[perl5.git] / t / mro / basic.t

#!./perl

use strict;
use warnings;

BEGIN { require q(./test.pl); } plan(tests => 59);

require mro;

{
    package MRO_A;
    our @ISA = qw//;
    package MRO_B;
    our @ISA = qw//;
    package MRO_C;
    our @ISA = qw//;
    package MRO_D;
    our @ISA = qw/MRO_A MRO_B MRO_C/;
    package MRO_E;
    our @ISA = qw/MRO_A MRO_B MRO_C/;
    package MRO_F;
    our @ISA = qw/MRO_D MRO_E/;
}

my @MFO_F_DFS = qw/MRO_F MRO_D MRO_A MRO_B MRO_C MRO_E/;
my @MFO_F_C3 = qw/MRO_F MRO_D MRO_E MRO_A MRO_B MRO_C/;
is(mro::get_mro('MRO_F'), 'dfs');
ok(eq_array(
    mro::get_linear_isa('MRO_F'), \@MFO_F_DFS
));

ok(eq_array(mro::get_linear_isa('MRO_F', 'dfs'), \@MFO_F_DFS));
ok(eq_array(mro::get_linear_isa('MRO_F', 'c3'), \@MFO_F_C3));
eval{mro::get_linear_isa('MRO_F', 'C3')};
like($@, qr/^Invalid mro name: 'C3'/);

mro::set_mro('MRO_F', 'c3');
is(mro::get_mro('MRO_F'), 'c3');
ok(eq_array(
    mro::get_linear_isa('MRO_F'), \@MFO_F_C3
));

ok(eq_array(mro::get_linear_isa('MRO_F', 'dfs'), \@MFO_F_DFS));
ok(eq_array(mro::get_linear_isa('MRO_F', 'c3'), \@MFO_F_C3));
eval{mro::get_linear_isa('MRO_F', 'C3')};
like($@, qr/^Invalid mro name: 'C3'/);

my @isarev = sort { $a cmp $b } @{mro::get_isarev('MRO_B')};
ok(eq_array(
    \@isarev,
    [qw/MRO_D MRO_E MRO_F/]
));

ok(!mro::is_universal('MRO_B'));

@UNIVERSAL::ISA = qw/MRO_F/;
ok(mro::is_universal('MRO_B'));

@UNIVERSAL::ISA = ();
ok(!mro::is_universal('MRO_B'));

# is_universal, get_mro, and get_linear_isa should
# handle non-existent packages sanely
ok(!mro::is_universal('Does_Not_Exist'));
is(mro::get_mro('Also_Does_Not_Exist'), 'dfs');
ok(eq_array(
    mro::get_linear_isa('Does_Not_Exist_Three'),
    [qw/Does_Not_Exist_Three/]
));

# Assigning @ISA via globref
{
    package MRO_TestBase;
    sub testfunc { return 123 }
    package MRO_TestOtherBase;
    sub testfunctwo { return 321 }
    package MRO_M; our @ISA = qw/MRO_TestBase/;
}
*MRO_N::ISA = *MRO_M::ISA;
is(eval { MRO_N->testfunc() }, 123);

# XXX TODO (when there's a way to backtrack through a glob's aliases)
# push(@MRO_M::ISA, 'MRO_TestOtherBase');
# is(eval { MRO_N->testfunctwo() }, 321);

# Simple DESTROY Baseline
{
    my $x = 0;
    my $obj;

    {
        package DESTROY_MRO_Baseline;
        sub new { bless {} => shift }
        sub DESTROY { $x++ }

        package DESTROY_MRO_Baseline_Child;
        our @ISA = qw/DESTROY_MRO_Baseline/;
    }

    $obj = DESTROY_MRO_Baseline->new();
    undef $obj;
    is($x, 1);

    $obj = DESTROY_MRO_Baseline_Child->new();
    undef $obj;
    is($x, 2);
}

# Dynamic DESTROY
{
    my $x = 0;
    my $obj;

    {
        package DESTROY_MRO_Dynamic;
        sub new { bless {} => shift }

        package DESTROY_MRO_Dynamic_Child;
        our @ISA = qw/DESTROY_MRO_Dynamic/;
    }

