ubuntu 20.04 or macos catalina running docker engine 20.10.2 and python 3.8.6
I've come across examples where calling `pyarrow.compute.replace_substring_regex` caused a segfault once using the result. After some experimentation, I found that the problem lies in the offsets buffer in the result of the computation.
Here is a docker file that reproduces the problem in a few lines (though without an immediate crash):
FROM python:3.8 RUN pip install pyarrow RUN echo "import pyarrow; \ import pyarrow.compute; \ options = pyarrow.compute.ReplaceSubstringOptions('a', ''); \ values = [''] * 16; \ arr = pyarrow.array(values, pyarrow.string()); \ res = pyarrow.compute.replace_substring_regex(arr, options=options); \ offsets = res.buffers(); \ assert any(offset != 0 for offset in offsets[-4:]);" > /test.py RUN python /test.py
The docker image installs pyarrow (4.0.0 at the time of submitting this issue), and then runs python code which creates an array of 16 empty strings, and calls `replace_substring_regex` on the array.
The offsets buffer's last 4 bytes (representing the last offset) are checked to be non-zero, which fails.
Everything but the last offset looks fine: the valid buffer, the rest of the offsets, and the data buffer.
I have more elaborate examples of arrays which return a random value for the last offset, causing crashes sooner than simply 0 at the end.
Another hint which might help, the problem occurs at multiples of 16, i.e. changing 16 to 32, 48, etc. still shows the problem, but other values don't have a problem.
When I cloned the latest master, built arrow, and run the example - there was no problem. But since I didn't see the issue here on JIRA, I thought I should probably post it. I have no idea if I'm building correctly, and maybe I'm adding a bug to a bug
- is superceded by
ARROW-12774 [C++][Compute] replace_substring_regex() creates invalid arrays => crash