0_problem.md

is:

make p-install && RAKUDO_MODULE_DEBUG=1 perl6-p -e 'use Test; say GLOBAL::'
MODULE_DEBUG: loading blib/Perl6/BOOTSTRAP.pbc
MODULE_DEBUG: done loading blib/Perl6/BOOTSTRAP.pbc

%chosen is:
key => /home/froggs/dev/nqp/install/lib/parrot/5.9.0-devel/languages/perl6/lib/Test.pm
pm => /home/froggs/dev/nqp/install/lib/parrot/5.9.0-devel/languages/perl6/lib/Test.pm
load => /home/froggs/dev/nqp/install/lib/parrot/5.9.0-devel/languages/perl6/lib/Test.pir

MODULE_DEBUG: loading [...]/parrot/5.9.0-devel/languages/perl6/lib/Test.pir
MODULE_DEBUG: done loading [...]/parrot/5.9.0-devel/languages/perl6/lib/Test.pir
().hash

but should be:

make p-install && RAKUDO_MODULE_DEBUG=1 perl6-p -e 'use Test; say GLOBAL::'
MODULE_DEBUG: loading blib/Perl6/BOOTSTRAP.pbc
MODULE_DEBUG: done loading blib/Perl6/BOOTSTRAP.pbc

%chosen is:
key => /home/froggs/dev/nqp/install/lib/parrot/5.9.0-devel/languages/perl6/lib/Test.pm
pm => /home/froggs/dev/nqp/install/lib/parrot/5.9.0-devel/languages/perl6/lib/Test.pm
load => /home/froggs/dev/nqp/install/lib/parrot/5.9.0-devel/languages/perl6/lib/Test.pir
ver => *

MODULE_DEBUG: loading [...]/parrot/5.9.0-devel/languages/perl6/lib/Test.pir
MODULE_DEBUG: done loading [...]/parrot/5.9.0-devel/languages/perl6/lib/Test.pir
("Test" => Test).hash

CompUnitRepo-Local-File.pm

class CompUnitRepo::Local::File {
    has @!paths;
    method new( *@location ) {
        self.bless(:@location)
    }

    method BUILD( :@location ) {
        @!paths = @location;
        self
    }

    method install( $source, $from? ) {
        ...
    }

    method candidates( $longname, :$file, :$auth, :$ver ) {
        my @candi;
        my Mu $c := nqp::gethllsym('perl6', 'ModuleLoader').p6ml.locate_candidates(
            $longname, nqp::p6listitems(nqp::decont([ @!paths, @*INC ])), :$file);
        if $c[0] {
            $c[0]<ver> = Version.new( '*' );
            @candi.push: $c[0].item;
        }
        @candi
    }
}

compunitrepo.diff

diff --git a/src/core/core_epilogue.pm b/src/core/core_epilogue.pm
index 96e75af..5b1cf96 100644
--- a/src/core/core_epilogue.pm
+++ b/src/core/core_epilogue.pm
@@ -14,4 +14,40 @@ BEGIN {
     Perl6::Metamodel::GrammarHOW.HOW.compose(Perl6::Metamodel::GrammarHOW);
 }
 
+my $prefix = ($*VM<properties><perl6.prefix> // $*VM<config><prefix>);
+if "$prefix/share/libraries.cfg".IO.e {
+    my @lines = slurp("$prefix/share/libraries.cfg").lines;
+    my %repos;
+    for @lines -> $repo {
+        next if $repo ~~ /^ '#'/;
+        if $repo ~~ / $<class>=[ <.ident>+ % '::' ] [ ':name<' $<libname>=\w+ '>' ]? '=' $<path>=.+ / {
+            my $libname = $<libname> // '';
+            %repos{~$<class>}{$libname} //= [];
+            %repos{~$<class>}{$libname}.push($<path>.IO.path.is-relative ?? "$prefix/share/$<path>" !! ~$<path>);
+        }
+    }
+    my @custom_libs = %*CUSTOM_LIB.values;
+    for %repos.kv -> $classname, $libnames {
+        for $libnames.kv -> $libname, $args {
+            if $classname eq 'CompUnitRepo::Local::File' {
+                CompUnitRepo.add_repo( CompUnitRepo::Local::File.new(|@$args), :name($libname) );
+            }
+            elsif $classname eq 'CompUnitRepo::Local::Installation' {
+                CompUnitRepo.add_repo( CompUnitRepo::Local::Installation.new(|@$args), :name($libname) );
+            }
+            else {
+                my $name = 'lib/' ~ $classname.split('::').join('/') ~ '.pm';
+                for @custom_libs -> $path {
+                    if "$path/$name".IO.e {
+                        require "$path/$name";
+                        CompUnitRepo.add_repo( ::($classname).new(|@$args), :name($libname) );
+                    }
+                }
+            }
+        }
+    }
+}
+
+nqp::bindhllsym('perl6', 'ModuleLoader', CompUnitRepo);
+
 {YOU_ARE_HERE}
diff --git a/tools/build/Makefile-Parrot.in b/tools/build/Makefile-Parrot.in
index c6a6a0b..0c00dfd 100644
--- a/tools/build/Makefile-Parrot.in
+++ b/tools/build/Makefile-Parrot.in
@@ -239,6 +239,10 @@ P_CORE_SOURCES = \
   src/core/terms.pm \
   src/core/Deprecations.pm \
   src/core/OS.pm \
+  src/core/JSON/Pretty.pm \
+  src/core/CompUnitRepo.pm \
+  src/core/CompUnitRepo/Local/File.pm \
+  src/core/CompUnitRepo/Local/Installation.pm \
   src/core/core_epilogue.pm \
 
 DOCS = README CREDITS LICENSE docs/*

CompUnitRepo.pm

class CompUnitRepo {
    my Mu $p6ml := nqp::gethllsym('perl6', 'ModuleLoader');
    my @repos;

    method candidates($longname, :$file, :$auth, :$ver) {
        my @candi;
        for @repos {
            @candi := (@candi, .candidates($longname, :$file, :$auth, :$ver)).flat
        }
        @candi.sort: { $^b<ver> cmp $^a<ver> }
    }

    method add_repo($repo, :$name) {
        @repos.push: $repo;
        %*CUSTOM_LIB{$name} := $repo if $name
    }

    method p6ml { $p6ml }

    method load_module($module_name, %opts, *@GLOBALish, :$line, :$file) {
        my $chosen = self.candidates($module_name, :auth(%opts<auth>), :ver(%opts<ver>))[0];
        $p6ml.load_module($module_name, %opts, @GLOBALish, :$line, :$file, :$chosen);
    }

    method ctxsave() { $p6ml.ctxsave() }
    method absolute_path($path) { $p6ml.absolute_path($path) }
    method load_setting($setting_name) { $p6ml.load_setting($setting_name) }
    method resolve_repossession_conflicts(@conflicts) { $p6ml.resolve_repossession_conflicts(@conflicts) }
}