source: trunk/essentials/dev-lang/perl/t/op/goto.t

#!./perl

# "This IS structured code.  It's just randomly structured."

BEGIN {
    chdir 't' if -d 't';
    @INC = qw(. ../lib);
    require "test.pl";
}

use warnings;
use strict;
plan tests => 57;

our $foo;
while ($?) {
    $foo = 1;
  label1:
    $foo = 2;
    goto label2;
} continue {
    $foo = 0;
    goto label4;
  label3:
    $foo = 4;
    goto label4;
}
goto label1;

$foo = 3;

label2:
is($foo, 2, 'escape while loop');
goto label3;

label4:
is($foo, 4, 'second escape while loop');

my $r = run_perl(prog => 'goto foo;', stderr => 1);
like($r, qr/label/, 'cant find label');

my $ok = 0;
sub foo {
    goto bar;
    return;
bar:
    $ok = 1;
}

&foo;
ok($ok, 'goto in sub');

sub bar {
    my $x = 'bypass';
    eval "goto $x";
}

&bar;
exit;

FINALE:
is(curr_test(), 16, 'FINALE');

# does goto LABEL handle block contexts correctly?
# note that this scope-hopping differs from last & next,
# which always go up-scope strictly.
my $count = 0;
my $cond = 1;
for (1) {
    if ($cond == 1) {
        $cond = 0;
        goto OTHER;
    }
    elsif ($cond == 0) {
      OTHER:
        $cond = 2;
        is($count, 0, 'OTHER');
        $count++;
        goto THIRD;
    }
    else {
      THIRD:
        is($count, 1, 'THIRD');
        $count++;
    }
}
is($count, 2, 'end of loop');

# Does goto work correctly within a for(;;) loop?
#  (BUG ID 20010309.004)

for(my $i=0;!$i++;) {
  my $x=1;
  goto label;
  label: is($x, 1, 'goto inside a for(;;) loop body from inside the body');
}

# Does goto work correctly going *to* a for(;;) loop?
#  (make sure it doesn't skip the initializer)

my ($z, $y) = (0);
FORL1: for ($y=1; $z;) {
    ok($y, 'goto a for(;;) loop, from outside (does initializer)');
    goto TEST19}
($y,$z) = (0, 1);
goto FORL1;

# Even from within the loop?
TEST19: $z = 0;
FORL2: for($y=1; 1;) {
  if ($z) {
    ok($y, 'goto a for(;;) loop, from inside (does initializer)');
    last;
  }
  ($y, $z) = (0, 1);
  goto FORL2;
}

# Does goto work correctly within a try block?
#  (BUG ID 20000313.004) - [perl #2359]
$ok = 0;
eval {
  my $variable = 1;
  goto LABEL20;
  LABEL20: $ok = 1 if $variable;
};
ok($ok, 'works correctly within a try block');
is($@, "", '...and $@ not set');

# And within an eval-string?
$ok = 0;
eval q{
  my $variable = 1;
  goto LABEL21;
  LABEL21: $ok = 1 if $variable;
};
ok($ok, 'works correctly within an eval string');
is($@, "", '...and $@ still not set');


# Test that goto works in nested eval-string
$ok = 0;
{eval q{
  eval q{
    goto LABEL22;
  };
  $ok = 0;
  last;

  LABEL22: $ok = 1;
};
$ok = 0 if $@;
}
ok($ok, 'works correctly in a nested eval string');

{
    my $false = 0;
    my $count;

    $ok = 0;
    { goto A; A: $ok = 1 } continue { }
    ok($ok, '#20357 goto inside /{ } continue { }/ loop');

    $ok = 0;
    { do { goto A; A: $ok = 1 } while $false }
    ok($ok, '#20154 goto inside /do { } while ()/ loop');
    $ok = 0;
    foreach(1) { goto A; A: $ok = 1 } continue { };
    ok($ok, 'goto inside /foreach () { } continue { }/ loop');

    $ok = 0;
    sub a {
        A: { if ($false) { redo A; B: $ok = 1; redo A; } }
        goto B unless $count++;
    }
    a();
    ok($ok, '#19061 loop label wiped away by goto');

    $ok = 0;
    my $p;
    for ($p=1;$p && goto A;$p=0) { A: $ok = 1 }
    ok($ok, 'weird case of goto and for(;;) loop');
}

# bug #9990 - don't prematurely free the CV we're &going to.

sub f1 {
    my $x;
    goto sub { $x=0; ok(1,"don't prematurely free CV\n") }
}
f1();

# bug #22181 - this used to coredump or make $x undefined, due to
# erroneous popping of the inner BLOCK context

undef $ok;
for ($count=0; $count<2; $count++) {
    my $x = 1;
    goto LABEL29;
    LABEL29:
    $ok = $x;
}
is($ok, 1, 'goto in for(;;) with continuation');

# bug #22299 - goto in require doesn't find label

open my $f, ">goto01.pm" or die;
print $f <<'EOT';
package goto01;
goto YYY;
die;
YYY: print "OK\n";
1;
EOT
close $f;

$r = runperl(prog => 'use goto01; print qq[DONE\n]');
is($r, "OK\nDONE\n", "goto within use-d file"); 
unlink "goto01.pm";

# test for [perl #24108]
$ok = 1;
$count = 0;
sub i_return_a_label {
    $count++;
    return "returned_label";
}
eval { goto +i_return_a_label; };
$ok = 0;

returned_label:
is($count, 1, 'called i_return_a_label');
ok($ok, 'skipped to returned_label');

