Summary
Sub::Quote 2.006009 fails when quoted/deferred subs are retrieved or invoked from PerlOnJava threads. The failure reproduces on both the JVM and interpreter backends.
Reproduction
The CPAN random tester record is:
2026-09-18 07:06:07 FAIL Sub::Quote Sub::Defer ... 5430 5435 5/5435 subtests failed; 1/15 test programs failed
The failing test is:
Using the built distribution with its library and test-library paths:
timeout 120 ./jperl -I<build>/blib/lib -I<build>/t/lib <build>/t/sub-quote-threads.t
timeout 120 ./jperl --interpreter -I<build>/blib/lib -I<build>/t/lib <build>/t/sub-quote-threads.t
Both backends fail identically: 5 of 6 assertions fail. The only passing assertion is the unquoted One case. Quoted/deferred sub retrieval and execution return undef, including the two-thread cases.
The complete CPAN run has 14 of 15 test programs passing; only t/sub-quote-threads.t fails. PerlOnJava also emits:
Use of uninitialized value in hash element at .../Sub/Defer.pm line 75
Expected behavior
System Perl passes the complete oracle run: 7036/7036 tests, including t/sub-quote-threads.t.
Technical analysis
Sub::Defer::undefer_sub looks up deferred-sub metadata in %DEFERRED using the deferred sub reference. Sub::Defer provides a CLONE implementation specifically to repair stringified subreference keys after threading.
On PerlOnJava, the lookup at Sub/Defer.pm line 75 receives an undefined or otherwise non-matching key after the thread boundary. This indicates that thread cloning is not preserving or remapping the identity/metadata of deferred quoted subs as required by Sub::Defer::CLONE.
The issue is present in both execution backends, so it appears to be shared runtime/thread-cloning behavior rather than a JVM-backend-only problem or a module-specific compilation issue.
Impact
Non-threaded Sub::Quote functionality passes, but applications using quoted/deferred subs from Perl threads can silently receive undef or fail to invoke the intended subroutine. This is a compatibility bug affecting modules that use Sub::Quote together with threads.
Suggested investigation
- Trace cloning of the deferred sub reference and the
%DEFERRED metadata across thread creation.
- Compare PerlOnJava's handling of
CLONE and stringified subreference keys with system Perl.
- Add a focused project-owned regression test covering
quote_sub, quoted_from_sub, unquote_sub, and deferred-sub invocation from a child thread on both backends.
Summary
Sub::Quote2.006009 fails when quoted/deferred subs are retrieved or invoked from PerlOnJava threads. The failure reproduces on both the JVM and interpreter backends.Reproduction
The CPAN random tester record is:
The failing test is:
Using the built distribution with its library and test-library paths:
Both backends fail identically: 5 of 6 assertions fail. The only passing assertion is the unquoted
Onecase. Quoted/deferred sub retrieval and execution returnundef, including the two-thread cases.The complete CPAN run has 14 of 15 test programs passing; only
t/sub-quote-threads.tfails. PerlOnJava also emits:Expected behavior
System Perl passes the complete oracle run: 7036/7036 tests, including
t/sub-quote-threads.t.Technical analysis
Sub::Defer::undefer_sublooks up deferred-sub metadata in%DEFERREDusing the deferred sub reference.Sub::Deferprovides aCLONEimplementation specifically to repair stringified subreference keys after threading.On PerlOnJava, the lookup at
Sub/Defer.pmline 75 receives an undefined or otherwise non-matching key after the thread boundary. This indicates that thread cloning is not preserving or remapping the identity/metadata of deferred quoted subs as required bySub::Defer::CLONE.The issue is present in both execution backends, so it appears to be shared runtime/thread-cloning behavior rather than a JVM-backend-only problem or a module-specific compilation issue.
Impact
Non-threaded
Sub::Quotefunctionality passes, but applications using quoted/deferred subs from Perl threads can silently receiveundefor fail to invoke the intended subroutine. This is a compatibility bug affecting modules that useSub::Quotetogether withthreads.Suggested investigation
%DEFERREDmetadata across thread creation.CLONEand stringified subreference keys with system Perl.quote_sub,quoted_from_sub,unquote_sub, and deferred-sub invocation from a child thread on both backends.