Homebrew-core: Using perl's local::lib does not work as stated in caveat

[iokill]

Please always follow these steps:

• [x] Confirmed this is a problem with only one, specific formula and not Homebrew/brew? If it's a general Homebrew/brew problem please file this issue at https://github.com/Homebrew/brew/issues/new
• [x] Ran brew update and retried your prior step?
• [x] Ran brew doctor, fixed as many issues as possible and retried your prior step?
• [x] Ran brew gist-logs <formula> (where <formula> is the name of the formula that failed) and included the output link?

$ brew gist-logs perl
Error: No logs.

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HOMEBREW_VERSION: 1.2.0
ORIGIN: https://github.com/Homebrew/brew
HEAD: 8cba0352e0be94263e2ed96c98bf93d8f2fce8ef
Last commit: 6 days ago
Core tap ORIGIN: https://github.com/Homebrew/homebrew-core
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Core tap last commit: 8 hours ago
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  docker

Hi!

While trying to solve #12870 I encountered the issue that using local::lib does not work unless you manually sudo chown -R <username> ~/perl5.

In more detail:
The caveat for perl states:

$ brew info perl
perl: stable 5.24.1 (bottled), HEAD
<snip>
==> Caveats
By default non-brewed cpan modules are installed to the Cellar. If you wish
for your modules to persist across updates we recommend using `local::lib`.

You can set that up like this:
  PERL_MM_OPT="INSTALL_BASE=$HOME/perl5" cpan local::lib
  echo 'eval "$(perl -I$HOME/perl5/lib/perl5 -Mlocal::lib)"' >> ~/.bash_profile

Running

PERL_MM_OPT="INSTALL_BASE=$HOME/perl5" cpan local::lib

produced a whole lot of output and prompts for the password to do a final sudo /usr/bin/make install. It did exit successfully and created ~/perl5 containing two folders man and lib.

Running the second command which adds

eval "$(perl -I$HOME/perl5/lib/perl5 -Mlocal::lib)"

to my ~/.bash_profile works too, but leads to the following error when sourcing ~/.bash_profile:

$ source .bash_profile
Attempting to create directory /Users/iokill/perl5
Unable to create /Users/iokill/perl5/bin: No such file or directory at /Users/iokill/perl5/lib/perl5/local/lib.pm line 686.
BEGIN failed--compilation aborted.

A bit of digging showed, that ~/perl5 is owned by root, so this command fails because it cannot create ~/perl5/bin when run as non-root user.
A manual sudo chown -R iokill ~/perl5/ seemed to do the trick however and also allows me to do cpan <module> as non-root.

It looks to me like this is something that should be mentioned in the caveat.

[dunn]

Good catch! Even better could be to figure out how to call cpan without requiring sudo.

[JCount]

Normally, doing this should not, and does not, require the use of sudo. There is very likely something external causing this, perhaps permissions/ownership related. Since cpan is normally owned and run by the user, it should be able to install to $HOME and create the ~/perl5 directory and its subdirs without issue. I think assuming the caveat to be incorrect at this point is a tad hasty.

@iokill Would you mind checking the permissions and ownership of both your Homebrew installation, especially perl/cpan, as well as your home directory, including those of the directory itself?

There is seemingly nothing, either in running cpan local::lib or creating the required directories, that should require elevated privileges under normal circumstances.

[DomT4]

Can you provide a full reproduction here? I've ran this through a whole bunch of times without hitting it.

Loading internal null logger. Install Log::Log4perl for logging messages
Reading '/Users/xyz/.cpan/Metadata'
  Database was generated on Sat, 06 May 2017 14:53:58 GMT
Fetching with HTTP::Tiny:
http://www.cpan.org/authors/01mailrc.txt.gz
Reading '/Users/xyz/.cpan/sources/authors/01mailrc.txt.gz'
............................................................................DONE
Fetching with HTTP::Tiny:
http://www.cpan.org/modules/02packages.details.txt.gz
Reading '/Users/xyz/.cpan/sources/modules/02packages.details.txt.gz'
  Database was generated on Thu, 11 May 2017 00:54:00 GMT
  HTTP::Date not available
.............
  New CPAN.pm version (v2.16) available.
  [Currently running version is v2.1101]
  You might want to try
    install CPAN
    reload cpan
  to both upgrade CPAN.pm and run the new version without leaving
  the current session.


