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Fix GH-11591: AppendIterator fails to iterate with an empty generator #17316

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Fix GH-11591: AppendIterator fails to iterate with an empty generator #17316

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9 changes: 0 additions & 9 deletions Zend/zend_generators.c
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Original file line number Diff line number Diff line change
Expand Up @@ -872,15 +872,6 @@ ZEND_API void zend_generator_resume(zend_generator *orig_generator) /* {{{ */
}
/* }}} */

static inline void zend_generator_ensure_initialized(zend_generator *generator) /* {{{ */
{
if (UNEXPECTED(Z_TYPE(generator->value) == IS_UNDEF) && EXPECTED(generator->execute_data) && EXPECTED(generator->node.parent == NULL)) {
zend_generator_resume(generator);
generator->flags |= ZEND_GENERATOR_AT_FIRST_YIELD;
}
}
/* }}} */

static inline void zend_generator_rewind(zend_generator *generator) /* {{{ */
{
zend_generator_ensure_initialized(generator);
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8 changes: 8 additions & 0 deletions Zend/zend_generators.h
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Expand Up @@ -105,6 +105,14 @@ static const uint8_t ZEND_GENERATOR_IN_FIBER = 0x10;
void zend_register_generator_ce(void);
ZEND_API void zend_generator_close(zend_generator *generator, bool finished_execution);
ZEND_API void zend_generator_resume(zend_generator *generator);
static inline void zend_generator_ensure_initialized(zend_generator *generator) /* {{{ */
{
if (UNEXPECTED(Z_TYPE(generator->value) == IS_UNDEF) && EXPECTED(generator->execute_data) && EXPECTED(generator->node.parent == NULL)) {
zend_generator_resume(generator);
generator->flags |= ZEND_GENERATOR_AT_FIRST_YIELD;
}
}
/* }}} */
Comment on lines +108 to +115
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I don't really like exposing this in a header.

I would rather prefer creating a new API (e.g. zend_generator_is_empty), but considering you are trying to fix a bug in SPL it seems far more likely that SPL is doing something incorrect in the iterator code.


ZEND_API void zend_generator_restore_call_stack(zend_generator *generator);
ZEND_API zend_execute_data* zend_generator_freeze_call_stack(zend_execute_data *execute_data);
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10 changes: 10 additions & 0 deletions ext/spl/spl_iterators.c
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Expand Up @@ -21,6 +21,7 @@
#include "php.h"
#include "zend_exceptions.h"
#include "zend_interfaces.h"
#include "zend_generators.h"
#include "ext/pcre/php_pcre.h"

#include "spl_iterators.h"
Expand Down Expand Up @@ -2814,6 +2815,15 @@ PHP_METHOD(AppendIterator, append)
RETURN_THROWS();
}

if (instanceof_function(Z_OBJCE_P(it), zend_ce_generator)) {
zend_generator *gen = (zend_generator*)Z_OBJ_P(it);
zend_generator_ensure_initialized(gen);
if (gen->execute_data == NULL) {
/* Skip an empty generator */
return;
}
}

SPL_FETCH_AND_CHECK_DUAL_IT(intern, ZEND_THIS);

if (intern->u.append.iterator->funcs->valid(intern->u.append.iterator) == SUCCESS && spl_dual_it_valid(intern) != SUCCESS) {
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17 changes: 17 additions & 0 deletions ext/spl/tests/gh11591.phpt
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@@ -0,0 +1,17 @@
--TEST--
Bug GH-11591 (Inconsistent behaviour with AppendIterator and empty generators)
--FILE--
<?php
function yieldEmpty()
{
yield from [];
}

$iterator = new AppendIterator();
$iterator->append(yieldEmpty());

foreach ($iterator as $item) {
var_dump($item);
}
?>
--EXPECT--
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