How to install Perl on macOS 10.13 High Sierra

Question

I recently upgraded to macOS 10.13 High Sierra and shortly after encountered a problem attempting to install a more recent version of Perl (5.26.1). The gist of the problem is that the self-tests for cpan/DB_File consistently failed on macOS 10.13 High Sierra (home laptop) but succeeded on macOS 10.12 Sierra (work laptop).

Here's the section of the installation log showing the failure:

../cpan/Config-Perl-V/t/30_plv5240.t ............................... ok
../cpan/Config-Perl-V/t/31_plv52511.t .............................. ok
../cpan/DB_File/t/db-btree.t ....................................... ok
Use of uninitialized value $value in string eq at t/db-hash.t line 224.
Use of uninitialized value $values[0] in string eq at t/db-hash.t line 224.
Use of uninitialized value $value in lc at t/db-hash.t line 224.
Use of uninitialized value $h{""} in string eq at t/db-hash.t line 243.
Use of uninitialized value in numeric eq (==) at t/db-hash.t line 252.
Use of uninitialized value in numeric eq (==) at t/db-hash.t line 252.
Use of uninitialized value in numeric eq (==) at t/db-hash.t line 252.
Use of uninitialized value in numeric eq (==) at t/db-hash.t line 252.
Use of uninitialized value in numeric eq (==) at t/db-hash.t line 252.
Use of uninitialized value in numeric eq (==) at t/db-hash.t line 252.
Use of uninitialized value in numeric eq (==) at t/db-hash.t line 252.
Use of uninitialized value in numeric eq (==) at t/db-hash.t line 252.
Use of uninitialized value $foo[18] in join or string at t/db-hash.t line 261.
Use of uninitialized value $foo[36] in join or string at t/db-hash.t line 261.
Use of uninitialized value $foo[48] in join or string at t/db-hash.t line 261.
Use of uninitialized value $foo[58] in join or string at t/db-hash.t line 261.
Use of uninitialized value $foo[59] in join or string at t/db-hash.t line 261.
Use of uninitialized value $foo[60] in join or string at t/db-hash.t line 261.
Use of uninitialized value $foo[62] in join or string at t/db-hash.t line 261.
Use of uninitialized value $foo[63] in join or string at t/db-hash.t line 261.
Use of uninitialized value $foo[92] in join or string at t/db-hash.t line 261.
Use of uninitialized value $foo[114] in join or string at t/db-hash.t line 261.
Use of uninitialized value $foo[140] in join or string at t/db-hash.t line 261.
Use of uninitialized value $foo[187] in join or string at t/db-hash.t line 261.
Use of uninitialized value $foo[188] in join or string at t/db-hash.t line 261.
Use of uninitialized value $foo[189] in join or string at t/db-hash.t line 261.
Use of uninitialized value $h{"Fred"} in string eq at t/db-hash.t line 572.
Use of uninitialized value $v in concatenation (.) or string at t/db-hash.t line 748.
../cpan/DB_File/t/db-hash.t ........................................ 
Dubious, test returned 2 (wstat 512, 0x200)
Failed 76/166 subtests 

I was able to repeat this same failure whether installing using perlbrew install perl-5.26.1 or simply downloading the Perl tarfile and installing manually. When I try to debug the test in question t/db-hash.t, I can see that the test hash %h is created and is being populated in the test file, but when I print Dumper(\%h) I see that the hash looks to have the right keys, but all of the values are undef, rather than the values being assigned in the test script.

These undef values are causing the test failure. Oddly, the undefined values show up when I print the whole hash or try to make an array of the hash values. If I ask for a specific hash key's value, e.g. my $value = $h{key}, the value prints fine.

Questions:

• How to fix this so that I can install a new Perl on macOS 10.13?
• What broke? This used to work on macOS 10.12.

Answer 1

To install perl itself (which contains the DB_File module), or to install the DB_File module from CPAN, the solution is the same: edit its config.in to point to the proper location of berkeley-db.

For example, I have installed the db48 package via macports with sudo port install db48. In the perl download itself, I navigate to cpan/DB_File and edit its config.in, changing the existing INCLUDE and LIB assignments thusly:

INCLUDE    = /opt/local/include/db48
LIB        = /opt/local/lib/db48

I can then resume the perl build process and DB_File can compile.

References:

Perl RT#133280
CPAN RT#125238

Answer 2

TL;DR

Here's what worked:

1. Install Berkeley DB. I use Homebrew, but you can get the source files at the Oracle site.

   brew install berkeley-db
   

2. Install Perl. I use Perlbrew, but you can get the source files at the Perl site.

   perlbrew install perl-5.26.1
   

---

A Partial Explanation

Looking back through the failed installation log, there is a warning near the DB_File sections that gives a clue:

...
./miniperl -Ilib make_ext.pl lib/auto/DB_File/DB_File.bundle  MAKE="/Applications/Xcode.app/Contents/Developer/usr/bin/make" LIBPERL_A=libperl.a LINKTYPE=dynamic
Parsing config.in...
Looks Good.
Warning (mostly harmless): No library found for -ldb
Generating a Unix-style Makefile
Writing Makefile for DB_File
...

No db library found, mostly harmless.

According to the docs for the DB_File module, it is...

... a module which allows Perl programs to make use of the facilities provided by Berkeley DB...

After installing berkeley-db, the same section of the Perl installation log no longer shows the same warning:

...
./miniperl -Ilib make_ext.pl lib/auto/DB_File/DB_File.bundle  MAKE="/Applications/Xcode.app/Contents/Developer/usr/bin/make" LIBPERL_A=libperl.a LINKTYPE=dynamic
Parsing config.in...
Looks Good.
Generating a Unix-style Makefile
Writing Makefile for DB_File
...

And further along the process, the previously failed tests pass, allowing installation to complete successfully:

...
../cpan/DB_File/t/db-btree.t ....................................... ok
../cpan/DB_File/t/db-hash.t ........................................ ok
../cpan/DB_File/t/db-recno.t ....................................... ok
...

I haven't been able to find any documentation online about why Berkeley DB appears to be missing from macOS 10.13 High Sierra, and whether that was a change from previous macOS versions, as it seems.

Many thanks to Tim D for helping me troubleshoot.