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Date: Mon, 07 Nov 2016 07:45:00 -0000
From: Jan Kratochvil <jan.kratochvil@redhat.com>
To: Tom Tromey <tom@tromey.com>
Cc: gdb-patches@sourceware.org
Subject: Re: [RFA 01/14] Introduce py-ref.h
Message-ID: <20161107074548.GA28389@host1.jankratochvil.net>
References: <1478497656-11832-1-git-send-email-tom@tromey.com> <1478497656-11832-2-git-send-email-tom@tromey.com>
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On Mon, 07 Nov 2016 06:47:23 +0100, Tom Tromey wrote:
> +  /* Copy another instance.  */
> +  gdbpy_reference &operator= (const gdbpy_reference &other)
> +  {
> +    Py_XDECREF (m_obj);
> +    m_obj = other.m_obj;
> +    if (m_obj != NULL)
> +      Py_INCREF (m_obj);
> +    return *this;
> +  }
> +
> +  /* Transfer ownership from another instance.  */
> +  gdbpy_reference &operator= (gdbpy_reference &&other)
> +  {
> +    Py_XDECREF (m_obj);
> +    m_obj = other.m_obj;
> +    other.m_obj = NULL;
> +    return *this;
> +  }

These two methods stale-reference / deallocate during self-assignments:
  gdbpyref = gdbpyref;
  gdbpyref = std::move (gdbpyref);

std::unique_ptr<> and std::shared_ptr<> behave correctly in such cases.


Jan