Garbage collection stops after exception in SoapClient

[abienvenu]

Description

The following code:

<?php

class A
{
	public $b;
}

class B
{
	public $a;
}

function buildCycle()
{
	$a = new A();
	$b = new B();
	$a->b = $b;
	$b->a = $a;
}

function failySoapCall()
{

	try {
		new SoapClient('https://nowhere.inexistent.space/?WSDL');
	}
	catch (Exception) {
		echo "Soap call failed\n";
	}
}

function gc()
{
	gc_collect_cycles();
	echo "GC Runs: " . gc_status()['runs'] . "\n";
}


buildCycle();
gc();
buildCycle();
gc();
buildCycle();
gc();

failySoapCall();

buildCycle();
gc();
buildCycle();
gc();
buildCycle();
gc();

Resulted in this output:

GC Runs: 1
GC Runs: 2
GC Runs: 3
Soap call failed
GC Runs: 3
GC Runs: 3
GC Runs: 3

But I expected this output instead:

GC Runs: 1
GC Runs: 2
GC Runs: 3
Soap call failed
GC Runs: 4
GC Runs: 5
GC Runs: 6

The SOAP exception apparently stops the garbage collector. I experienced this problem with a large, long running process. Its memory usage is intensive but stable. Until it encounters a SOAP exception: its memory usage skyrockets, and gc_status() reports that no more gc run is done.

PHP Version

PHP 8.1.13

Operating System

Alpine 3.16

[cmb69]

The problem is Soap's error handling, which calls _zend_bailout() and there:

php-src/Zend/zend.c

Line 1185 in 64f5f53

gc_protect(1);

The fix for the reported issue appears to be trivial:

 ext/soap/soap.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/ext/soap/soap.c b/ext/soap/soap.c
index de29917cd8..5b02f74ba9 100644
--- a/ext/soap/soap.c
+++ b/ext/soap/soap.c
@@ -124,7 +124,8 @@ static void soap_error_handler(int error_num, zend_string *error_filename, const
 	SOAP_GLOBAL(soap_version) = _old_soap_version;\
 	if (_bailout) {\
 		zend_bailout();\
-	}
+	}\
+	gc_protect(0);
 
 #define FETCH_THIS_SDL(ss) \
 	{ \

However, there are more issues in other places (probably not only in ext/soap).

[nielsdos]

If no one is working on this yet, I can try to check other places too soon-ish, and write a PR.

[cmb69]

If no one is working on this yet, I can try to check other places too soon-ish, and write a PR.

Great! I'm not planning to work on this. :)