    $obj = DESTROY_MRO_Dynamic->new();
    undef $obj;
    is($x, 0);

    $obj = DESTROY_MRO_Dynamic_Child->new();
    undef $obj;
    is($x, 0);

    no warnings 'once';
    *DESTROY_MRO_Dynamic::DESTROY = sub { $x++ };

    $obj = DESTROY_MRO_Dynamic->new();
    undef $obj;
    is($x, 1);

    $obj = DESTROY_MRO_Dynamic_Child->new();
    undef $obj;
    is($x, 2);
}

# clearing @ISA in different ways
#  some are destructive to the package, hence the new
#  package name each time
{
    no warnings 'uninitialized';
    {
        package ISACLEAR;
        our @ISA = qw/XX YY ZZ/;
    }
    # baseline
    ok(eq_array(mro::get_linear_isa('ISACLEAR'),[qw/ISACLEAR XX YY ZZ/]));

    # this looks dumb, but it preserves existing behavior for compatibility
    #  (undefined @ISA elements treated as "main")
    $ISACLEAR::ISA[1] = undef;
    ok(eq_array(mro::get_linear_isa('ISACLEAR'),[qw/ISACLEAR XX main ZZ/]));

    # undef the array itself
    undef @ISACLEAR::ISA;
    ok(eq_array(mro::get_linear_isa('ISACLEAR'),[qw/ISACLEAR/]));

    # Now, clear more than one package's @ISA at once
    {
        package ISACLEAR1;
        our @ISA = qw/WW XX/;

        package ISACLEAR2;
        our @ISA = qw/YY ZZ/;
    }
    # baseline
    ok(eq_array(mro::get_linear_isa('ISACLEAR1'),[qw/ISACLEAR1 WW XX/]));
    ok(eq_array(mro::get_linear_isa('ISACLEAR2'),[qw/ISACLEAR2 YY ZZ/]));
    (@ISACLEAR1::ISA, @ISACLEAR2::ISA) = ();

    ok(eq_array(mro::get_linear_isa('ISACLEAR1'),[qw/ISACLEAR1/]));
    ok(eq_array(mro::get_linear_isa('ISACLEAR2'),[qw/ISACLEAR2/]));

    # [perl #49564]  This is a pretty obscure way of clearing @ISA but
    # it tests a regression that affects XS code calling av_clear too.
    {
        package ISACLEAR3;
        our @ISA = qw/WW XX/;
    }
    ok(eq_array(mro::get_linear_isa('ISACLEAR3'),[qw/ISACLEAR3 WW XX/]));
    {
        package ISACLEAR3;
        reset 'I';
    }
    ok(eq_array(mro::get_linear_isa('ISACLEAR3'),[qw/ISACLEAR3/]));
}

# Check that recursion bails out "cleanly" in a variety of cases
# (as opposed to say, bombing the interpreter or something)
{
    my @recurse_codes = (
        '@MRO_R1::ISA = "MRO_R2"; @MRO_R2::ISA = "MRO_R1";',
        '@MRO_R3::ISA = "MRO_R4"; push(@MRO_R4::ISA, "MRO_R3");',
        '@MRO_R5::ISA = "MRO_R6"; @MRO_R6::ISA = qw/XX MRO_R5 YY/;',
        '@MRO_R7::ISA = "MRO_R8"; push(@MRO_R8::ISA, qw/XX MRO_R7 YY/)',
    );
    foreach my $code (@recurse_codes) {
        eval $code;
        ok($@ =~ /Recursive inheritance detected/);
    }
}

# Check that SUPER caches get invalidated correctly
{
    {
        package SUPERTEST;
        sub new { bless {} => shift }
        sub foo { $_[1]+1 }

        package SUPERTEST::MID;
        our @ISA = 'SUPERTEST';

        package SUPERTEST::KID;
        our @ISA = 'SUPERTEST::MID';
        sub foo { my $s = shift; $s->SUPER::foo(@_) }

        package SUPERTEST::REBASE;
        sub foo { $_[1]+3 }
    }

    my $stk_obj = SUPERTEST::KID->new();
    is($stk_obj->foo(1), 2);
    { no warnings 'redefine';
      *SUPERTEST::foo = sub { $_[1]+2 };
    }
    is($stk_obj->foo(2), 4);
    @SUPERTEST::MID::ISA = 'SUPERTEST::REBASE';
    is($stk_obj->foo(3), 6);
}

