Branch: refs/heads/master Home: https://github.com/scikit-learn/scikit-learn Commit: 12c5ce25e885cded5d0d2beaae7589b878ed8672 https://github.com/scikit-learn/scikit-learn/commit/12c5ce25e885cded5d0d2bea... Author: shenhanc78 Date: 2018-01-17 (Wed, 17 Jan 2018) Changed paths: M sklearn/tree/_splitter.pyx Log Message: ----------- FIX properly handle corner case. (#10450) There is one test case that fails undefined behavior test. This happens when n is 0, which resutls in log(n) evalutes to -inf. And to convert -inf to integer is undefined behavior and causes exception when undefined behavior check is turned on. Properly handle this by early return when sorting array is zero length. I agree this might be an usage error instead of a bug, but to leave it vulnerable to undefined behavior exception might not a good idea. Undefined behavior check is happy after this fix.