Replace "grandfather in ..." with a full description of the change

Unrecognised characters in pack/unpack formats were made fatal in 5.004,
with an exception added in 5.004_04 for ',' to "just" warn.

Add tests that the format with the comma behaves the same as a format
without.

2 files changed, 7 insertions, 2 deletions

diff --git a/pp_pack.c b/pp_pack.c
index 60cbfa529b..b64d911be7 100644
--- a/pp_pack.c
+++ b/pp_pack.c
@@ -611,7 +611,9 @@ S_next_symbol(pTHX_ tempsym_t* symptr )
       I32 code = (U8) *patptr++;
       U32 inherited_modifiers = 0;
 
-      if (code == ','){ /* grandfather in commas but with a warning */
+      /* unrecognised characters in pack/unpack formats were made fatal in
+       * 5.004, with an exception added in 5.004_04 for ',' to "just" warn: */
+      if (code == ','){
         if (((symptr->flags & FLAG_COMMA) == 0) && ckWARN(WARN_UNPACK)){
           symptr->flags |= FLAG_COMMA;
           Perl_warner(aTHX_ packWARN(WARN_UNPACK),
diff --git a/t/op/pack.t b/t/op/pack.t
index bfcfc6cd91..376f58e71f 100644
--- a/t/op/pack.t
+++ b/t/op/pack.t
@@ -6,7 +6,7 @@ BEGIN {
     set_up_inc(qw '../lib ../dist/Math-BigInt/lib');
 }
 
-plan tests => 14718;
+plan tests => 14720;
 
 use strict;
 use warnings qw(FATAL all);
@@ -1230,11 +1230,14 @@ is(pack('L<L>', (0x12345678)x2),
   @warning = ();
   my $x = pack( 'I,A', 4, 'X' );
   like( $warning[0], qr{Invalid type ','} );
+  is($x, pack( 'IA', 4, 'X' ), "Comma was ignored in pack string");
 
   # comma warning only once
   @warning = ();
   $x = pack( 'C(C,C)C,C', 65..71  );
   cmp_ok( scalar(@warning), '==', 1 );
+  is(join(",", unpack 'C(C,,,C),C,,C', $x), join(",", 65..69),
+     "Comma was ignored in unpack string");
 
   # forbidden code in []
   eval { my $x = pack( 'A[@4]', 'XXXX' ); };