[perl #48489] patch to fix perl bug #7013

From: "bharanee rathna" (via RT) <perlbug-followup@perl.org>
Message-ID: <rt-3.6.HEAD-28750-1197415521-1978.48489-75-0@perl.org>

Just the pp_hot.c portion of this patch applied along with removing
the TODO from the test added in the previous change.

p4raw-id: //depot/perl@34833

lib/perl5db.t

@@ -76,9 +76,8 @@ like($contents, qr/sub factorial/,
     'The ${main::_<filename} variable in the debugger was not destroyed'
 );
 
-TODO: {
+{
     local $ENV{PERLDB_OPTS} = "ReadLine=0";
-    local $::TODO = "lvalueness isn't propagated in the debugger";
     my $output = runperl(switches => [ '-d' ], progfile => '../lib/perl5db/t/lvalue-bug');
     like($output, qr/foo is defined/, 'lvalue subs work in the debugger');
 }

pp_hot.c

@@ -2774,7 +2774,14 @@ PP(pp_entersub)
 	 Perl_get_db_sub(aTHX_ &sv, cv);
 	 if (CvISXSUB(cv))
 	     PL_curcopdb = PL_curcop;
-	 cv = GvCV(PL_DBsub);
+         if (CvLVALUE(cv)) {
+             /* check for lsub that handles lvalue subroutines */
+	     cv = GvCV(gv_HVadd(gv_fetchpv("DB::lsub", GV_ADDMULTI, SVt_PVHV)));
+             /* if lsub not found then fall back to DB::sub */
+	     if (!cv) cv = GvCV(PL_DBsub);
+         } else {
+             cv = GvCV(PL_DBsub);
+         }
 
 	if (!cv || (!CvXSUB(cv) && !CvSTART(cv)))
 	    DIE(aTHX_ "No DB::sub routine defined");