[ARROW-12893] [Python] Slicing array can lead to negative length

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• External issue URL: https://github.com/apache/arrow/issues/28623
• Assignee: Alessandro Molina
• Reporter: Alessandro Molina
• Created: 27/May/21 14:14
• Updated: 11/Jan/23 08:29
• Resolved: 12/Jul/21 13:30

Description

Slice an arrow array can lead to a negative length, when instead it should never be smaller than 0.

arr = pa.array(range(10))
assert len(arr[-9:-20]) == 0

Array.length() returns -1 which makes the previous snippet crash as Python never accepts length < 0

In particular if you have Python in debug mode it will explicitly fail the related assertion
Assertion failed: (len >= 0 || PyErr_Occurred()), function PyObject_Size, file Objects/abstract.c, line 61

Issue Links

• is a clone of: ARROW-12769 [Python] Negative out of range slices yield invalid arrays