{ 
  {
    # assigning @ISA via arrayref to globref RT 60220
    package P1;
    sub new { bless {}, shift }
    
    package P2;
  }
  *{P2::ISA} = [ 'P1' ];
  my $foo = P2->new;
  ok(!eval { $foo->bark }, "no bark method");
  no warnings 'once';  # otherwise it'll bark about P1::bark used only once
  *{P1::bark} = sub { "[bark]" };
  is(scalar eval { $foo->bark }, "[bark]", "can bark now");
}

{
  # assigning @ISA via arrayref then modifying it RT 72866
  {
    package Q1;
    sub foo {  }

    package Q2;
    sub bar { }

    package Q3;
  }
  push @Q3::ISA, "Q1";
  can_ok("Q3", "foo");
  *Q3::ISA = [];
  push @Q3::ISA, "Q1";
  can_ok("Q3", "foo");
  *Q3::ISA = [];
  push @Q3::ISA, "Q2";
  can_ok("Q3", "bar");
  ok(!Q3->can("foo"), "can't call foo method any longer");
}

{
    # test mro::method_changed_in
    my $count = mro::get_pkg_gen("MRO_A");
    mro::method_changed_in("MRO_A");
    my $count_new = mro::get_pkg_gen("MRO_A");

    is($count_new, $count + 1);
}

{
    # test if we can call mro::invalidate_all_method_caches;
    eval {
        mro::invalidate_all_method_caches();
    };
    is($@, "");
}

{
    # @main::ISA
    no warnings 'once';
    @main::ISA = 'parent';
    my $output = '';
    *parent::do = sub { $output .= 'parent' };
    *parent2::do = sub { $output .= 'parent2' };
    main->do;
    @main::ISA = 'parent2';
    main->do;
    is $output, 'parentparent2', '@main::ISA is magical';
}

{
    # Undefining *ISA, then modifying @ISA
    # This broke Class::Trait. See [perl #79024].
    {package Class::Trait::Base}
    no strict 'refs';
    undef   *{"Extra::TSpouse::ISA"};
    'Extra::TSpouse'->isa('Class::Trait::Base'); # cache the mro
    unshift @{"Extra::TSpouse::ISA"}, 'Class::Trait::Base';
    ok 'Extra::TSpouse'->isa('Class::Trait::Base'),
     'a isa b after undef *a::ISA and @a::ISA modification';
}

{
    # Deleting $package::{ISA}
    # Broken in 5.10.0; fixed in 5.13.7
    @Blength::ISA = 'Bladd';
    delete $Blength::{ISA};
    ok !Blength->isa("Bladd"), 'delete $package::{ISA}';
}

{
    # Undefining stashes
    @Thrext::ISA = "Thwit";
    @Thwit::ISA = "Sile";
    undef %Thwit::;
    ok !Thrext->isa('Sile'), 'undef %package:: updates subclasses';
}

{
    # Obliterating @ISA via glob assignment
    # Broken in 5.14.0; fixed in 5.17.2
    @Gwythaint::ISA = "Fantastic::Creature";
    undef *This_glob_haD_better_not_exist; # paranoia; must have no array
    *Gwythaint::ISA = *This_glob_haD_better_not_exist;
    ok !Gwythaint->isa("Fantastic::Creature"),
       'obliterating @ISA via glob assignment';
}

{
    # Autovivifying @ISA via @{*ISA}
    no warnings;
    undef *fednu::ISA;
    @{*fednu::ISA} = "pyfg";
    ok +fednu->isa("pyfg"), 'autovivifying @ISA via *{@ISA}';
}

{
    sub Detached::method;
    my $h = delete $::{"Detached::"};
    eval { local *Detached::method };
    is $@, "", 'localising gv-with-cv belonging to detached package';
}

