fix: support experimental warnings and Sub::Import detection

dev/design/issue-queue.md

@@ -37,7 +37,8 @@ resolved before implementation. No new pass or failure is asserted here.
 | Calls and value operations | [#1448](https://github.com/fglock/PerlOnJava/issues/1448) Audit-wrapper recursion | High / Investigate | Runaway recursion on both backends with a passing Perl suite. Trace captured original coderef identity and wrapper replacement under a timeout; no proven #1649 dependency. |
 | Calls and value operations | [#1342](https://github.com/fglock/PerlOnJava/issues/1342) Relational overload dispatch | Normal / Ready | Report identifies an unwanted `cmp` dispatch. Add direct relational-overload coverage and require Morpheus acceptance on both backends. |
 | Calls and value operations | [#1428](https://github.com/fglock/PerlOnJava/issues/1428) Decimal stringification | Normal / Ready | One DateTime::Format::Epoch mismatch with passing Perl suite. Reduce the numeric conversion and cover large integral results without scientific notation. |
-| Warnings category tables | [#1208](https://github.com/fglock/PerlOnJava/issues/1208), [#1219](https://github.com/fglock/PerlOnJava/issues/1219) Experimental categories | Normal / Ready | Unknown valid categories prevent module load. Check shared registration code, add category-specific focused tests and upstream load acceptance; batch only if one registration mechanism owns both. |
+| Warning category tables | [#1208](https://github.com/fglock/PerlOnJava/issues/1208), [#1219](https://github.com/fglock/PerlOnJava/issues/1219) Experimental categories | Normal / Active | Bundled Perl 5.44 warning-category and bit-mask compatibility; focused coverage and both-backend acceptance are in progress. [Current claim](https://github.com/fglock/PerlOnJava/issues/1208#issuecomment-6524996715). |
+| B subroutine introspection | [#1206](https://github.com/fglock/PerlOnJava/issues/1206) Sub::Import detection | Normal / Active | Reproduced the upstream `Sub::Import` 1.002 `t/import-se.t` failure; preserve the start-op stash used to identify Sub::Exporter importers. [Current claim](https://github.com/fglock/PerlOnJava/issues/1206#issuecomment-6524997331). |
 | Regex matcher performance | [#1174](https://github.com/fglock/PerlOnJava/issues/1174) Anchored full match | High / Investigate | Reported 475–550x gap has a bounded workload. Reproduce/profile exact source and JAR, then define semantics-preserving engine coverage. No ownership rewrite prerequisite is established. |
 | Call-path measurement | [#1885](https://github.com/fglock/PerlOnJava/issues/1885) Memory and ordinary calls | Normal / Investigate | Follow up #1870 with matched allocation/live-heap/RSS and general-call evidence. Coordinate any frame/argument ownership edits with #1649; measurements alone can proceed. |
 | Call-path measurement | [#1863](https://github.com/fglock/PerlOnJava/issues/1863) Throughput acceptance | Normal / Verify | Portfolio targets are reported met by #1870. Reconcile merged-source evidence and remaining criteria with #1885 before scheduling more optimizations. |

docs/about/changelog.md

@@ -6,6 +6,8 @@ priorities and future plans.
 
 ## Work in progress
 
+- Accept `experimental::for_list` as Perl 5.44's no-op warning category, align bundled warning masks including `experimental::builtin`, and expose B start-op package identity for Sub::Import compatibility (#1208, #1219, #1206).
+
 - Preserve the input line number when a borrowed anonymous filehandle alias leaves a JVM subroutine scope (#1933).
 
 - Resolve glob-backed filehandles in `POSIX::isatty` without assuming the glob value is a `RuntimeIO` (#1932).

