bug#34294: 27.0.50; flymake-start-on-save-buffer has no effect

[Juri Linkov <juri@linkov.net>]

>> 4. Also I found these related entries in the same etc/TODO file:
>>
>>   ** Display something in the margin on lines that have compilation
>>   errors.
>
> Flymake does this, even though it uses the fringe by default, but I
> don't have more clues to what the author of this line intended.

I guess this is exactly what Flymake already does.

>> What do you think about displaying a tooltip on the fringe indicator
>> with the same text that is displayed on the tooltip over the location
>> of the error in the source buffer?  It's easier to hover on the fringe
>> than finding the location in the buffer to hover.
>
> I don't have any strong opinion. It's fine, I guess, but not
> specifically tied to Flymake.  It may be difficult to implement.

Yes, this is a more general feature.  I could look at how easy it
would be to implement, and later to use in Flymake.

> BTW you can use flymake-goto-next-error and flymake-goto-prev-error to
> navigate between errors, it's what I use all the time.

Thanks for the suggestion.  I could also look how easy to integrate
flymake-goto-next-error into the more general next-error framework that
provides easy to type keybindings.

> So to summarize, it'd be great if you could provide the three patches to
> implement the suggestions you gave.

OK, I'll provide these three patches.  But first please look at my feedback
on your suggestion to set flymake-no-changes-timeout to nil: after trying it,
I see that it helps me, but also it requires setting
flymake-start-syntax-check-on-newline to nil, because otherwise
syntax check is started on an unsaved buffer when yanking text
that contains newlines.