So, the answer is no ...

Yeah ... I was looking for a way of ensuring that whenever perl was run, then a specific module would be loaded before all other modules.
I was hoping that loading that module at the beginning of perl5opt would achieve that end, but now I see that alone is not guaranteed to work.

Actually, I was just wanting Test/Builder.pm to load Math/Ryu.pm (if Math::Ryu was installed).
The usual way to do that would be to have Builder.pm do eval{require Math::Ryu} but that causes t/Legacy/dont_overwrite_die_handler.t to fail a test (in the Test::Simple test suite) if Math::Ryu was not found.
Seems a funny thing to be causing a test to fail - but if they're testing for it, then one assumes it's important. (Shrug.)

So the next approach was to have Builder.pm check whether "Math/Ryu.pm" was in %INC ... and that's where it became important that Math::Ryu (if available) was loaded before Test::Builder.
Maybe that can be done simply enough ... but there's a few "what-ifs" to process when thinking through that.

And it's just an exercise that's not really going to lead anywhere.
Test::More can throw out some really stupid and irritating diagnostics like: 
>perl -MTest::More -le "cmp_ok(0.1 ** 2, '==', 0.01, 'T1'); done_testi
+ng();"
not ok 1 - T1
#   Failed test 'T1'
#   at -e line 1.
#          got: 0.01
#     expected: 0.01
1..1
# Looks like you failed 1 test of 1.

[download]
So I've patched Test/Builder.pm to be (eg) capable of providing: 
>perl -MMath::Ryu -MTest::More -le "cmp_ok(0.1 ** 2, '==', 0.01, 'T1')
+; done_testing();"
not ok 1 - T1
#   Failed test 'T1'
#   at -e line 1.
#          got: 0.010000000000000002
#     expected: 0.01
1..1
# Looks like you failed 1 test of 1.

[download]
I'll submit a PR when (if) I get the detail of involving Math::Ryu reliably sorted out.
But this irritating Test::More behaviour crops up only rarely, and no-one cares about it, anyway.

hippo, thanks for digging up the documentation.

Cheers,
Rob

In reply to Re^2: Unexpected behaviour with PERL5OPT by syphilis
in thread Unexpected behaviour with PERL5OPT by syphilis

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