From 6d2680fa36696fd0b2fd7a595f4a26153cd84e07 Mon Sep 17 00:00:00 2001 From: Damien George Date: Tue, 18 May 2021 00:23:13 +1000 Subject: [PATCH] py/objarray: Fix constructing a memoryview from a memoryview. Fixes issue #7261. Signed-off-by: Damien George --- py/objarray.c | 8 ++++++++ tests/basics/memoryview_gc.py | 10 ++++++++++ 2 files changed, 18 insertions(+) diff --git a/py/objarray.c b/py/objarray.c index be85674f87..16a4d4aac7 100644 --- a/py/objarray.c +++ b/py/objarray.c @@ -220,6 +220,14 @@ STATIC mp_obj_t memoryview_make_new(const mp_obj_type_t *type_in, size_t n_args, bufinfo.len / mp_binary_get_size('@', bufinfo.typecode, NULL), bufinfo.buf)); + // If the input object is a memoryview then need to point the items of the + // new memoryview to the start of the buffer so the GC can trace it. + if (mp_obj_get_type(args[0]) == &mp_type_memoryview) { + mp_obj_array_t *other = MP_OBJ_TO_PTR(args[0]); + self->memview_offset = other->memview_offset; + self->items = other->items; + } + // test if the object can be written to if (mp_get_buffer(args[0], &bufinfo, MP_BUFFER_RW)) { self->typecode |= MP_OBJ_ARRAY_TYPECODE_FLAG_RW; // indicate writable buffer diff --git a/tests/basics/memoryview_gc.py b/tests/basics/memoryview_gc.py index d366cbbb15..5cd6124ada 100644 --- a/tests/basics/memoryview_gc.py +++ b/tests/basics/memoryview_gc.py @@ -21,3 +21,13 @@ for i in range(100000): # check that the memoryview is still what we want print(list(m)) + +# check that creating a memoryview of a memoryview retains the underlying data +m = None +gc.collect() # cleanup from previous test +m = memoryview(memoryview(bytearray(i for i in range(50)))[5:-5]) +print(sum(m), list(m[:10])) +gc.collect() +for i in range(10): + list(range(10)) # allocate memory to overwrite any reclaimed heap +print(sum(m), list(m[:10]))