Subject: bug#38406: 27.0.50; post-self-insert-hook does not hold its contract in cc-mode derived modes

From: Dmitry Gutov <[email-masked]>
Date: Wed, 4 Dec 2019 23:04:27 +0200

On 04.12.2019 22:41, Alan Mackenzie wrote:
> +(defvar c--unsafe-post-self-insert-hook-functions
> +  '(smie-blink-matching-open
> +    electric-pair-post-self-insert-function
> +    blink-paren-post-self-insert-function
> +    electric-indent-post-self-insert-function
> +    electric-layout-post-self-insert-function
> +    electric-quote-post-self-insert-function)
> +    "Known unsafe functions when members of `post-self-insert-hook' in CC Mode")

I don't see how filtering out a bunch of popular consumers of 
post-self-insert-hook can make it "act as per its contract again".

More surprisingly, what did smie-blink-matching-open and 
blink-paren-post-self-insert-function ever do so wrong? Neither of them 
modifies the buffer's contents.