...............................................................DONE
Fetching with HTTP::Tiny:
http://www.cpan.org/modules/03modlist.data.gz
Reading '/Users/xyz/.cpan/sources/modules/03modlist.data.gz'
DONE
Writing /Users/xyz/.cpan/Metadata
Running install for module 'local::lib'
Checksum for /Users/xyz/.cpan/sources/authors/id/H/HA/HAARG/local-lib-2.000019.tar.gz ok
'YAML' not installed, will not store persistent state
Configuring H/HA/HAARG/local-lib-2.000019.tar.gz with Makefile.PL

Checking if your kit is complete...
Looks good
Generating a Unix-style Makefile
Writing Makefile for local::lib
Writing MYMETA.yml and MYMETA.json
  HAARG/local-lib-2.000019.tar.gz
  /usr/local/Cellar/perl/5.24.1/bin/perl Makefile.PL -- OK
Running make for H/HA/HAARG/local-lib-2.000019.tar.gz
cp lib/lib/core/only.pm blib/lib/lib/core/only.pm
cp lib/local/lib.pm blib/lib/local/lib.pm
cp lib/POD2/PT_BR/local/lib.pod blib/lib/POD2/PT_BR/local/lib.pod
cp lib/POD2/DE/local/lib.pod blib/lib/POD2/DE/local/lib.pod
Manifying 4 pod documents
  HAARG/local-lib-2.000019.tar.gz
  /usr/bin/make -- OK
Running make test
PERL_DL_NONLAZY=1 "/usr/local/Cellar/perl/5.24.1/bin/perl" "-MExtUtils::Command::MM" "-MTest::Harness" "-e" "undef *Test::Harness::Switches; test_harness(0, 'blib/lib', 'blib/arch')" t/*.t
t/bad_variables.t ...... ok
t/carp-mismatch.t ...... ok
t/classmethod.t ........ ok
t/coderefs_in_inc.t .... ok
t/de-dup.t ............. ok
t/lib-core-only.t ...... ok
t/pipeline.t ........... ok
t/shell.t .............. ok
t/stackable.t .......... ok
t/subroutine-in-inc.t .. ok
t/taint-mode.t ......... ok
All tests successful.
Files=11, Tests=221,  3 wallclock secs ( 0.06 usr  0.03 sys +  2.21 cusr  0.88 csys =  3.18 CPU)
Result: PASS
  HAARG/local-lib-2.000019.tar.gz
  /usr/bin/make test -- OK
Running make install
Manifying 4 pod documents
Installing /Users/xyz/perl5/lib/perl5/lib/core/only.pm
Installing /Users/xyz/perl5/lib/perl5/local/lib.pm
Installing /Users/xyz/perl5/lib/perl5/POD2/DE/local/lib.pod
Installing /Users/xyz/perl5/lib/perl5/POD2/PT_BR/local/lib.pod
Installing /Users/xyz/perl5/man/man3/lib::core::only.3
Installing /Users/xyz/perl5/man/man3/local::lib.3
Installing /Users/xyz/perl5/man/man3/POD2::DE::local::lib.3
Installing /Users/xyz/perl5/man/man3/POD2::PT_BR::local::lib.3
Appending installation info to /Users/xyz/perl5/lib/perl5/darwin-thread-multi-2level/perllocal.pod
  HAARG/local-lib-2.000019.tar.gz
  /usr/bin/make install  -- OK

[DomT4]

Apologies, I left my comment without refreshing first & didn't realise @JCount had made it perfectly redundant 😄.

[iokill]

@DomT4 @JCount @dunn I'm sorry! Looks like i messed that up 😕

I just did a fresh install of perl and it works as expected without requiring sudo for PERL_MM_OPT="INSTALL_BASE=$HOME/perl5" cpan local::lib. Consequently, everything works as stated in the caveat then.

I was sure I did a fresh install before reporting this, but it turns out that I must have missed that somehow.

Thanks!

[DomT4]

No worries, thanks for letting us know. Given I wrote most of the perl formula colour me relieved you didn't find breakage 😸.