Make bless(REF, REF) a fatal error, add bless tests.

Subject: [PATCH bleadperl-6530] bless, REF, and bless(REF, REF)
Message-Id: <200008071559.QAA29541@crypt.compulink.co.uk>

p4raw-id: //depot/perl@6539

diff --git a/MANIFEST b/MANIFEST
index 96eec9c..add7787 100644 (file)
--- a/MANIFEST
+++ b/MANIFEST
@@ -1398,6 +1398,7 @@ t/op/assignwarn.t See if OP= operators warn correctly for undef targets
 t/op/attrs.t           See if attributes on declarations work
 t/op/auto.t            See if autoincrement et all work
 t/op/avhv.t            See if pseudo-hashes work
+t/op/bless.t           See if bless works
 t/op/bop.t             See if bitops work
 t/op/chars.t           See if character escapes work
 t/op/chop.t            See if chop works

diff --git a/pod/perldiag.pod b/pod/perldiag.pod
index 3699b6e..fd082a1 100644 (file)
--- a/pod/perldiag.pod
+++ b/pod/perldiag.pod
@@ -182,6 +182,24 @@ spots.  This is now heavily deprecated.
 must either both be scalars or both be lists.  Otherwise Perl won't
 know which context to supply to the right side.
 
+=item Attempt to bless into a reference
+
+(F) The CLASSNAME argument to the bless() operator is expected to be
+the name of the package to bless the resulting object into. You've
+supplied instead a reference to something: perhaps you wrote
+
+    bless $self, $proto;
+
+when you intended
+
+    bless $self, ref($proto) || $proto;
+
+If you actually want to bless into the stringified version
+of the reference supplied, you need to stringify it yourself, for
+example by:
+
+    bless $self, "$proto";
+
 =item Attempt to free non-arena SV: 0x%lx
 
 (P internal) All SV objects are supposed to be allocated from arenas

diff --git a/pp.c b/pp.c
index 1621df5..c6bb0a5 100644 (file)
--- a/pp.c
+++ b/pp.c
@@ -561,7 +561,13 @@ PP(pp_bless)
     else {
        SV *ssv = POPs;
        STRLEN len;
-       char *ptr = SvPV(ssv,len);
+       char *ptr;
+
+       if (ssv && SvGMAGICAL(ssv))
+           mg_get(ssv);
+       if (SvROK(ssv))
+           Perl_croak(aTHX_ "Attempt to bless into a reference");
+       ptr = SvPV(ssv,len);
        if (ckWARN(WARN_MISC) && len == 0)
            Perl_warner(aTHX_ WARN_MISC, 
                   "Explicit blessing to '' (assuming package main)");

diff --git a/sv.c b/sv.c
index 20b387c..382805f 100644 (file)
--- a/sv.c
+++ b/sv.c
@@ -2182,7 +2182,10 @@ Perl_sv_2pv(pTHX_ register SV *sv, STRLEN *lp)
                case SVt_PV:
                case SVt_PVIV:
                case SVt_PVNV:
-               case SVt_PVBM:  s = "SCALAR";                   break;
+               case SVt_PVBM:  if (SvROK(sv))
+                                   s = "REF";
+                               else
+                                   s = "SCALAR";               break;
                case SVt_PVLV:  s = "LVALUE";                   break;
                case SVt_PVAV:  s = "ARRAY";                    break;
                case SVt_PVHV:  s = "HASH";                     break;

