patch 9.0.2123: Problem with initializing the length of range() lists Commit: https://github.com/vim/vim/commit/df63da98d8dc284b1c76cfe1b17fa0acbd6094d8 Author: Christian Brabandt <cb@256bit.org> Date: Thu Nov 23 20:14:28 2023 +0100 patch 9.0.2123: Problem with initializing the length of range() lists Problem: Problem with initializing the length of range() lists Solution: Set length explicitly when it shouldn't contain any items range() may cause a wrong calculation of list length, which may later then cause a segfault in list_find(). This is usually not a problem, because range_list_materialize() calculates the length, when it materializes the list. In addition, in list_find() when the length of the range was wrongly initialized, it may seem to be valid, so the check for list index out-of-bounds will not be true, because it is called before the list is actually materialized. And so we may eventually try to access a null pointer, causing a segfault. So this patch does 3 things: - In f_range(), when we know that the list should be empty, explicitly set the list->lv_len value to zero. This should happen, when start is larger than end (in case the stride is positive) or end is larger than start when the stride is negative. This should fix the underlying issue properly. However, - as a safety measure, let's check that the requested index is not out of range one more time, after the list has been materialized and return NULL in case it suddenly is. - add a few more tests to verify the behaviour. fixes: #13557 closes: #13563 Co-authored-by: Tim Pope <tpope@github.com> Signed-off-by: Christian Brabandt <cb@256bit.org>