This fixes bugs #65035 and #65161. In one of the bugs the issue is
that function_state.arguments is NULL, but the arg count is pushed
to the stack and the code tries to free it. In the other bug the
stack of the generator is freed twice, once in generator_close and
later during shutdown.
It's rather hard (if at all possible) to do a proper stack cleanup
on an unclean shutdown, so I'm just disabling it in this case.
This also reverses the destruction order of the pushed arguments to
align with how it is done everywhere else.
I'm not exactly sure whether this is the right way to fix it, but it
seems to work fine.
Rule of thumb: Always implement the object clone handler rather
than the object storage clone handler. Actually I think we should
drop the latter. It's nearly never usable.
If a generator is destroyed in a finally block it will resume the generator to run that finally
block before freeing the generator. This was done in the object storage free handler.
Running user code in the free handler isn't safe though because the free handlers may be run
during request shutdown, already after several key components have been shut down.
This is avoided by doing the finally handling in the dtor handler. These handlers are run at the
start of the shutdown sequence.
Generator::throw($exception) throws an exception into the generator. The
exception is thrown at the current point of suspension within the generator.
It basically behaves as if the current yield statement were replaced with
a throw statement and the generator subsequently resumed.
If zend_generator_close is called from within zend_generator_resume (e.g.
due to a return statement) then all the EGs will still be using the values
from the generator. That's why the stack frame has to be the last thing
that is dtored, otherwise some other dtor that is using
EG(current_execute_data) might access the already freed memory segment.
This was the case with the closure dtor.
The fix is to move the dtors for key and value to the start of the handler.
This way the stack frame is the last thing that is freed.
When the return value of yield wasn't used it was leaked.
This is fixed by using a TMP_VAR return value instead of VAR. TMP_VARs are
automatically freed when they aren't used.
EG(arg_types_stack) is now also backed up when generators are used. This
allows the use of yield in nested method calls.
This commit adds two new functions to the zend_ptr_stack API:
zend_ptr_stack_push_from_memory
zend_ptr_stack_pop_into_memory
both taking the following arguments:
zend_ptr_stack *stack, int count, void **pointers
If you try to traverse an already closed generator an exception will now be
thrown.
Furthermore this changes the error for traversing a by-val generator by-ref
from an E_ERROR to an Exception.
* Trying to resume a generator while it is already running now throws a
fatal error.
* Trying to use yield in finally while the generator is being force-closed
(by GC) throws a fatal error.
* Rewinding after the first yield now throws an Exception
It looks like you have to implement the Iterator interface *before*
assigning get_iterator. Otherwise the structure for user iterators isn't
correctly zeroed out.
Additionaly I'm setting class_entry->iterator_funcs.funcs now. Not sure if
this is strictly necessary, but better safe than sorry ;)
If a generator threw an exception and was iterated using foreach (i.e. not
manually) an infinite loop was triggered. The reason was that the exception
was not properly rethrown using zend_throw_exception_internal.
Generators are now automatically detected by the presence of a `yield`
expression in their body.
This removes the ZEND_SUSPEND_AND_RETURN_GENERATOR opcode. Instead
additional checks for ZEND_ACC_GENERATOR are added to the fcall_common
helper and zend_call_function.
This also adds a new function zend_generator_create_zval, which handles
the actual creation of the generator zval from an op array.
I feel like I should deglobalize the zend_create_execute_data_from_op_array
code a bit. It currently changes EG(current_execute_data) and
EG(opline_ptr) which is somewhat confusing (given the name).
Previously the zval* of the generator was passed into the VM by misusing
EG(return_value_ptr_ptr). Now the zend_generator* itself is directly passed
in. This saves us from always having to pass the zval* around everywhere.
To make the generator function show up in backtraces one has to insert an
additional execute_data into the chain, as prev_execute_data->function_state
is used to determine the called function.
Adding the additional stack frame is also required for func_get_args(), as
the arguments are fetched from there too. The arguments have to be copied
in order to keep them around. Due to the way they are saved doing so is
quite ugly, so I added another function zend_copy_arguments to zend_execute.c
which handles this.
The current situation is still not perfect, as the generator function itself
does not appear in the stack trace. This makes sense in some way, but it
would probably be more helpful if it would show up (with the bound arguments)
after the $generator->xyz() call. This could be misleading too though as the
function is not *really* called there.
