I believe (fboundp 'flymake-diagnostics) is a simple and effective enough
check.

Incidentally, I don't know what elpy does in regards to syntax checking,
but it might have been completely or partially superseded by the new
flymake python backend.

On Fri, Apr 27, 2018, 14:35 Da Zhang <zhangda82@gmail.com> wrote:

> Hi Joao,
>
> I tried your suggested solution and it worked beautifully. Is there a way
> to check if the new mechanism of flymake-diagnostics etc are available?
>
> I am working with the maintainer of elpy to update the function
> "elpy-flymake-error-at-point", and ideally we want to see if the new
> mechanism is available.
>
> Thanks in advance!
>
> Da
>
> On 2018-04-26 5:25 AM, João Távora wrote:
>
> Da Zhang <zhangda82@gmail.com> <zhangda82@gmail.com> writes:
>
>
> Hello --
>
> I am a long term Emacs user and I use flymake together with flymake-cursor on a daily basis.
>
> Starting Emacs 26.1, I noticed that flyamke was redesigned and no
> longer has the var flymake-err-info that contains the error info
> reported by the backend syntax checker.
>
> This makes flymake-cursor and code like the following not work:
>
> (defun elpy-flymake-error-at-point ()
>   "Return the flymake error at point, or nil if there is none."
>   (when (boundp 'flymake-err-info)
>     (let* ((lineno (line-number-at-pos))
>            (err-info (car (flymake-find-err-info flymake-err-info
>                                                  lineno))))
>       (when err-info
>         (mapconcat #'flymake-ler-text
>                    err-info
>                    ", ")))))
>
> I believe this is a potential issue and wonder if someone could direct
> me to any alternatives to flymake-err-info in the newly designed
> flyamke.
>
>
> Hi Da Zhang,
>
> I'm the responsible for the redesign. Although I tried to keep *some*
> backward compatibility to old flymake.el's API, the truth is that *all*
> of it was an API.
>
> The bad news is that this variable is gone: it couldn't be
> backward-adapted. The good news is that it should be much easier to
> write your function:
>
> (defun elpy-flymake-error-at-point ()
>   "Return the flymake error at point, or nil if there is none."
>   (mapconcat #'flymake-diagnostic-text (flymake-diagnostics (point)) "\n"))
>
> Notice that, to keep with the protocol, this returns a concatenation of
> the text strings of all the errors at point. You might be better served
> by returning and manipulating the objects returned by
> flymake-diagnostics instead.
>
> See section "2.2.1 Flymake utility functions" of the Flymake manual
> bundled with Emacs for more information.
>
> I don't know what flymake-cursor does, but I suspect it can be fixed
> accordingly.
>
> Hope this helps,
> João
>
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