broke on downloading&switching 2020.08.2

[Veraellyunjie]

> rakubrew download moar 2021.02.1 # 100% OK
> rakubrew switch moar-2021.02.1   # 100% OK
> rakubrew download moar 2020.08.2 # OK as far as I recall — the terminal output scrolled beyond history

> rakubrew switch moar-2020.08.2
Switching to moar-2020.08.2
Use of uninitialized value $cur in scalar chomp at /opt/olve/rakubrew/bin/rakubrew line 2692.
Use of uninitialized value $version in string ne at /opt/olve/rakubrew/bin/rakubrew line 1223.
Use of uninitialized value in subroutine entry at /opt/olve/rakubrew/bin/rakubrew line 2777.
Use of uninitialized value $version in concatenation (.) or string at /opt/olve/rakubrew/bin/rakubrew line 2782.
Invalid version found:  at /opt/olve/rakubrew/bin/rakubrew line 2782.

> raku --version
Welcome to Rakudo(tm) v2021.02.1.
Implementing the Raku(tm) programming language v6.d.
Built on MoarVM version 2021.02.

> rakubrew switch moar-2021.07
Switching to moar-2021.07
Use of uninitialized value $cur in scalar chomp at /opt/olve/rakubrew/bin/rakubrew line 2692.
Use of uninitialized value $version in string ne at /opt/olve/rakubrew/bin/rakubrew line 1223.
Use of uninitialized value in subroutine entry at /opt/olve/rakubrew/bin/rakubrew line 2777.
Use of uninitialized value $version in concatenation (.) or string at /opt/olve/rakubrew/bin/rakubrew line 2782.
Invalid version found:  at /opt/olve/rakubrew/bin/rakubrew line 2782.

> raku --version
Welcome to Rakudo(tm) v2021.02.1.
Implementing the Raku(tm) programming language v6.d.
Built on MoarVM version 2021.02.

And in a new terminal window:

> raku
fish: Unknown command: raku

• What's the output of rakubrew rakubrew-version?:

> rakubrew rakubrew-version
rakubrew v19 Build type: fatpack OS: linux
Use of uninitialized value $cur in scalar chomp at /opt/olve/rakubrew/bin/rakubrew line 2692.
Use of uninitialized value $version in string ne at /opt/olve/rakubrew/bin/rakubrew line 1223.
Use of uninitialized value in subroutine entry at /opt/olve/rakubrew/bin/rakubrew line 2777.
Use of uninitialized value $version in concatenation (.) or string at /opt/olve/rakubrew/bin/rakubrew line 2782.
Invalid version found:  at /opt/olve/rakubrew/bin/rakubrew line 2782.

• Are you using rakubrew in env or in shim mode? (run rakubrew mode to find out):

> rakubrew mode
env
Use of uninitialized value $cur in scalar chomp at /opt/olve/rakubrew/bin/rakubrew line 2692.
Use of uninitialized value $version in string ne at /opt/olve/rakubrew/bin/rakubrew line 1223.
Use of uninitialized value in subroutine entry at /opt/olve/rakubrew/bin/rakubrew line 2777.
Use of uninitialized value $version in concatenation (.) or string at /opt/olve/rakubrew/bin/rakubrew line 2782.
Invalid version found:  at /opt/olve/rakubrew/bin/rakubrew line 2782.

• Where is rakubrew installed? (run rakubrew home to find out):

> rakubrew home
/opt/olve/rakubrew
Use of uninitialized value $cur in scalar chomp at /opt/olve/rakubrew/bin/rakubrew line 2692.
Use of uninitialized value $version in string ne at /opt/olve/rakubrew/bin/rakubrew line 1223.
Use of uninitialized value in subroutine entry at /opt/olve/rakubrew/bin/rakubrew line 2777.
Use of uninitialized value $version in concatenation (.) or string at /opt/olve/rakubrew/bin/rakubrew line 2782.
Invalid version found:  at /opt/olve/rakubrew/bin/rakubrew line 2782.

OS: antiX 19 (Debian 10 Buster without systemd)
shell: fish

[Veraellyunjie]

My fault, run out of space.
I feature-request rakubrew checking for available storage space

[patrickbkr]

@ithgub Thanks for the bug report and idea of checking for disk space. I have pondered the idea and I think I won't add logic to do this for two reasons:

• It's difficult to reliably detect out of disk space conditions, as the space can run out in arbitrary moments and thus cause arbitrary failure modes in many different code paths.
• I know few (if not no) other programs that check for out of disk space conditions. So in an out of space condition typically all sorts of programs start to behave strangely. I myself have developed a sensibility to check for the free space if programs suddenly start failing. I think it's improbable for someone to run into an out of disk space condition and not realize it soonish afterwards.

I hope this reasoning makes sense to you.