Move stack->next assignment within if (stack) check #10090
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iluuu1994
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Dec 12, 2022
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Thank you! There seem to be no calls to phpdbg_stack_free() with NULL (which would crash on any reasonable platform). Thus it might make sense to just assert that the value isn't NULL and remove the check from the if condition. master is fine, as this check is essentially just redundant.
The code checks if stack is a NULL pointer. Below that if the stack->next pointer is updated unconditionally. Therefore a call with a NULL pointer will crash, even though the if (stack) check seems to show the intent that it is valid to call the function with NULL. The function is not meant to be called with NULL, so just ZEND_ASSERT instead.
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The code checks if stack is a NULL pointer. Below that if the stack->next pointer is updated unconditionally. Therefore a call with a NULL pointer will crash, even though the if (stack) check shows the intent that it is valid to call the function with NULL. The assignment to stack->next was not in the initial version of the code. Fix it by moving the assignment inside the if's body.
Note: I'm not sure if this should go into master or into 8.1, I chose master for now. Technically it is a bugfix, but it also likely doesn't affect existing uses because otherwise there likely would've been a bug report somewhere.