Hello monks,

I have a module using Module::Build. There is one test file that is failing under 'Build test' but does not fail under 'perl -Mblib <test_file>'. My print debugging was showing identical things happening during test in both cases, so I decided to run under the debugger and have a look.

I found that while I could insert breakpoints when running via 'perl -d -Mblib <test_file>', the same breakpoints would not stop execution while running under 'perl -d Build test'.

Here's some simple code showing the issue I'm seeing:

#pm file
package BPTest;
use strict;
use warnings;

sub do_stuff {
    $DB::single = 1;
    my $x = 10;
    return $x;
}

1;

#test file
use Test::More tests => 2;

BEGIN { use_ok( 'BPTest' ); }

is(
  BPTest->do_stuff,
  10,
  'do_stuff returns 10'
)
[download]

Here is what happens under 'perl -Mblib <test_file>':

plxc16479> perl -d -Mblib t/001_load.t

Loading DB routines from perl5db.pl version 1.33
Editor support available.

Enter h or `h h' for help, or `man perldebug' for more help.

1..2
ok 1 - use BPTest;
main::(t/001_load.t:9): is(
main::(t/001_load.t:10):          BPTest->do_stuff,
main::(t/001_load.t:11):          10,
main::(t/001_load.t:12):          'do_stuff returns 10'
main::(t/001_load.t:13):        )
  DB<1> c                                                             
+                                  
BPTest::do_stuff(/nfs/pdx/disks/nehalem.pde.077/tmp/BPTest/blib/lib/BP
+Test.pm:7):
7:          my $x = 10;
  DB<1>
[download]

I'm stopped at my breakpoint like I expect. Here's what happens under 'perl -d Build test':

plxc16479> perl -d Build test

Loading DB routines from perl5db.pl version 1.33
Editor support available.

Enter h or `h h' for help, or `man perldebug' for more help.

main::(Build:17):       my $progname;
  DB<1> c                                                             
+                                  
t/001_load.t .. ok   
All tests successful.
Files=1, Tests=2,  0 wallclock secs ( 0.03 usr  0.00 sys +  0.02 cusr 
+ 0.00 csys =  0.05 CPU)
Result: PASS
Debugged program terminated.  Use q to quit or R to restart,
  use o inhibit_exit to avoid stopping after program termination,
  h q, h R or h o to get additional info.  
  DB<1>
[download]

Here I did not stop at the breakpoint. This is making debug difficult since the test failure only occurs under 'Build test'. I have tried to set the breakpoint from the debugger via 'b <sub_name>' and 'b <line>', but both are ignored the same as $DB::single.

So the questions: What is happening under 'Build test' that prevents breakpoints from being honored? At a higher level, what does 'Build test' do differently regarding test files as compared to 'perl -Mblib <file>'?

I appreciate the help and any time spent looking over my question :)

UPDATE: I have resolved the underlying problem causing the test failure. Turns out the @INC array was in a different order when executing 'Build test' vs 'perl -Mblib <test_file>' and was picking up a non test version of one of my modules. However, I'm still interested in why the breakpoints do not seem to work from Build test :)