Foreach loop causes infinite loop when iterating over generators

[miadey]

Description

When using a foreach loop to iterate over a generator, the loop runs infinitely and never terminates.

Current Behavior

• Generators work correctly with manual iteration using next(), current(), and valid() methods
• However, when using foreach to iterate over a generator, it causes an infinite loop

Expected Behavior

Foreach loops should properly iterate through all yielded values and then terminate.

Test Case to Reproduce

<?php
function gen() {
    yield 1;
    yield 2;
    yield 3;
}

$g = gen();
echo "Starting foreach:\n";
foreach ($g as $value) {
    echo "Got: $value\n";
}
echo "Done\n";
?>

This code should output:

Starting foreach:
Got: 1
Got: 2
Got: 3
Done

But instead it runs infinitely.

Investigation Notes

• The issue appears to be in the foreach generator handling in interpreter.rs around line 15604-15622
• The loop advances the generator first, then checks validity
• The validity check or loop termination condition may be incorrect
• Manual iteration works correctly, so the generator state management is functioning

Related Issues

• This was discovered while fixing #722 (broken generator functionality)
• The core generator issue has been fixed, but foreach iteration remains broken

Priority

High - foreach is the primary way to iterate over generators in PHP

[neeko-cat]

I thought this repo was about a JS engine