src/main/java/org/perlonjava/runtime/runtimetypes/WarningFlags.java

@@ -30,7 +30,7 @@ private static CompilationRuntimeState state() {
         // Initialize the hierarchy of warning categories
         warningHierarchy.put("all", new String[]{"closure", "deprecated", "exiting", "experimental", "glob", "imprecision", "io", "locale", "misc", "missing", "missing_import", "numeric", "once", "overflow", "pack", "portable", "recursion", "redefine", "redundant", "regexp", "scalar", "severe", "shadow", "signal", "substr", "syntax", "taint", "threads", "uninitialized", "unpack", "untie", "utf8", "void", "__future_81", "__future_82", "__future_83"});
         warningHierarchy.put("deprecated", new String[]{"deprecated::apostrophe_as_package_separator", "deprecated::delimiter_will_be_paired", "deprecated::dot_in_inc", "deprecated::goto_construct", "deprecated::missing_import_called_with_args", "deprecated::smartmatch", "deprecated::subsequent_use_version", "deprecated::unicode_property_name", "deprecated::version_downgrade"});
-        warningHierarchy.put("experimental", new String[]{"experimental::alpha_assertions", "experimental::args_array_with_signatures", "experimental::bitwise", "experimental::builtin", "experimental::class", "experimental::declared_refs", "experimental::defer", "experimental::enhanced_xx", "experimental::extra_paired_delimiters", "experimental::isa", "experimental::postderef", "experimental::private_use", "experimental::re_strict", "experimental::refaliasing", "experimental::regex_sets", "experimental::script_run", "experimental::signatures", "experimental::smartmatch", "experimental::try", "experimental::uniprop_wildcards", "experimental::vlb", "experimental::keyword_any", "experimental::keyword_all", "experimental::lexical_subs", "experimental::signature_named_parameters", "experimental::equ"});
+        warningHierarchy.put("experimental", new String[]{"experimental::alpha_assertions", "experimental::args_array_with_signatures", "experimental::bitwise", "experimental::builtin", "experimental::class", "experimental::declared_refs", "experimental::defer", "experimental::enhanced_xx", "experimental::extra_paired_delimiters", "experimental::for_list", "experimental::isa", "experimental::postderef", "experimental::private_use", "experimental::re_strict", "experimental::refaliasing", "experimental::regex_sets", "experimental::script_run", "experimental::signatures", "experimental::smartmatch", "experimental::try", "experimental::uniprop_wildcards", "experimental::vlb", "experimental::keyword_any", "experimental::keyword_all", "experimental::lexical_subs", "experimental::signature_named_parameters", "experimental::equ"});
         warningHierarchy.put("io", new String[]{"io::closed", "io::exec", "io::layer", "io::newline", "io::pipe", "io::syscalls", "io::unopened"});
         warningHierarchy.put("severe", new String[]{"severe::debugging", "severe::inplace", "severe::internal", "severe::malloc"});
         warningHierarchy.put("syntax", new String[]{"syntax::ambiguous", "syntax::bareword", "syntax::digit", "syntax::illegalproto", "syntax::parenthesis", "syntax::precedence", "syntax::printf", "syntax::prototype", "syntax::qw", "syntax::reserved", "syntax::semicolon"});

src/main/perl/lib/B.pm

@@ -247,7 +247,8 @@ package B::CV {
                 $file ||= "-e";
                 $line ||= 0;
                 if ($line > 0) {
-                    return B::COP->new($file, $line);
+                    $self->_introspect;
+                    return B::COP->new($file, $line, $self->{_pkg_name});
                 }
             }
         }
@@ -472,8 +473,12 @@ package B::COP {
     our @ISA = ('B::OP');
 
     sub new {
-        my ($class, $file, $line) = @_;
-        return bless { file => $file // "-e", line => $line // 0 }, $class;
+        my ($class, $file, $line, $stash) = @_;
+        return bless {
+            file => $file // "-e",
+            line => $line // 0,
+            stash => $stash // 'main',
+        }, $class;
     }
 
     sub file {
@@ -486,6 +491,11 @@ package B::COP {
         return $self->{line};
     }
 
+    sub stashpv {
+        my $self = shift;
+        return $self->{stash};
+    }
+
     sub next {
         return B::NULL->new();
     }

src/main/perl/lib/warnings.pm

@@ -71,42 +71,43 @@ our %Offsets = (
     'non_unicode'			=> 100,
     'nonchar'				=> 102,
     'surrogate'				=> 104,
-    'experimental'			=> 106,
+    'experimental'	=> 104,
     # Retired experimental categories share the parent bit so old source can
     # continue to query and suppress them after the features became stable.
-    'experimental::alpha_assertions'	=> 106,
-    'experimental::isa'			=> 106,
+    'experimental::alpha_assertions'	=> 104,
+    'experimental::isa'	=> 104,
     # Compatibility alias used by code targeting Perl 5.20-5.24. Postfix
     # dereferencing is stable now, but old sources still disable its warning.
-    'experimental::postderef'		=> 106,
-    'experimental::regex_sets'		=> 108,
-    'syscalls'				=> 110,
-    'experimental::re_strict'		=> 112,
-    'experimental::refaliasing'		=> 114,
-    'locale'				=> 116,
-    'missing'				=> 118,
-    'redundant'				=> 120,
-    'experimental::declared_refs'	=> 122,
-    'deprecated::dot_in_inc'		=> 124,
-    'shadow'				=> 126,
-    'experimental::private_use'		=> 128,
-    'experimental::uniprop_wildcards'	=> 130,
-    'experimental::vlb'			=> 132,
-    'experimental::try'			=> 134,
-    'experimental::args_array_with_signatures'=> 136,
-    'experimental::builtin'		=> 138,
-    'experimental::defer'		=> 140,
-    'experimental::extra_paired_delimiters'=> 142,
-    'scalar'				=> 144,
-    'deprecated::version_downgrade'	=> 146,
-    'deprecated::delimiter_will_be_paired'=> 148,
-    'experimental::class'		=> 150,
-    'deprecated::missing_import_called_with_args'=> 152,
-    'deprecated::subsequent_use_version'=> 154,
-    'experimental::keyword_all'		=> 156,
-    'experimental::keyword_any'		=> 158,
-    'experimental::bitwise'		=> 160,
+    'experimental::postderef'	=> 104,
+    'experimental::regex_sets'	=> 106,
+    'syscalls'	=> 108,
+    'experimental::re_strict'	=> 110,
+    'experimental::refaliasing'	=> 112,
+    'locale'	=> 114,
+    'missing'	=> 116,
+    'redundant'	=> 118,
+    'experimental::declared_refs'	=> 120,
+    'deprecated::dot_in_inc'	=> 122,
+    'shadow'	=> 124,
+    'experimental::private_use'	=> 126,
+    'experimental::uniprop_wildcards'	=> 128,
+    'experimental::vlb'	=> 130,
+    'experimental::try'	=> 132,
+    'experimental::args_array_with_signatures'	=> 134,
+    'experimental::builtin'	=> 136,
+    'experimental::defer'	=> 138,
+    'experimental::extra_paired_delimiters'	=> 140,
+    'scalar'	=> 142,
+    'deprecated::version_downgrade'	=> 144,
+    'deprecated::delimiter_will_be_paired'	=> 146,
+    'experimental::class'	=> 148,
+    'deprecated::subsequent_use_version'	=> 150,
+    'experimental::keyword_all'	=> 152,
+    'experimental::keyword_any'	=> 154,
     'experimental::equ'			=> 162,
+    'experimental::enhanced_xx'	=> 156,
+    'experimental::signature_named_parameters'	=> 158,
+    'missing_import'	=> 160,
 );
 