{
    # *ISA localisation
    @il::ISA = "ilsuper";
    sub ilsuper::can { "puree" }
    sub il::tomatoes;
    {
        local *il::ISA;
        is +il->can("tomatoes"), \&il::tomatoes, 'local *ISA';
    }
    is "il"->can("tomatoes"), "puree", 'local *ISA unwinding';
    {
        local *il::ISA = [];
        is +il->can("tomatoes"), \&il::tomatoes, 'local *ISA = []';
    }
    is "il"->can("tomatoes"), "puree", 'local *ISA=[] unwinding';
}
Commit	Line	Data
e1a479c5 BB	1	#!./perl
	2
	3	use strict;
	4	use warnings;
	5
3d460042	6	BEGIN { require q(./test.pl); } plan(tests => 59);
e1a479c5	7
b2685f0c NC	8	require mro;
b2685f0c NC	9
e1a479c5 BB	10	{
	11	package MRO_A;
	12	our @ISA = qw//;
	13	package MRO_B;
	14	our @ISA = qw//;
	15	package MRO_C;
	16	our @ISA = qw//;
	17	package MRO_D;
	18	our @ISA = qw/MRO_A MRO_B MRO_C/;
	19	package MRO_E;
	20	our @ISA = qw/MRO_A MRO_B MRO_C/;
	21	package MRO_F;
	22	our @ISA = qw/MRO_D MRO_E/;
	23	}
	24
84dccb35 NC	25	my @MFO_F_DFS = qw/MRO_F MRO_D MRO_A MRO_B MRO_C MRO_E/;
84dccb35 NC	26	my @MFO_F_C3 = qw/MRO_F MRO_D MRO_E MRO_A MRO_B MRO_C/;
e1a479c5	27	is(mro::get_mro('MRO_F'), 'dfs');
c94dd5be	28	ok(eq_array(
84dccb35	29	mro::get_linear_isa('MRO_F'), \@MFO_F_DFS
c94dd5be	30	));
84dccb35 NC	31
	32	ok(eq_array(mro::get_linear_isa('MRO_F', 'dfs'), \@MFO_F_DFS));
	33	ok(eq_array(mro::get_linear_isa('MRO_F', 'c3'), \@MFO_F_C3));
	34	eval{mro::get_linear_isa('MRO_F', 'C3')};
	35	like($@, qr/^Invalid mro name: 'C3'/);
	36
e1a479c5 BB	37	mro::set_mro('MRO_F', 'c3');
e1a479c5 BB	38	is(mro::get_mro('MRO_F'), 'c3');
c94dd5be	39	ok(eq_array(
84dccb35	40	mro::get_linear_isa('MRO_F'), \@MFO_F_C3
c94dd5be	41	));
e1a479c5	42
84dccb35 NC	43	ok(eq_array(mro::get_linear_isa('MRO_F', 'dfs'), \@MFO_F_DFS));
	44	ok(eq_array(mro::get_linear_isa('MRO_F', 'c3'), \@MFO_F_C3));
	45	eval{mro::get_linear_isa('MRO_F', 'C3')};
	46	like($@, qr/^Invalid mro name: 'C3'/);
	47
70cd14a1	48	my @isarev = sort { $a cmp $b } @{mro::get_isarev('MRO_B')};
c94dd5be RGS	49	ok(eq_array(
c94dd5be RGS	50	\@isarev,
e1a479c5	51	[qw/MRO_D MRO_E MRO_F/]
c94dd5be	52	));
e1a479c5 BB	53
	54	ok(!mro::is_universal('MRO_B'));
	55
	56	@UNIVERSAL::ISA = qw/MRO_F/;
	57	ok(mro::is_universal('MRO_B'));
	58
	59	@UNIVERSAL::ISA = ();
80ebaca2	60	ok(!mro::is_universal('MRO_B'));
70cd14a1 CB	61
70cd14a1 CB	62	# is_universal, get_mro, and get_linear_isa should
93f09d7b	63	# handle non-existent packages sanely
70cd14a1 CB	64	ok(!mro::is_universal('Does_Not_Exist'));
	65	is(mro::get_mro('Also_Does_Not_Exist'), 'dfs');
	66	ok(eq_array(
	67	mro::get_linear_isa('Does_Not_Exist_Three'),
	68	[qw/Does_Not_Exist_Three/]
	69	));
	70
	71	# Assigning @ISA via globref
	72	{
	73	package MRO_TestBase;
	74	sub testfunc { return 123 }
	75	package MRO_TestOtherBase;
