bug#13891: 24.3.50; highlight-regexp incorrectly retains partial state after buffer reversion

[Stefan Monnier]

>>> I noticed two things that show that partial highlight-regexp state
>>> lingers after calling revert-buffer, see items 9 and 12.  After buffer
>> I've installed the patch below which should fix those problems.
> (This is not a comment on the patch you have put in, but my initial
> thoughts as I investigated the bug.)
> I have a feeling that your fix is "inconsistent" with having
> `hi-lock-interactive-patterns' as `permanent-local'.

Agreed.  Even more so for hi-lock-file-patterns.

> With `global-hi-lock-mode' ON, you will notice that highlighting will
> be retained across reverts.

Not any more after my patch.

> 2. I think `font-lock-fontify-buffer' should be added to
>    `hi-lock-font-lock-hook'.

Why?

>    For some reason, `hi-lock-font-lock-hook' doesn't get called at all
>    (even though it is added to the `font-lock-mode-hook'.)

What was your test case?

>    Problem area: `font-lock-mode-hook' is not documented and I really
>    don't when it is getting called.

font-lock-mode is a normal minor-mode, so font-lock-mode-hook is called
at the end of running font-lock-mode (both to enable and to disable it).


        Stefan