[perl #130455] Should I be able to change the temporary directory?

[brian d foy]

# New Ticket Created by  "brian d foy" 
# Please include the string:  [perl #130455]
# in the subject line of all future correspondence about this issue. 
# <URL: https://rt.perl.org/Ticket/Display.html?id=130455 >


tmpdir doesn't appear to change directories. This is probably why I
had the problem with https://rt.perl.org/Ticket/Display.html?id=130454
(although I should have had a different error there).

It's not documented to do that in the various IO::Spec modules, but I was
trying stuff in S16 to see what works. Should I be able to change the temporary
directory as S16 says, or is it forever fixed and should be documented as
read-only?

    my $dir = '/Users/brian';
    my $dir-io = $dir.IO;

    put "$dir is a dir:      " ~ $dir-io.d;
    put "$dir is readable:   " ~ $dir-io.r;
    put "$dir is executable: " ~ $dir-io.x;
    put "$dir is writeable:  " ~ $dir-io.w;

    tmpdir( $dir )

It looks like everything should work, but it doesn't:

    /Users/brian is a dir:      True
    /Users/brian is readable:   True
    /Users/brian is executable: True
    /Users/brian is writeable:  True
    Cannot modify an immutable IO::Path
      in block <unit> at /Volumes/Big Scratch/Dropbox/~~Writing/Perl
Writing/LearningPerl6/learning_perl_6/scratch/file_trials.p6 line 11

Or, assigning to it directly:

    my $dir = '/Users/brian';
    my $dir-io = $dir.IO;

    put "$dir is a dir:      " ~ $dir-io.d;
    put "$dir is readable:   " ~ $dir-io.r;
    put "$dir is executable: " ~ $dir-io.x;
    put "$dir is writeable:  " ~ $dir-io.w;

    $*TMPDIR = $dir;

It says I can't assign to $*TMPDIR. How is it that I can't assign to
dynamic variable? What's the point of it being dynamic if it can't change?

    Cannot modify an immutable IO::Path
      in block <unit> at /Volumes/Big Scratch/Dropbox/~~Writing/Perl
Writing/LearningPerl6/learning_perl_6/scratch/file_trials.p6 line 11

Try it with my:

    my $dir = '/Users/brian';
    my $dir-io = $dir.IO;

    put "$dir is a dir:      " ~ $dir-io.d;
    put "$dir is readable:   " ~ $dir-io.r;
    put "$dir is executable: " ~ $dir-io.x;
    put "$dir is writeable:  " ~ $dir-io.w;

    my $*TMPDIR;

    tmpdir( $dir )

Now it's a different sort of error. This kinda makes sense because there's
nothing in $*TMPDIR and tmpdir expects IO::Spec. But why is the error in
chdir and not something that catches that the argument wasn't IO::Spec?

    /Users/brian is a dir:      True
    /Users/brian is readable:   True
    /Users/brian is executable: True
    /Users/brian is writeable:  True
    No such method 'chdir' for invocant of type 'Any'
      in block <unit> at /Volumes/Big Scratch/Dropbox/~~Writing/Perl
Writing/LearningPerl6/learning_perl_6/scratch/file_trials.p6 line 13

Use temp instead, and it's a different error (despite that temp was
used for this purpose in S16):

    my $dir = '/Users/brian';
    my $dir-io = $dir.IO;

    put "$dir is a dir:      " ~ $dir-io.d;
    put "$dir is readable:   " ~ $dir-io.r;
    put "$dir is executable: " ~ $dir-io.x;
    put "$dir is writeable:  " ~ $dir-io.w;

    temp $*TMPDIR;

    tmpdir( $dir )

Now it's a different sort of error:

    /Users/brian is a dir:      True
    /Users/brian is readable:   True
    /Users/brian is executable: True
    /Users/brian is writeable:  True
    Can only use 'temp' on a container
      in block <unit> at /Volumes/Big Scratch/Dropbox/~~Writing/Perl
Writing/LearningPerl6/learning_perl_6/scratch/file_trials.p6 line 11