	76	sub testfunctwo { return 321 }
	77	package MRO_M; our @ISA = qw/MRO_TestBase/;
	78	}
	79	MRO_N::ISA = MRO_M::ISA;
	80	is(eval { MRO_N->testfunc() }, 123);
	81
	82	# XXX TODO (when there's a way to backtrack through a glob's aliases)
	83	# push(@MRO_M::ISA, 'MRO_TestOtherBase');
	84	# is(eval { MRO_N->testfunctwo() }, 321);
9b439311 BB	85
	86	# Simple DESTROY Baseline
	87	{
	88	my $x = 0;
	89	my $obj;
	90
	91	{
	92	package DESTROY_MRO_Baseline;
	93	sub new { bless {} => shift }
	94	sub DESTROY { $x++ }
	95
	96	package DESTROY_MRO_Baseline_Child;
	97	our @ISA = qw/DESTROY_MRO_Baseline/;
	98	}
	99
	100	$obj = DESTROY_MRO_Baseline->new();
	101	undef $obj;
	102	is($x, 1);
	103
	104	$obj = DESTROY_MRO_Baseline_Child->new();
	105	undef $obj;
	106	is($x, 2);
	107	}
	108
	109	# Dynamic DESTROY
	110	{
	111	my $x = 0;
	112	my $obj;
	113
	114	{
	115	package DESTROY_MRO_Dynamic;
	116	sub new { bless {} => shift }
	117
	118	package DESTROY_MRO_Dynamic_Child;
	119	our @ISA = qw/DESTROY_MRO_Dynamic/;
	120	}
	121
	122	$obj = DESTROY_MRO_Dynamic->new();
	123	undef $obj;
	124	is($x, 0);
	125
	126	$obj = DESTROY_MRO_Dynamic_Child->new();
	127	undef $obj;
	128	is($x, 0);
	129
	130	no warnings 'once';
	131	*DESTROY_MRO_Dynamic::DESTROY = sub { $x++ };
	132
	133	$obj = DESTROY_MRO_Dynamic->new();
	134	undef $obj;
	135	is($x, 1);
	136
	137	$obj = DESTROY_MRO_Dynamic_Child->new();
	138	undef $obj;
	139	is($x, 2);
	140	}
22717f83 BB	141
22717f83 BB	142	# clearing @ISA in different ways
5be5c7a6 BB	143	# some are destructive to the package, hence the new
5be5c7a6 BB	144	# package name each time
22717f83 BB	145	{
	146	no warnings 'uninitialized';
	147	{
	148	package ISACLEAR;
	149	our @ISA = qw/XX YY ZZ/;
	150	}
	151	# baseline
	152	ok(eq_array(mro::get_linear_isa('ISACLEAR'),[qw/ISACLEAR XX YY ZZ/]));
	153
	154	# this looks dumb, but it preserves existing behavior for compatibility
	155	# (undefined @ISA elements treated as "main")
	156	$ISACLEAR::ISA[1] = undef;
	157	ok(eq_array(mro::get_linear_isa('ISACLEAR'),[qw/ISACLEAR XX main ZZ/]));
	158
5be5c7a6	159	# undef the array itself
22717f83 BB	160	undef @ISACLEAR::ISA;
22717f83 BB	161	ok(eq_array(mro::get_linear_isa('ISACLEAR'),[qw/ISACLEAR/]));
915d8d75 RD	162
	163	# Now, clear more than one package's @ISA at once
	164	{
	165	package ISACLEAR1;
	166	our @ISA = qw/WW XX/;
	167
	168	package ISACLEAR2;
	169	our @ISA = qw/YY ZZ/;
	170	}
	171	# baseline
	172	ok(eq_array(mro::get_linear_isa('ISACLEAR1'),[qw/ISACLEAR1 WW XX/]));
	173	ok(eq_array(mro::get_linear_isa('ISACLEAR2'),[qw/ISACLEAR2 YY ZZ/]));
	174	(@ISACLEAR1::ISA, @ISACLEAR2::ISA) = ();
	175
934dcd01	176	ok(eq_array(mro::get_linear_isa('ISACLEAR1'),[qw/ISACLEAR1/]));
915d8d75	177	ok(eq_array(mro::get_linear_isa('ISACLEAR2'),[qw/ISACLEAR2/]));
