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test.pl: Use END blocks to cancel watchdog timers #23678

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test.pl: Use END blocks to cancel watchdog timers #23678

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ddb2ff9
test.pl: Clarify some comments
khwilliamson Sep 16, 2025
c220b63
test.pl: Don't use watchdog thread unless safe signals
khwilliamson Sep 16, 2025
f028d37
test.pl: Use END blocks to cancel watchdog timers
khwilliamson Sep 16, 2025
97d0c3e
Remove explicit watchdog cancellations at end of program
khwilliamson Sep 3, 2025
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75 changes: 38 additions & 37 deletions t/test.pl
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Original file line number Diff line number Diff line change
Expand Up @@ -38,6 +38,7 @@
our $TODO = 0;
our $NO_ENDING = 0;
our $Tests_Are_Passing = 1;
our @watchdog_threads_;

# Use this instead of print to avoid interference while testing globals.
sub _print {
Expand Down Expand Up @@ -1834,8 +1835,7 @@ sub warning_like {
# NOTE: If the test file uses 'threads', then call the watchdog() function
# _AFTER_ the 'threads' module is loaded.
{ # Closure
my $watchdog;
my $watchdog_thread;
my $cancel_string;

sub watchdog ($;$)
{
Expand All @@ -1844,29 +1844,18 @@ ($;$)
# If cancelling, use the state variables to know which method was used to
# create the watchdog.
if ($timeout == 0) {
if ($watchdog_thread) {
$watchdog_thread->kill('KILL');
undef $watchdog_thread;
}
elsif ($watchdog) {
kill('KILL', $watchdog);
undef $watchdog;
}
else {
alarm(0);
}

eval $cancel_string if defined $cancel_string;
return;
}

# Make sure these aren't defined.
undef $watchdog;
undef $watchdog_thread;

my $method = shift || "";

my $timeout_msg = 'Test process timed out - terminating';

# Common to all cancellation types; HERE gets replaced below by the
# individual code
$cancel_string = 'local $! = 0; local $? = 0; HERE; undef $cancel_string';

# Accept either spelling
my $timeout_factor = $ENV{PERL_TEST_TIME_OUT_FACTOR}
|| $ENV{PERL_TEST_TIMEOUT_FACTOR}
Expand All @@ -1888,9 +1877,13 @@ ($;$)
# shut up use only once warning
my $threads_on = $threads::threads && $threads::threads;

# Don't use a watchdog process if 'threads' is loaded -
# use a watchdog thread instead
if (!$threads_on || $method eq "process") {
# Use a watchdog process unless 'threads' is loaded and is killable by a
# signal
if ( ! $threads_on
|| (defined $ENV{PERL_SIGNALS} && $ENV{PERL_SIGNALS} eq "unsafe")
|| $method eq "process")
{
my $watchdog;

# On Windows and VMS, try launching a watchdog process
# using system(1, ...) (see perlport.pod). system() returns
Expand All @@ -1909,7 +1902,6 @@ ($;$)
return if ($pid_to_kill <= 0);

# Launch watchdog process
undef $watchdog;
eval {
local $SIG{'__WARN__'} = sub {
_diag("Watchdog warning: $_[0]");
Expand Down Expand Up @@ -1950,22 +1942,21 @@ ($;$)
return;
}

# Add END block to parent to terminate and
# clean up watchdog process
eval("END { local \$! = 0; local \$? = 0;
wait() if kill('KILL', $watchdog); };");
# Add END block to parent to terminate and clean up watchdog
# process
$cancel_string =~ s/HERE/wait() if kill('KILL', $watchdog)/;
eval("END { $cancel_string };");
return;
}

# Try using fork() to generate a watchdog process
undef $watchdog;
eval { $watchdog = fork() };
if (defined($watchdog)) {
if ($watchdog) { # Parent process
# Add END block to parent to terminate and
# clean up watchdog process
eval "END { local \$! = 0; local \$? = 0;
wait() if kill('KILL', $watchdog); };";
# Add END block to parent to terminate and clean up watchdog
# process
$cancel_string =~ s/HERE/wait() if kill('KILL', $watchdog)/;
eval("END { $cancel_string };");
return;
}

Expand Down Expand Up @@ -2000,10 +1991,12 @@ ($;$)
# fork() failed - fall through and try using a thread
}

# Use a watchdog thread because either 'threads' is loaded,
# or fork() failed
# Use a watchdog thread because either 'threads' is loaded, or fork()
# failed
if (eval {require threads; 1}) {
$watchdog_thread = 'threads'->create(sub {

# Use an array so can handle multiple timers
push @watchdog_threads_, 'threads'->create(sub {
# Load POSIX if available
eval { require POSIX; };

Expand All @@ -2027,20 +2020,25 @@ ($;$)
kill($sig, $pid_to_kill);
});

#my $index = scalar @watchd
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@tonycoz tonycoz Sep 17, 2025

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comment here seems leftover

$cancel_string =~ s/HERE/\$watchdog_threads_[$#watchdog_threads_]->kill('KILL')/;
eval "END { $cancel_string }";

# Don't proceed until the watchdog has set up its signal handler.
# (Otherwise there is a possibility that we will exit with threads
# running.) The watchdog tells us that the handler is set by
# detaching itself. (The 'is_running()' is a fail-safe.)
while ( $watchdog_thread->is_running()
&& ! $watchdog_thread->is_detached())
while ( $watchdog_threads_[-1]->is_running()
&& ! $watchdog_threads_[-1]->is_detached())
{
'threads'->yield();
}

return;
}

# If everything above fails, then just use an alarm timeout
# If everything above fails, then just use an alarm timeout. There can
# only be one in effect at a time. This cancels any previous one.
WATCHDOG_VIA_ALARM:
if (eval { alarm($timeout); 1; }) {
# Load POSIX if available
Expand All @@ -2054,6 +2052,9 @@ ($;$)
my $sig = $is_vms ? 'TERM' : 'KILL';
kill($sig, $pid_to_kill);
};

$cancel_string =~ s/HERE/alarm(0)/;
eval "END { $cancel_string }";
}
}
} # End closure
Expand Down