 # Warning category masks - public compatibility data used by modules such as
@@ -164,7 +165,13 @@ our %Bits     = map { $_ => _mk_warning_mask(0, $_) } keys %Offsets;
 our %DeadBits = map { $_ => _mk_warning_mask(1, $_) } keys %Offsets;
 
 # NoOp warnings - warnings that have been removed but kept for compatibility
-our %NoOp = ();
+our %NoOp = map { $_ => 1 } qw(
+    deprecated::goto_construct deprecated::missing_import_called_with_args
+    deprecated::smartmatch experimental::alpha_assertions experimental::bitwise
+    experimental::const_attr experimental::for_list experimental::isa
+    experimental::lexical_subs experimental::postderef experimental::script_run
+    experimental::signatures experimental::smartmatch
+);
 
 sub register_categories (;@) {
     # placeholder

src/test/resources/unit/sub_import_sub_exporter_detection.t

@@ -0,0 +1,23 @@
+use strict;
+use warnings;
+use Test::More;
+use B qw(svref_2object);
+use Sub::Exporter;
+
+{
+    package ImportViaSubExporter;
+    use Sub::Exporter -setup => {
+        exports => [qw(foo)],
+    };
+
+    sub foo { 'FOO' }
+}
+
+my $importer = ImportViaSubExporter->can('import');
+is(svref_2object($importer)->START->stashpv, 'Sub::Exporter',
+    'B::CV START identifies the package that created a Sub::Exporter importer');
+
+$importer->('ImportViaSubExporter', foo => { -as => 'bar' });
+is(bar(), 'FOO', 'detected Sub::Exporter importer supports renamed imports');
+
+done_testing;

src/test/resources/unit/warnings_experimental_categories.t

@@ -0,0 +1,45 @@
+use strict;
+use warnings;
+use Test::More;
+
+sub warning_bits_at_call_site {
+    return (caller(0))[9];
+}
+
+{
+    use warnings 'experimental::for_list';
+    ok(defined warning_bits_at_call_site(),
+        'experimental::for_list is accepted by use warnings');
+}
+
+{
+    no warnings 'experimental::for_list';
+    pass('experimental::for_list is accepted by no warnings');
+}
+
+my $builtin_bits;
+{
+    use warnings 'experimental::builtin';
+    $builtin_bits = warning_bits_at_call_site();
+}
+ok(vec($builtin_bits, $warnings::Offsets{'experimental::builtin'}, 1),
+    'experimental::builtin sets its Perl warning bit');
+
+{
+    no warnings 'experimental::builtin';
+    $builtin_bits = warning_bits_at_call_site();
+}
+ok(!vec($builtin_bits, $warnings::Offsets{'experimental::builtin'}, 1),
+    'no warnings clears the experimental::builtin bit');
+
+{
+    use warnings FATAL => 'experimental::builtin';
+    $builtin_bits = warning_bits_at_call_site();
+}
+ok(vec($builtin_bits, $warnings::Offsets{'experimental::builtin'} + 1, 1),
+    'fatal experimental::builtin sets its fatal bit');
+
+require Data::Dumper;
+ok($Data::Dumper::VERSION, 'Data::Dumper loads with experimental::builtin declarations');
+
+done_testing;