Think ive got it working

lib/Module.pm

@@ -6,6 +6,7 @@ use Module::CoreList;
 use Storable;
 use IPC::Run qw/run/;
 no warnings 'experimental';
+use Carp qw/croak carp cluck confess/;
 
 has 'name' => (is => 'ro');
 has 'dist' => (is => 'ro',
@@ -25,6 +26,8 @@ sub _get_dist {
 }
 
 our %cache;
+our %rev_depcache;
+
 if (-e 'modcache.stor') {
     eval {
       my $cache_href=retrieve('modcache.stor');
@@ -34,17 +37,29 @@ if (-e 'modcache.stor') {
         print STDERR "Couldn't load cache $@\n";
     }
 }
+if (-e 'revdepcache.stor') {
+    eval {
+      my $cache_href=retrieve('revdepcache.stor');
+      %rev_depcache = $cache_href->%*;
+    };
+    if ($@) {
+        print STDERR "Couldn't load cache $@\n";
+    }
+}
 
 sub __save_cache {
  store \%cache, 'modcache.stor';
+ store \%rev_depcache, 'revdepcache.stor';
 };
 END {__save_cache};
 
 sub new_module {
     my $class = shift;
     my $module = shift;
+    confess "\n\nNo module name given\n" unless $module;
     my ($name, $version) = split (/[\-~]/, $module);
 
+
     my $dist = $Dist::mod_to_dist{$name} // $name;
 
     return $cache{$dist} if exists $cache{$dist};
@@ -106,4 +121,52 @@ sub _print_deps {
     }
 }
 
+sub depends_on {
+  my ($self, $module) = @_;
+
+  my $dist = $module->_get_dist();
+
+  for my $dep ($self->depends->@*) {
+    return 1 if $dep->_get_dist eq $dist;
+  }
+
+  return 0;
+}
+
+# Look at all failed modules, see if they might have depended on us.
+sub get_failed_descendants {
+  my $self = shift;
+  my $candidates = shift;
+  my $level = shift || 0;
+  my $loop = shift || [];
+
+  my $sdist = $self->_get_dist;
+  if (grep {$_->_get_dist eq $sdist} @$loop) {
+    print "Loop detected with ", $self->name, ".  Short circuiting\n";
+    return();
+  }
+
+
+  if (ref($rev_depcache{$self->name}) eq 'ARRAY') {
+    return $rev_depcache{$self->name}->@*;
+  }
+
+  my @total;
+
+  my $c=1;
+  for my $mod_name (@$candidates) {
+    printf "%03d %05d\r", $level, $c++;
+    my $module = Module->new_module($mod_name);
+
+    if ($module->depends_on($self)) {
+      push @total, $module->get_failed_descendants($candidates, $level+1, [@$loop, $self]);
+    }
+  }
+
+  print "\n";
+
+  $rev_depcache{$self->name} = \@total;
+  return @total;
+}
+
 1;

statfailures.pl

@@ -0,0 +1,31 @@
+#!/usr/bin/env perl
+
+use 5.24.0;
+
+use strict;
+use warnings;
+use lib './lib';
+
+use Module;
+use Dist;
+use Storable qw/retrieve/;
+use Data::Dumper;
+
+my $data = retrieve 'everything.stor';
+
+my @failed_list = grep {$data->{jobstatus}{$_}{status} ne 'success'} grep {defined $_ && $_ ne ''} keys($data->{jobstatus}->%*);
+
+my %mods;
+
+LOOP: for my $mod ($data->{modules}->@*) {
+  my $status = $data->{jobstatus}{$mod}{status} // "";
+
+  if ($status ne 'success') {
+    print "DEP Checking $mod\n";
+    my $module = Module->new_module($mod);
+    my @dependedonby = $module->get_failed_descendants(\@failed_list);
+
+    $mods{$mod} = \@dependedonby;
+    print Dumper(\@dependedonby);
+  }
+}