[ARROW-12837] [C++] Array::ToString() segfaults with null buffer.

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 4.0.0
• Fix Version/s: 6.0.0
• Component/s: C++
• Labels: pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/28571
• Assignee: Alessandro Molina
• Reporter: Alessandro Molina
• Created: 20/May/21 14:27
• Updated: 11/Jan/23 08:29
• Resolved: 27/Jul/21 11:45

Description

In some tests in the Arrow test suite there are cases where arrays are made without allocating real buffers of data, using Buffer of length 0 and with nullptr as their data.

In this cases the Array::ToString() does lead to segfault, at least for Int arrays.

* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x0)
    frame #0: 0x0000000101dac696 libarrow.500.dylib`std::__1::enable_if<is_integer_type<arrow::NumericArray<arrow::Int32Type>::TypeClass>::value, arrow::Status>::type arrow::ArrayPrinter::WriteDataValues<arrow::NumericArray<arrow::Int32Type> >(this=0x00007ffeefbfea98, i=0)::'lambda'(long long)::operator()(long long) const at pretty_print.cc:152:73
   149 	  enable_if_integer<typename T::TypeClass, Status> WriteDataValues(const T& array) {
   150 	    const auto data = array.raw_values();
   151 	    // Need to upcast integers to avoid selecting operator<<(char)
-> 152 	    WriteValues(array, [&](int64_t i) { (*sink_) << internal::UpcastInt(data[i]); });
   153 	    return Status::OK();
   154 	  }
   155 	 

The issue can probably be worked around by checking if the data in the array is valid (at least for the most obvious cases, like NULLS or 0-length data) when building the string representation

Issue Links

• links to: GitHub Pull Request #10713