This check for code_state->ip being NULL was added in
a7c02c4538 with a commit message that "When
generator raises exception, it is automatically terminated (by setting its
code_state.ip to 0)". It was also added without any tests to test for this
particular case. (The commit did mention that CPython's test_pep380.py
triggered a bug, but upon re-running this test it did not show any need for
this NULL check of code_state->ip.)
It is true that generators that have completed (either by running to their
end or raising an exception) set "code_state.ip = 0". But there is an
explicit check at the start of mp_obj_gen_resume() to return immediately
for any attempt to resume an already-stopped generator. So the VM can
never execute a generator with NULL ip (and this was true at the time of
the above-referenced commit).
Furthermore, the other parts of the VM just before and after this piece
of code do require (or at least assume) code_state->ip is non-NULL.
Signed-off-by: Damien George <damien@micropython.org>
63 KiB
63 KiB