[ARROW-17938] [Python][CI] python_test.cc build failure

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 10.0.0
• Component/s: Continuous Integration, Python
• External issue URL: https://github.com/apache/arrow/issues/33146
• Assignee: Antoine Pitrou
• Reporter: Antoine Pitrou
• Created: 05/Oct/22 08:27
• Updated: 11/Jan/23 11:57
• Resolved: 05/Oct/22 13:35

Description

Just saw this on Crossbow CI, for example on the conda-linux-gcc-py39-cuda job:

2022-10-04T12:24:11.3370140Z /build/arrow-cpp-ext_1664884270503/work/python/pyarrow/src/python_test.cc:116:5:   required from here
2022-10-04T12:24:11.3372155Z /build/arrow-cpp-ext_1664884270503/_h_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_pla/include/arrow/util/string_builder.h:49:10: error: ambiguous overload for 'operator<<' (operand types are 'std::ostream {aka std::basic_ostream<char>}' and 'std::nullptr_t')
2022-10-04T12:24:11.3373600Z    stream << head;
2022-10-04T12:24:11.3374077Z    ~~~~~~~^~~~~~~