test broken on cygwin

[mokko]

I tried Alien::Base right now, but File::chdir doesn't test well on my cygwin... I start looking into it now.

looks like mkdir makes a directory, but one which has no /n in it, it returns success anyways.
local $CWD = $Test_Dir fails because dir with /n in name doesn't exist.

not sure where the error is and how to solve it.

PERL_DL_NONLAZY=1 /usr/bin/perl.exe "-MExtUtils::Command::MM" "-e" "test_harness(0, 'blib/lib', 'blib/arch')" t/*.t
t/00-compile.t .... ok
t/array.t ......... ok
t/chdir.t ......... ok
t/delete-array.t .. ok
t/nested.t ........ ok
t/newline.t ....... Cannot chdir back to /home/maurice/projects/File-chdir-0.1007/t/testdir3492: No such file or directory at /home/maurice/projects/File-chdir-0.1007/blib/lib/File/chdir.pm line 21.
t/newline.t ....... Dubious, test returned 2 (wstat 512, 0x200)
No subtests run
t/var.t ........... ok

[dagolden]

Thanks for looking into it. File::chdir is a PITA. You could also suggest that Alien::Base switch to File::pushd, which works fine on Cygwin.

[mokko]

will do. Thx for fast feedback.

[jberger]

After several conversations along these lines, I still find myself liking File::chdir more than File::pushd, the latter being far less powerful. For example, I can keep moving up a tree easiiy:

local $CWD = $self->alien_temp_dir;
# ... download and extract a tarball here
push @CWD, $ae->extract_path
# ... build etc

or I can change multiple directories by

local $CWD;
push @CWD, qw/t system_installed/;

rather than

File::pushd->new( File::Spec->catdir( qw/ t system_installed / ) );

All that said, how much work does File::chdir need? I'm willing to help (though I'm stretched pretty thin as it is right now).

[jberger]

I can't help but notice that the error being thrown by File::chdir (checking that chdir succeeds) is not checked by File::pushd. As the same function (CORE::chdir) is doing the chdir-ing, I cannot see how one succeeds and the other fails.

[jberger]

On further digging, not only does File::pushd not check the status of chdir, but the test suite does not test for directories with newlines anyway. Thus I'm rather certain that the reason File::pushd tests succeed where File::chdir does not is that the tests are not broad enough for the latter, not that that the former is inferior.

Another nit, File::chdir's t/newline.t creates a nested directory in a distinctly unsatisfying way. I would think that one would want do

local $CWD = 't';
my $Test_Dir = "testdir$$\ntest";
my $Can_mkdir_With_Newline = mkdir $Test_Dir;

Finally the fact that the thrown error is not the one from File::chdir::_chdir AND that it mentions the directory without a newline, tells me that it is Perl throwing the error and most like that it is its chdir function for Cygwin doing it. Note that the error should be:

Cannot chdir back to /home/maurice/projects/File-chdir-0.1007/t/testdir3492
test: No such file or directory at /home/maurice/projects/File-chdir-0.1007/blib/lib/File/chdir.pm line 21.

[jberger]

I believe this is a bug in Perl!

1. On cygwin abs_path is mapped to fast_abs_path for some reason. We can also know that this is true, because this is where that specific text of the error is found.
2. Unlike File::chdir, Cwd::fast_abs_path untaints without the /s flag, truncating any directories with newlines in them.

(Strangely I think I am proposing that it is File::chdir::Scalar::FETCH throwing this error, not STORE (though it may be both)! Again the real bug seems to be in Cwd::fast_abs_path)

Do you all concur? Should I file a bug on Perl?

[jberger]

@mokko can you test something on cygwin? Not using Perl, create a directory with a newline in it and cd into it. Then run

perl -MCwd -e "print Cwd::abs_path"

If that dies we have a bug in Perl.

[jberger]

Sorry for lots of noise, but of course I can try it on linux and just use the fast_abs_path and indeed it dies

$ mkdir 'hello
world'
$ cd 'hello
world'
$ perl -MCwd -E 'say Cwd::fast_abs_path'
Cannot chdir back to /home/joel/Desktop/test/hello: No such file or directory at -e line 1

[mokko]

I don't understand all details, but I get the gist. As you suspected, perl on cygwin returns
Cannot chdir back to /home/maurice/directory: No such file or directory at -e line 1.
when the oneliner is executed from with directory with newline.

[jberger]

Filed bug on Perl: RT#115962

[mokko]

sounds plausible to me. It doesn't resolve the test failure, though. We need to change t/newline.t also to use getcwd instead of abs_path. Do you want me to provide a PR? Or do you want to change it yourself, dagoldern? It's only one pretty obvious line.

[jberger]

(repeated for clarity) My full pull request has addressed these concerns: #4

[dagolden]

Fixed and released to CPAN.