# [perl #29708] - goto &foo could leave foo() at depth two with
# @_ == PL_sv_undef, causing a coredump


$r = runperl(
    prog =>
        'sub f { return if $d; $d=1; my $a=sub {goto &f}; &$a; f() } f(); print qq(ok\n)',
    stderr => 1
    );
is($r, "ok\n", 'avoid pad without an @_');

goto moretests;
fail('goto moretests');
exit;

bypass:

is(curr_test(), 5, 'eval "goto $x"');

# Test autoloading mechanism.

sub two {
    my ($pack, $file, $line) = caller;  # Should indicate original call stats.
    is("@_ $pack $file $line", "1 2 3 main $::FILE $::LINE",
        'autoloading mechanism.');
}

sub one {
    eval <<'END';
    no warnings 'redefine';
    sub one { pass('sub one'); goto &two; fail('sub one tail'); }
END
    goto &one;
}

$::FILE = __FILE__;
$::LINE = __LINE__ + 1;
&one(1,2,3);

{
    my $wherever = 'NOWHERE';
    eval { goto $wherever };
    like($@, qr/Can't find label NOWHERE/, 'goto NOWHERE sets $@');
}

# see if a modified @_ propagates
{
  my $i;
  package Foo;
  sub DESTROY   { my $s = shift; ::is($s->[0], $i, "destroy $i"); }
  sub show      { ::is(+@_, 5, "show $i",); }
  sub start     { push @_, 1, "foo", {}; goto &show; }
  for (1..3)    { $i = $_; start(bless([$_]), 'bar'); }
}

sub auto {
    goto &loadit;
}

sub AUTOLOAD { $ok = 1 if "@_" eq "foo" }

$ok = 0;
auto("foo");
ok($ok, 'autoload');

{
    my $wherever = 'FINALE';
    goto $wherever;
}
fail('goto $wherever');

moretests:
# test goto duplicated labels.
{
    my $z = 0;
    eval {
        $z = 0;
        for (0..1) {
          L4: # not outer scope
            $z += 10;
            last;
        }
        goto L4 if $z == 10;
        last;
    };
    like($@, qr/Can't "goto" into the middle of a foreach loop/,
            'catch goto middle of foreach');

    $z = 0;
    # ambiguous label resolution (outer scope means endless loop!)
  L1:
    for my $x (0..1) {
        $z += 10;
        is($z, 10, 'prefer same scope (loop body) to outer scope (loop entry)');
        goto L1 unless $x;
        $z += 10;
      L1:
        is($z, 10, 'prefer same scope: second');
        last;
    }

    $z = 0;
  L2: 
    { 
        $z += 10;
        is($z, 10, 'prefer this scope (block body) to outer scope (block entry)');
        goto L2 if $z == 10;
        $z += 10;
      L2:
        is($z, 10, 'prefer this scope: second');
    }


    { 
        $z = 0;
        while (1) {
          L3: # not inner scope
            $z += 10;
            last;
        }
        is($z, 10, 'prefer this scope to inner scope');
        goto L3 if $z == 10;
        $z += 10;
      L3: # this scope !
        is($z, 10, 'prefer this scope to inner scope: second');
    }

  L4: # not outer scope
    { 
        $z = 0;
        while (1) {
          L4: # not inner scope
            $z += 1;
            last;
        }
        is($z, 1, 'prefer this scope to inner,outer scopes');
        goto L4 if $z == 1;
        $z += 10;
      L4: # this scope !
        is($z, 1, 'prefer this scope to inner,outer scopes: second');
    }

    {
        my $loop = 0;
        for my $x (0..1) { 
          L2: # without this, fails 1 (middle) out of 3 iterations
            $z = 0;
          L2: 
            $z += 10;
            is($z, 10,
                "same label, multiple times in same scope (choose 1st) $loop");
            goto L2 if $z == 10 and not $loop++;
        }
    }
}

# deep recursion with gotos eventually caused a stack reallocation
# which messed up buggy internals that didn't expect the stack to move

sub recurse1 {
    unshift @_, "x";
    no warnings 'recursion';
    goto &recurse2;
}
sub recurse2 {
    my $x = shift;
    $_[0] ? +1 + recurse1($_[0] - 1) : 0
}
is(recurse1(500), 500, 'recursive goto &foo');

# [perl #32039] Chained goto &sub drops data too early. 

sub a32039 { @_=("foo"); goto &b32039; }
sub b32039 { goto &c32039; }
sub c32039 { is($_[0], 'foo', 'chained &goto') }
a32039();

# [perl #35214] next and redo re-entered the loop with the wrong cop,
# causing a subsequent goto to crash

{
    my $r = runperl(
                stderr => 1,
                prog =>
'for ($_=0;$_<3;$_++){A: if($_==1){next} if($_==2){$_++;goto A}}print qq(ok\n)'
    );
    is($r, "ok\n", 'next and goto');

    $r = runperl(
                stderr => 1,
                prog =>
'for ($_=0;$_<3;$_++){A: if($_==1){$_++;redo} if($_==2){$_++;goto A}}print qq(ok\n)'
    );
    is($r, "ok\n", 'redo and goto');
}

# goto &foo not allowed in evals


sub null { 1 };
eval 'goto &null';
like($@, qr/Can't goto subroutine from an eval-string/, 'eval string');
eval { goto &null };
like($@, qr/Can't goto subroutine from an eval-block/, 'eval block');

# [perl #36521] goto &foo in warn handler could defeat recursion avoider

{
    my $r = runperl(
                stderr => 1,
                prog => 'my $d; my $w = sub { return if $d++; warn q(bar)}; local $SIG{__WARN__} = sub { goto &$w; }; warn q(foo);'
    );
    like($r, qr/bar/, "goto &foo in warn");
}