Hi Anush,

Appreciate you reporting this.

Anush V <j@gnu.org> writes:

> steps to reproduce:
> emacs --no-init
> M-x erc
> ;; join some channel.
> M-x which-function-mode
>
> Current behavior:
> In erc buffers, which-function-mode displays either "[n/a]" or a string based on
> the chat history in the mode line.

FTR, I'm able to reproduce it.

> Expected behavior:
> which-function-mode shouldn’t be adding any string to mode line in erc buffers

The first of the attached patches should hopefully address the issue.

Thanks,
J.P.