BUG: Loadtxt should pass `checkref=False` to resize to avoid problems when tracing

numpy version: 1.14.3 python version: 3.6.5

This was originally reported in https://github.com/Microsoft/ptvsd/issues/465 (error was on numpy.loadtxt, but the real issue lies in resize itself).

A sample to reproduce is:

import sys

def trace_dispatch(frame, event, arg):
    return trace_dispatch

sys.settrace(trace_dispatch)

def method():
    import numpy
    Y = numpy.array([1] * 10, numpy.float32)
    Y.resize([20, 20])

method()

When Y.resize() is reached, the following error is thrown:

ValueError: cannot resize an array that references or is referenced
by another array in this way.  Use the resize function.

So, it seems it’s that way by design, but this also means that by design, any function which calls array.resize is not traceable (which I don’t think is expected).

[fabioz]

Seems a reasonable tradeoff to me (although if it’s really important, I’d say that it should be True when running numpy tests to make sure that some future contributor won’t add a new reference to the array by mistake inside numpy.loadtxt).

[mattip]

Fixed in #10737, which is part of the 1.15 release

refcheck=True in tests must be inside a if HAS_REFCOUNT block since refcheck=True will raise an exception on PyPy, it has no refcount semantics.