52b45067 RD	178
	179	# [perl #49564] This is a pretty obscure way of clearing @ISA but
	180	# it tests a regression that affects XS code calling av_clear too.
	181	{
	182	package ISACLEAR3;
	183	our @ISA = qw/WW XX/;
	184	}
	185	ok(eq_array(mro::get_linear_isa('ISACLEAR3'),[qw/ISACLEAR3 WW XX/]));
	186	{
	187	package ISACLEAR3;
	188	reset 'I';
	189	}
	190	ok(eq_array(mro::get_linear_isa('ISACLEAR3'),[qw/ISACLEAR3/]));
915d8d75 RD	191	}
	192
	193	# Check that recursion bails out "cleanly" in a variety of cases
	194	# (as opposed to say, bombing the interpreter or something)
	195	{
	196	my @recurse_codes = (
	197	'@MRO_R1::ISA = "MRO_R2"; @MRO_R2::ISA = "MRO_R1";',
	198	'@MRO_R3::ISA = "MRO_R4"; push(@MRO_R4::ISA, "MRO_R3");',
	199	'@MRO_R5::ISA = "MRO_R6"; @MRO_R6::ISA = qw/XX MRO_R5 YY/;',
	200	'@MRO_R7::ISA = "MRO_R8"; push(@MRO_R8::ISA, qw/XX MRO_R7 YY/)',
	201	);
	202	foreach my $code (@recurse_codes) {
	203	eval $code;
	204	ok($@ =~ /Recursive inheritance detected/);
	205	}
22717f83	206	}
915d8d75	207
2e7640f0 BB	208	# Check that SUPER caches get invalidated correctly
	209	{
	210	{
	211	package SUPERTEST;
	212	sub new { bless {} => shift }
	213	sub foo { $_[1]+1 }
	214
	215	package SUPERTEST::MID;
	216	our @ISA = 'SUPERTEST';
	217
	218	package SUPERTEST::KID;
	219	our @ISA = 'SUPERTEST::MID';
	220	sub foo { my $s = shift; $s->SUPER::foo(@_) }
	221
	222	package SUPERTEST::REBASE;
	223	sub foo { $_[1]+3 }
	224	}
	225
	226	my $stk_obj = SUPERTEST::KID->new();
	227	is($stk_obj->foo(1), 2);
	228	{ no warnings 'redefine';
	229	*SUPERTEST::foo = sub { $_[1]+2 };
	230	}
	231	is($stk_obj->foo(2), 4);
	232	@SUPERTEST::MID::ISA = 'SUPERTEST::REBASE';
	233	is($stk_obj->foo(3), 6);
	234	}
	235
26d68d86 TC	236	{
	237	{
	238	# assigning @ISA via arrayref to globref RT 60220
	239	package P1;
	240	sub new { bless {}, shift }
	241
	242	package P2;
	243	}
	244	*{P2::ISA} = [ 'P1' ];
	245	my $foo = P2->new;
	246	ok(!eval { $foo->bark }, "no bark method");
	247	no warnings 'once'; # otherwise it'll bark about P1::bark used only once
	248	*{P1::bark} = sub { "[bark]" };
	249	is(scalar eval { $foo->bark }, "[bark]", "can bark now");
	250	}
4283ec8b B	251
4283ec8b B	252	{
d851b122 TC	253	# assigning @ISA via arrayref then modifying it RT 72866
	254	{
	255	package Q1;
	256	sub foo { }
	257
	258	package Q2;
	259	sub bar { }
	260
	261	package Q3;
	262	}
	263	push @Q3::ISA, "Q1";
	264	can_ok("Q3", "foo");
	265	*Q3::ISA = [];
	266	push @Q3::ISA, "Q1";
	267	can_ok("Q3", "foo");
	268	*Q3::ISA = [];
	269	push @Q3::ISA, "Q2";
	270	can_ok("Q3", "bar");
	271	ok(!Q3->can("foo"), "can't call foo method any longer");
	272	}
	273
	274	{
4283ec8b B	275	# test mro::method_changed_in
	276	my $count = mro::get_pkg_gen("MRO_A");
	277	mro::method_changed_in("MRO_A");