diff --git a/t/op/bless.t b/t/op/bless.t
new file mode 100644 (file)
index 0000000..3d5d85d
--- /dev/null
+++ b/t/op/bless.t
@@ -0,0 +1,116 @@
+#!./perl
+
+print "1..29\n";
+
+BEGIN {
+    chdir 't' if -d 't';
+    unshift @INC, '../lib' if -d '../lib';
+}
+
+sub expected {
+    my($object, $package, $type) = @_;
+    return "" if (
+       ref($object) eq $package
+       && "$object" =~ /^\Q$package\E=(\w+)\(0x([0-9a-f]+)\)$/
+       && $1 eq $type
+       && hex($2) == $object
+    );
+    print "# $object $package $type\n";
+    return "not ";
+}
+
+# test blessing simple types
+
+$a1 = bless {}, "A";
+print expected($a1, "A", "HASH"), "ok 1\n";
+$b1 = bless [], "B";
+print expected($b1, "B", "ARRAY"), "ok 2\n";
+$c1 = bless \(map "$_", "test"), "C";
+print expected($c1, "C", "SCALAR"), "ok 3\n";
+$d1 = bless \*test, "D";
+print expected($d1, "D", "GLOB"), "ok 4\n";
+$e1 = bless sub { 1 }, "E";
+print expected($e1, "E", "CODE"), "ok 5\n";
+$f1 = bless \[], "F";
+print expected($f1, "F", "REF"), "ok 6\n";
+$g1 = bless \substr("test", 1, 2), "G";
+print expected($g1, "G", "LVALUE"), "ok 7\n";
+
+# blessing ref to object doesn't modify object
+
+print expected(bless(\$a1, "F"), "F", "REF"), "ok 8\n";
+print expected($a1, "A", "HASH"), "ok 9\n";
+
+# reblessing does modify object
+
+$a2 = bless $a1, "A2";
+print expected($a1, "A2", "HASH"), "ok 10\n";
+
+# local and my
+{
+    local $a1 = bless $a1, "A3";       # should rebless outer $a1
+    local $b1 = bless [], "B3";
+    my $c1 = bless $c1, "C3";          # should rebless outer $c1
+    my $d1 = bless \*test2, "D3";
+    print expected($a1, "A3", "HASH"), "ok 11\n";
+    print expected($b1, "B3", "ARRAY"), "ok 12\n";
+    print expected($c1, "C3", "SCALAR"), "ok 13\n";
+    print expected($d1, "D3", "GLOB"), "ok 14\n";
+}
+print expected($a1, "A3", "HASH"), "ok 15\n";
+print expected($b1, "B", "ARRAY"), "ok 16\n";
+print expected($c1, "C3", "SCALAR"), "ok 17\n";
+print expected($d1, "D", "GLOB"), "ok 18\n";
+
+# class is magic
+"E" =~ /(.)/;
+print expected(bless({}, $1), "E", "HASH"), "ok 19\n";
+{
+    local $! = 1;
+    my $string = "$!";
+    $! = 2;    # attempt to avoid cached string
+    $! = 1;
+    print expected(bless({}, $!), $string, "HASH"), "ok 20\n";
+
+# ref is ref to magic
+    {
+       {
+           package F;
+           sub test { ${$_[0]} eq $string or print "not " }
+       }
+       $! = 2;
+       $f1 = bless \$!, "F";
+       $! = 1;
+       $f1->test;
+       print "ok 21\n";
+    }
+}
+
+# ref is magic
+### example of magic variable that is a reference??
+
+# no class, or empty string (with a warning), or undef (with two)
+print expected(bless([]), 'main', "ARRAY"), "ok 22\n";
+{
+    local $SIG{__WARN__} = sub { push @w, join '', @_ };
+    local $^W = 1;
+
+    $m = bless [];
+    print expected($m, 'main', "ARRAY"), "ok 23\n";
+    print @w ? "not ok 24\t# @w\n" : "ok 24\n";
+
+    @w = ();
+    $m = bless [], '';
+    print expected($m, 'main', "ARRAY"), "ok 25\n";
+    print @w != 1 ? "not ok 26\t# @w\n" : "ok 26\n";
+
+    @w = ();
+    $m = bless [], undef;
+    print expected($m, 'main', "ARRAY"), "ok 27\n";
+    print @w != 2 ? "not ok 28\t# @w\n" : "ok 28\n";
+}
+
+# class is a ref
+$a1 = bless {}, "A4";
+$b1 = eval { bless {}, $a1 };
+print $@ ? "ok 29\n" : "not ok 29\t# $b1\n";