bug#18343: 24.4.50; REGRESSION: `help-echo' property is not added, so no tooltip or echo

bug#18343: 24.4.50; REGRESSION: `help-echo' property is not added, so no tooltip or echo

[Drew Adams]

emacs -Q

In *scratch*, evaluate this:

(add-text-properties 1 10 '(help-echo "FOOOOOOOOOOOOOOO"))

Put the mouse pointer over one of the first 10 chars.  There is no
tooltip.  `M-x tooltip-mode', to turn it off.  Put pointer over the char
again.  There is no echo-area echo.

`C-u C-x =' on one of the first 10 chars.  There is no `help-echo'
property.

Using `put-text-property' instead of `add-text-properties' 
gives the same result.

In Emacs 24.3 or a prior release there is no such problem.


In GNU Emacs 24.4.50.1 (i686-pc-mingw32)
 of 2014-08-15 on LEG570
Bzr revision: 117706 rgm@gnu.org-20140815043406-p5hbu97cbm7pulcn
Windowing system distributor `Microsoft Corp.', version 6.1.7601
Configured using:
 `configure --enable-checking 'CFLAGS=-O0 -g3' CPPFLAGS=-DGLYPH_DEBUG=1'

bug#18343: 24.4.50; REGRESSION: `help-echo' property is not added, so no tooltip or echo

[Eli Zaretskii]

> Date: Thu, 28 Aug 2014 09:22:43 -0700 (PDT)
> From: Drew Adams <drew.adams@oracle.com>
> 
> emacs -Q
> 
> In *scratch*, evaluate this:
> 
> (add-text-properties 1 10 '(help-echo "FOOOOOOOOOOOOOOO"))
> 
> Put the mouse pointer over one of the first 10 chars.  There is no
> tooltip.  `M-x tooltip-mode', to turn it off.  Put pointer over the char
> again.  There is no echo-area echo.
> 
> `C-u C-x =' on one of the first 10 chars.  There is no `help-echo'
> property.

Disable font-lock-mode, and help-echo works again as expected.

It sounds like font-lock overwrites the help-echo property.

bug#18343: 24.4.50; REGRESSION: `help-echo' property is not added, so no tooltip or echo

[Wolfgang Jenkner]

On Thu, Aug 28 2014, Drew Adams wrote:

> (add-text-properties 1 10 '(help-echo "FOOOOOOOOOOOOOOO"))
>
> Put the mouse pointer over one of the first 10 chars.  There is no
> tooltip.  `M-x tooltip-mode', to turn it off.  Put pointer over the char
> again.  There is no echo-area echo.
>
> `C-u C-x =' on one of the first 10 chars.  There is no `help-echo'
> property.

Just turn off font-lock-mode ;-)

Seriously, educated guess + vc-annotate gives:

Author: Stefan Monnier <monnier@iro.umontreal.ca>
Date:   Tue Apr 22 13:45:43 2014 -0400

    * lisp/emacs-lisp/lisp-mode.el (lisp--match-hidden-arg): New function.
    (lisp-el-font-lock-keywords-2, lisp-cl-font-lock-keywords-2): Use it.
    (lisp-mode-variables): Set font-lock-extra-managed-props.

@@ -466,10 +489,10 @@ font-lock keywords will not be case sensitive."
                lisp-cl-font-lock-keywords-2))
 	  nil ,keywords-case-insensitive nil nil
 	  (font-lock-mark-block-function . mark-defun)
+          (font-lock-extra-managed-props help-echo)
 	  (font-lock-syntactic-face-function
 	   . lisp-font-lock-syntactic-face-function)))
   (setq-local prettify-symbols-alist lisp--prettify-symbols-alist)
-  ;; electric
   (when elisp
     (setq-local electric-pair-text-pairs
                 (cons '(?\` . ?\') electric-pair-text-pairs)))

bug#18343: 24.4.50; REGRESSION: `help-echo' property is not added, so no tooltip or echo

[Drew Adams]

ez> Disable font-lock-mode, and help-echo works again as expected.
ez> It sounds like font-lock overwrites the help-echo property.

Yes.  It apparently just removes the property.

wj> Just turn off font-lock-mode ;-)
wj> Seriously, educated guess + vc-annotate gives:
wj>
wj> Author: Stefan Monnier <monnier@iro.umontreal.ca>
wj> Date:   Tue Apr 22 13:45:43 2014 -0400
    ...
wj> + (font-lock-extra-managed-props help-echo)

I hope no one is suggesting that this is a new feature, instead
of a regression. ;-)

bug#18343: 24.4.50; REGRESSION: `help-echo' property is not added, so no tooltip or echo

[Wolfgang Jenkner]

On Thu, Aug 28 2014, Drew Adams wrote:

> wj> + (font-lock-extra-managed-props help-echo)
>
> I hope no one is suggesting that this is a new feature, instead
> of a regression. ;-)

This is emacs: we'll end up with a font-lock-help-echo text property.

bug#18343: 24.4.50; REGRESSION: `help-echo' property is not added, so no tooltip or echo

[Drew Adams]

> > wj> + (font-lock-extra-managed-props help-echo)
> >
> > I hope no one is suggesting that this is a new feature,
> > instead of a regression. ;-)
> 
> This is emacs: we'll end up with a font-lock-help-echo text
> property.

Sorry, I cannot tell whether you are joking, Wolfgang.  I hope so.

bug#18343: 24.4.50; REGRESSION: `help-echo' property is not added, so no tooltip or echo

[Lars Ingebrigtsen]

Drew Adams <drew.adams@oracle.com> writes:

> ez> Disable font-lock-mode, and help-echo works again as expected.
> ez> It sounds like font-lock overwrites the help-echo property.
>
> Yes.  It apparently just removes the property.

