py/objgenerator: Protect against reentering a generator.

Generators that are already executing cannot be reexecuted.  This patch
puts in a check for such a case.

Thanks to @jepler for finding the bug.
This commit is contained in:
Damien George 2018-05-22 16:54:03 +10:00
parent 771cb359af
commit 400273a799
3 changed files with 26 additions and 1 deletions

View File

@ -117,9 +117,19 @@ mp_vm_return_kind_t mp_obj_gen_resume(mp_obj_t self_in, mp_obj_t send_value, mp_
*self->code_state.sp = send_value;
}
}
// We set self->globals=NULL while executing, for a sentinel to ensure the generator
// cannot be reentered during execution
if (self->globals == NULL) {
mp_raise_ValueError("generator already executing");
}
// Set up the correct globals context for the generator and execute it
self->code_state.old_globals = mp_globals_get();
mp_globals_set(self->globals);
self->globals = NULL;
mp_vm_return_kind_t ret_kind = mp_execute_bytecode(&self->code_state, throw_value);
self->globals = mp_globals_get();
mp_globals_set(self->code_state.old_globals);
switch (ret_kind) {

View File

@ -0,0 +1,15 @@
# yielding from an already executing generator is not allowed
def f():
yield 1
# g here is already executing so this will raise an exception
yield from g
g = f()
print(next(g))
try:
next(g)
except ValueError:
print('ValueError')

View File

@ -336,7 +336,7 @@ def run_tests(pyb, tests, args, base_path="."):
# Some tests are known to fail with native emitter
# Remove them from the below when they work
if args.emit == 'native':
skip_tests.update({'basics/%s.py' % t for t in 'gen_yield_from gen_yield_from_close gen_yield_from_ducktype gen_yield_from_exc gen_yield_from_iter gen_yield_from_send gen_yield_from_stopped gen_yield_from_throw gen_yield_from_throw2 gen_yield_from_throw3 generator1 generator2 generator_args generator_close generator_closure generator_exc generator_pend_throw generator_return generator_send'.split()}) # require yield
skip_tests.update({'basics/%s.py' % t for t in 'gen_yield_from gen_yield_from_close gen_yield_from_ducktype gen_yield_from_exc gen_yield_from_executing gen_yield_from_iter gen_yield_from_send gen_yield_from_stopped gen_yield_from_throw gen_yield_from_throw2 gen_yield_from_throw3 generator1 generator2 generator_args generator_close generator_closure generator_exc generator_pend_throw generator_return generator_send'.split()}) # require yield
skip_tests.update({'basics/%s.py' % t for t in 'bytes_gen class_store_class globals_del string_join'.split()}) # require yield
skip_tests.update({'basics/async_%s.py' % t for t in 'def await await2 for for2 with with2'.split()}) # require yield
skip_tests.update({'basics/%s.py' % t for t in 'try_reraise try_reraise2'.split()}) # require raise_varargs