Explicitly reject length(NAME) with typemaps other than T_PV

Previously, the length operator on typemaps other than T_PV would lead
to that length value not being initialized, leading to segfaults and
worse. Worse yet, parsexs would silently emit this erroneous code.

For now it will at least give a clear error, in the future we should
perhaps consider eliminating this limitation altogether.

Author: Leont

dist/ExtUtils-ParseXS/Changes

@@ -1,5 +1,9 @@
 Revision history for Perl extension ExtUtils::ParseXS.
 
+3.59
+  - Throw an exception when combining the length operator with a
+    typemap other than T_PV
+
 3.58 Sun Jul 20 09:10:41 PM CEST 2025
   - ExtUtils::ParseXS has been extensively restructured internally.
     Most of these changes shouldn't be visible externally, but might

dist/ExtUtils-ParseXS/lib/ExtUtils/ParseXS/Node.pm

@@ -1407,7 +1407,9 @@ sub lookup_input_typemap {
         # as a pseudo-parameter, then override the normal typedef - which
         # would emit SvPV_nolen(...) - and instead, emit SvPV(...,
         # STRLEN_length_of_foo)
-        if ($xstype eq 'T_PV' and $self->{has_length}) {
+        if ($self->{has_length}) {
+            die "length(NAME) not supported with typemaps other than T_PV"
+                if $xstype ne 'T_PV';
             die "default value not supported with length(NAME) supplied"
                 if defined $default;
             return "($type)SvPV($arg, STRLEN_length_of_$var);",

dist/ExtUtils-ParseXS/t/001-basic.t

@@ -967,7 +967,7 @@ EOF
         |
         |int
         |foo(  a   ,  char   * b  , OUT  int  c  ,  OUTLIST int  d   ,    \
-        |      IN_OUT char * * e    =   1  + 2 ,   long length(e)   ,    \
+        |      IN_OUT char * * e    =   1  + 2 ,   long length(b)   ,    \
         |      char* f="abc"  ,     g  =   0  ,   ...     )
 EOF
 
@@ -1607,6 +1607,13 @@ EOF
             [ 1, 0, qr{\QError: length() on non-parameter 's'\E.*line 6},
                    "got expected error" ],
         ],
+
+		[
+			'length of int is invalid',
+			['int', 'foo(int a, size_t length(a))'],
+			[ 1, 0 , qr/length\(NAME\) not supported with typemaps other than T_PV/, 'Got expected error about length' ],
+		],
+
     );
 
     test_many($preamble, 'XS_Foo_', \@test_fns);