If you insert text with text properties into buffers controlled by
font-lock, they are removed.  (Most of them.)  So this isn't a bug.

Closing.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#18343: 24.4.50; REGRESSION: `help-echo' property is not added, so no tooltip or echo

[Drew Adams]

> > ez> Disable font-lock-mode, and help-echo works again as expected.
> > ez> It sounds like font-lock overwrites the help-echo property.
> >
> > Yes.  It apparently just removes the property.
> 
> If you insert text with text properties into buffers controlled by
> font-lock, they are removed.  (Most of them.)  So this isn't a bug.
> 
> Closing.

You are just saying that this is not a bug because it exists.

And it is certainly NOT the case that font-lock removes text
properties in general.  NOT "most" of them - there are an
unlimited number of text properties you can use, and
`font-lock-extra-managed-props' targets very few of them
(thank goodness).

The question is not whether `font-lock-extra-managed-props',
in effect, removes text properties, but why it now removes
THIS property, which has nothing to do with text highlighting.

Why should `help-echo' be on `font-lock-extra-managed-props'?
Why should toggling `font-lock-mode' toggle help-echo display?

Without hearing a solid argument in its favor, I do not see
this as a feature, but a bug (regression).

And if it is argued that it is a feature (I'd love to hear
the rationale), I see nothing about this incompatible change
in NEWS (e.g. for 24.4).

bug#18343: 24.4.50; REGRESSION: `help-echo' property is not added, so no tooltip or echo

[Michael Heerdegen]

Drew Adams <drew.adams@oracle.com> writes:

> Why should `help-echo' be on `font-lock-extra-managed-props'?

I guess the reason is to allow font-lock to propertize parts of the
buffer with this property.  This issue is a (presumably not trivially
avoidable) side effect.


Michael.

bug#18343: 24.4.50; REGRESSION: `help-echo' property is not added, so no tooltip or echo

[Drew Adams]

> > Why should `help-echo' be on `font-lock-extra-managed-props'?
> 
> I guess the reason is to allow font-lock to propertize parts of the
> buffer with this property.  This issue is a (presumably not trivially
> avoidable) side effect.

By "allow font-lock to propertize parts of the buffer with this
property" do you mean allow it to propertize, with faces, parts
of the buffer that happen to have property `help-echo'?  Or do
you mean allow it to add property `help-echo' parts of the buffer?

If the latter, what is the use case for font-lock doing that?

I'll assume you meant the former -

In that case, why not trivially avoidable?  Why not tell font-lock
hands-off this property, which has nothing to do with highlighting?
Until the recent change that caused this regression, property
`help-echo' was not on the list `font-lock-extra-managed-props'.

Is it clear to you why it needs to be on that list?  It's not
clear to me.

bug#18343: 24.4.50; REGRESSION: `help-echo' property is not added, so no tooltip or echo

[Eli Zaretskii]

> Date: Sun, 1 May 2016 08:52:58 -0800 (GMT-08:00)
> From: Drew Adams <drew.adams@oracle.com>
> Cc: Lars Ingebrigtsen <larsi@gnus.org>, 18343@debbugs.gnu.org
> 
> Why not tell font-lock hands-off this property, which has nothing to
> do with highlighting?

See lisp-mode.el for one answer.

bug#18343: 24.4.50; REGRESSION: `help-echo' property is not added, so no tooltip or echo

[Drew Adams]

> > Why not tell font-lock hands-off this property, which has nothing to
> > do with highlighting?
> 
> See lisp-mode.el for one answer.

Too unclear.  What part of that library do you think is
significant here?  What's your point?

(And what does `help-echo' have to do with Lisp mode,
necessarily?)

bug#18343: 24.4.50; REGRESSION: `help-echo' property is not added, so no tooltip or echo

[Michael Heerdegen]

Drew Adams <drew.adams@oracle.com> writes:

> By "allow font-lock to propertize parts of the buffer with this
> property" do you mean allow it to propertize, with faces, parts
> of the buffer that happen to have property `help-echo'?  Or do
> you mean allow it to add property `help-echo' parts of the buffer?
>
> If the latter, what is the use case for font-lock doing that?
>
> I'll assume you meant the former -

No, the latter.  As Eli suggested, see lisp-mode.el for examples.  Or
`font-lock-compile-keywords'.


Michael.

bug#18343: 24.4.50; REGRESSION: `help-echo' property is not added, so no tooltip or echo

[Michael Heerdegen]

Drew Adams <drew.adams@oracle.com> writes:

> Too unclear.  What part of that library do you think is
> significant here?  What's your point?

Just grep for "help-echo", all matches are related in an obvious way (or
don't you get matches with your version of the sources?).


Michael.

bug#18343: 24.4.50; REGRESSION: `help-echo' property is not added, so no tooltip or echo

[Eli Zaretskii]

> Date: Sun, 1 May 2016 10:22:05 -0700 (PDT)
> From: Drew Adams <drew.adams@oracle.com>
> Cc: michael_heerdegen@web.de, larsi@gnus.org, 18343@debbugs.gnu.org
> 
> > > Why not tell font-lock hands-off this property, which has nothing to
> > > do with highlighting?
> > 
> > See lisp-mode.el for one answer.
> 
> Too unclear.  What part of that library do you think is
> significant here?  What's your point?

Search for help-echo, and you will see.

> (And what does `help-echo' have to do with Lisp mode,
> necessarily?)

You will see.