	278	my $count_new = mro::get_pkg_gen("MRO_A");
	279
	280	is($count_new, $count + 1);
	281	}
	282
	283	{
	284	# test if we can call mro::invalidate_all_method_caches;
	285	eval {
	286	mro::invalidate_all_method_caches();
	287	};
	288	is($@, "");
	289	}
44428a46 FC	290
	291	{
	292	# @main::ISA
	293	no warnings 'once';
	294	@main::ISA = 'parent';
	295	my $output = '';
	296	*parent::do = sub { $output .= 'parent' };
	297	*parent2::do = sub { $output .= 'parent2' };
	298	main->do;
	299	@main::ISA = 'parent2';
	300	main->do;
	301	is $output, 'parentparent2', '@main::ISA is magical';
	302	}
af16de9f FC	303
	304	{
	305	# Undefining *ISA, then modifying @ISA
	306	# This broke Class::Trait. See [perl #79024].
	307	{package Class::Trait::Base}
	308	no strict 'refs';
	309	undef *{"Extra::TSpouse::ISA"};
	310	'Extra::TSpouse'->isa('Class::Trait::Base'); # cache the mro
	311	unshift @{"Extra::TSpouse::ISA"}, 'Class::Trait::Base';
	312	ok 'Extra::TSpouse'->isa('Class::Trait::Base'),
	313	'a isa b after undef *a::ISA and @a::ISA modification';
	314	}
f3d2f32d FC	315
	316	{
	317	# Deleting $package::{ISA}
	318	# Broken in 5.10.0; fixed in 5.13.7
	319	@Blength::ISA = 'Bladd';
	320	delete $Blength::{ISA};
	321	ok !Blength->isa("Bladd"), 'delete $package::{ISA}';
	322	}
b9e30492 FC	323
	324	{
	325	# Undefining stashes
	326	@Thrext::ISA = "Thwit";
	327	@Thwit::ISA = "Sile";
	328	undef %Thwit::;
	329	ok !Thrext->isa('Sile'), 'undef %package:: updates subclasses';
	330	}
dfedf892 FC	331
	332	{
	333	# Obliterating @ISA via glob assignment
	334	# Broken in 5.14.0; fixed in 5.17.2
	335	@Gwythaint::ISA = "Fantastic::Creature";
	336	undef *This_glob_haD_better_not_exist; # paranoia; must have no array
	337	Gwythaint::ISA = This_glob_haD_better_not_exist;
	338	ok !Gwythaint->isa("Fantastic::Creature"),
	339	'obliterating @ISA via glob assignment';
	340	}
986d39ee FC	341
	342	{
	343	# Autovivifying @ISA via @{*ISA}
40099ff6	344	no warnings;
986d39ee FC	345	undef *fednu::ISA;
	346	@{*fednu::ISA} = "pyfg";
	347	ok +fednu->isa("pyfg"), 'autovivifying @ISA via *{@ISA}';
	348	}
959f7ad7 FC	349
	350	{
	351	sub Detached::method;
	352	my $h = delete $::{"Detached::"};
	353	eval { local *Detached::method };
	354	is $@, "", 'localising gv-with-cv belonging to detached package';
	355	}
3d460042 FC	356
	357	{
	358	# *ISA localisation
	359	@il::ISA = "ilsuper";
	360	sub ilsuper::can { "puree" }
	361	sub il::tomatoes;
	362	{
	363	local *il::ISA;
	364	is +il->can("tomatoes"), \&il::tomatoes, 'local *ISA';
	365	}
	366	is "il"->can("tomatoes"), "puree", 'local *ISA unwinding';
	367	{
	368	local *il::ISA = [];
	369	is +il->can("tomatoes"), \&il::tomatoes, 'local *ISA = []';
	370	}
	371	is "il"->can("tomatoes"), "puree", 'local *ISA=[] unwinding';
	372	}