From @briandfoy

If the HOME environment variable is not set (say, as in
non-interactive sessions), using $*HOME throws an exception​:

  $ unset HOME
  $ echo $HOME

  $ perl6 -e 'put "HOME is $*HOME"'
  Use of uninitialized value of type Any in string context.
  Methods .^name, .perl, .gist, or .say can be used to stringify it
to something meaningful.
  in block <unit> at -e line 1
  HOME is

Curiously, $*TMPDIR is /tmp if the TMPDIR environment variable is not
set.

Maybe that's good and maybe not. But, trying to use homedir blows up the
same way tmpdir does (https://rt-archive.perl.org/perl6/Ticket/Display.html?id=130455):

  $ perl6 -e 'homedir( "/Users/brian" ); put "HOME is $*HOME"'
  No such method 'chdir' for invocant of type 'Any'
  in block <unit> at -e line 1

But, homedir isn't documented outside of S16 even though it appears to
be there somewhere. Trying to set $*HOME directly doesn't work either,
which is certainly perplexing​:

  $ perl6 -e '$*HOME = "/Users/brian"; put "HOME is $*HOME"'
  Cannot modify an immutable Any
  in block <unit> at -e line 1

I can set a key is a completely different variable to get it to work​:

  $ perl6 -e '%*ENV<HOME> = "/Users/brian"; put "HOME is $*HOME"'
  HOME is /Users/brian

And I can even set it to a directory that does not exist​:

  $ perl6 -e '%*ENV<HOME> = "/Users/brian/not-there"; put "HOME is $*HOME"'
  HOME is /Users/brian/not-there

The $*HOME variable is listed in . If it isn't set, it's documented to
be Nil, but it is apparently Any. That also appears to mess with the REPL​:

  $ perl6
  I ran into a problem while trying to set up Linenoise​: Cannot
resolve caller new(IO​::Path​: Any); none of these signatures match​:
  (IO​::Path $​: Cool $path, :$SPEC = { ... }, :$CWD = { ... }, *%_)
  (IO​::Path $​: :$basename!, :$dirname = "", :$volume = "",
:$SPEC = { ... }, :$CWD = { ... }, *%_)
  (IO​::Path $​: *%_)
  Continuing without tab completions or line editor
  You may want to consider using rlwrap for simple line editor functionality

  To exit type 'exit' or '^D'
  > $*HOME
  (Any)
  >

From @zoffixznet

On Fri, 30 Dec 2016 01​:06​:35 -0800, comdog wrote​:

If the HOME environment variable is not set (say, as in
non-interactive sessions), using $*HOME throws an exception​:

$ unset HOME
$ echo $HOME

$ perl6 -e 'put "HOME is $*HOME"'
Use of uninitialized value of type Any in string context.
Methods .^name, .perl, .gist, or .say can be used to stringify it
to something meaningful.
in block <unit> at -e line 1
HOME is

Curiously, $*TMPDIR is /tmp if the TMPDIR environment variable is not
set.

Maybe that's good and maybe not. But, trying to use homedir blows up
the
same way tmpdir does
(https://rt-archive.perl.org/perl6/Ticket/Display.html?id=130455):

$ perl6 -e 'homedir( "/Users/brian" ); put "HOME is $*HOME"'
No such method 'chdir' for invocant of type 'Any'
in block <unit> at -e line 1

But, homedir isn't documented outside of S16 even though it appears to
be there somewhere. Trying to set $*HOME directly doesn't work either,
which is certainly perplexing​:

$ perl6 -e '$*HOME = "/Users/brian"; put "HOME is $*HOME"'
Cannot modify an immutable Any
in block <unit> at -e line 1

I can set a key is a completely different variable to get it to work​:

$ perl6 -e '%*ENV<HOME> = "/Users/brian"; put "HOME is $*HOME"'
HOME is /Users/brian

And I can even set it to a directory that does not exist​:

$ perl6 -e '%*ENV<HOME> = "/Users/brian/not-there"; put "HOME is
$*HOME"'
HOME is /Users/brian/not-there

The $*HOME variable is listed in . If it isn't set, it's documented to
be Nil, but it is apparently Any. That also appears to mess with the
REPL​:

$ perl6
I ran into a problem while trying to set up Linenoise​: Cannot
resolve caller new(IO​::Path​: Any); none of these signatures match​:
(IO​::Path $​: Cool $path, :$SPEC = { ... }, :$CWD = { ... }, *%_)
(IO​::Path $​: :$basename!, :$dirname = "", :$volume = "",
:$SPEC = { ... }, :$CWD = { ... }, *%_)
(IO​::Path $​: *%_)
Continuing without tab completions or line editor
You may want to consider using rlwrap for simple line editor
functionality

To exit type 'exit' or '^D'

$*HOME
(Any)

Thank you for the report. All the points in this ticket are now resolved​:

- "If HOME env var unset, using $*HOME throws an exception"
  - That's just a stringified-undef warning. You can use `quietly` to quiet it.
- "Trying to use homedir blows up"
  - &homedir has been removed; use $*HOME directly
- "Trying to set $*HOME directly doesn't work either"
  - That was fixed[^1] by lizmat and is available in 2017.04 compiler release; tests in [^2]
- "It's documented to be Nil, but it is apparently Any"
  - This is now fixed[^3] and tested[^4] to be Nil; will be in 2017.05 release
- "I can even set it to a directory that does not exist"
  - After a discussion[^5] (a soliloquy?), I think that behaviour is most desirable
- "That also appears to mess with the REPL"
  - This is now fixed[^6] (will be in 2017.05 release).
  For testing this, added a TODO note into Rakudo's test suite, since the test
  requires Linenoise/Readline to be installed.

[^1] rakudo/rakudo@1b9d53c
[^2] Raku/roast@2d9194fff9
[^3] rakudo/rakudo@7412184fcd
[^4] Raku/roast@71a6423a99
[^5] https://irclog.perlgeek.de/perl6-dev/2017-04-27#i_14496170
[^6] rakudo/rakudo@1b0e41f972

The RT System itself - Status changed from 'new' to 'open'

@zoffixznet - Status changed from 'open' to 'resolved'