl system()
> call.

Do all the commands which fail redirect stderr with the "2>"
construct?  You seem to indicate that there are several failures, but
only show one example, and all your patches to Fetish.pm seem to be
related to stderr redirection.

> "Ambiguous redirect" errors are generated.

Both these messages ("Cannot redirect" and "Ambiguous redirect") are
from `system's code.  Significantly, they both indicate that `system'
is using its internal emulator of COMMAND.COM, which doesn't support
"2>" style redirection.

In other words, the test suite setup is not taking care of setting
$SHELL to point to the Bash executable.  It should do that because
these commands will never work with anything but a Unixy shell.  When
`system' sees that $SHELL points to a Unixy shell, it passes the
entire command to the shell instead of handling it on its own.  (This
is explained in the `system's docs in the library reference.)

It is quite common for Unix-born test suites to not bother setting
$SHELL, since the default shell is good enough.  But for this to work
on non-Posix platforms, $SHELL _must_ be set.

> How I encountered the problems with Fetish.pm. I am using DJGPP 2.03, bash
> 2.04, Perl 5.005_02. I tried to use the 'dd' testsuite from Fileutils
> 4.0.40 to test 'dd' from the Fileutils 4.0 DJGPP port I'm working on. With
> a similar patch (exactly same changes, but Fetish.pm is newer in 4.0.40)
> the ported 'dd' passes 'misc', 'skip-seek' and 'skip-seek2'. It fails
> 'not-rewound' - I think because of redirection issues in the script.

If the failures with `dd' are not explained by stderr redirection,
please post the test source and results (diffs of actual against
expected output).  It is impossible to reason about this without
knowing what does that test try to do.