<p dir="auto">It seems that the <a href="https://github.com/numpy/numpy/blob/master/doc/release/1.9.0-notes.rst#the-diagonal-and-diag-functions-return-readonly-views">promised</a> change of <code class="notranslate">diag</code>/<code class="notranslate">diagonal</code> to return a writeable view was forgotten in 1.10 and 1.11.</p>
<p dir="auto">Is the fix as easy as changing the flag on creation?</p>
<p dir="auto">The ndarray.diagonal method currently returns a view, but it is not writeable. It is documented to return a writeable view in 1.10.</p>