help-fns unsolicited elisp loading (was Re: bug#28048: 26.0.50; behaviour of C-h f semantic-mode)

help-fns unsolicited elisp loading (was Re: bug#28048: 26.0.50; behaviour of C-h f semantic-mode)

[Mark Oteiza]

On 12/08/17 at 01:47am, npostavs@users.sourceforge.net wrote:
> Mark Oteiza <mvoteiza@udel.edu> writes:
> 
> > Is there a bug associated with the new C-h f behaviour?
> 
> No, it was introduced on emacs-devel, see [1] and followups.
> 
> [1]: http://lists.gnu.org/archive/html/emacs-devel/2016-05/msg00441.html

Now I know why I'd get seemingly random messages about MH-E not being
present on my system.

https://git.savannah.gnu.org/cgit/emacs.git/commit/?id=fd8084aaf9

Why are we loading (effectively) arbitrary elisp without the user asking
for it?  Any elisp in Emacs--including installed 3rdp packages--can get
loaded when looking for function or variable help.  Further, loading
elisp can do anything, so a PoC is trivial.  Not even considering the
security part of it, I'm going to end up with way more stuff loaded,
potentially having more crap to sift through in apropos.  Please at the
very least disable this by default before it goes into a release.

For the record, the following init.el shim restores the previous
behavior:

(with-eval-after-load "help-fns"
  (defun my-obarray (string pred action)
    (complete-with-action action obarray string pred))
  (fset 'help--symbol-completion-table 'my-obarray))

Re: help-fns unsolicited elisp loading (was Re: bug#28048: 26.0.50; behaviour of C-h f semantic-mode)

[Noam Postavsky]

On Fri, Sep 22, 2017 at 12:09 AM, Mark Oteiza <mvoteiza@udel.edu> wrote:
> On 12/08/17 at 01:47am, npostavs@users.sourceforge.net wrote:
>> Mark Oteiza <mvoteiza@udel.edu> writes:
>>
>> > Is there a bug associated with the new C-h f behaviour?
>>
>> No, it was introduced on emacs-devel, see [1] and followups.
>>
>> [1]: http://lists.gnu.org/archive/html/emacs-devel/2016-05/msg00441.html
>
> Now I know why I'd get seemingly random messages about MH-E not being
> present on my system.
>
> https://git.savannah.gnu.org/cgit/emacs.git/commit/?id=fd8084aaf9
>
> Why are we loading (effectively) arbitrary elisp without the user asking
> for it?  Any elisp in Emacs--including installed 3rdp packages--can get
> loaded when looking for function or variable help.

I believe it's only elisp included in Emacs proper that is eligible
for this lookup. The table is built during 'make autoloads'.

Re: help-fns unsolicited elisp loading (was Re: bug#28048: 26.0.50; behaviour of C-h f semantic-mode)

[Mark Oteiza]

On September 22, 2017 12:28:30 AM EDT, Noam Postavsky <npostavs@users.sourceforge.net> wrote:
>On Fri, Sep 22, 2017 at 12:09 AM, Mark Oteiza <mvoteiza@udel.edu>
>wrote:
>>
>> Why are we loading (effectively) arbitrary elisp without the user
>asking
>> for it?  Any elisp in Emacs--including installed 3rdp packages--can
>get
>> loaded when looking for function or variable help.
>
>I believe it's only elisp included in Emacs proper that is eligible
>for this lookup. The table is built during 'make autoloads'.

I have language modes installed via package-install-file that become loaded when doing C-h f on their mode functions, the same as what happens for things in Emacs proper. 

Re: help-fns unsolicited elisp loading (was Re: bug#28048: 26.0.50; behaviour of C-h f semantic-mode)

[Noam Postavsky]

On Sat, Sep 23, 2017 at 10:50 AM, Mark Oteiza <mvoteiza@udel.edu> wrote:
>>
>>I believe it's only elisp included in Emacs proper that is eligible
>>for this lookup. The table is built during 'make autoloads'.
>
> I have language modes installed via package-install-file that become loaded when doing C-h f on their mode functions, the same as what happens for things in Emacs proper.

Oh, I see, there is a register-definition-prefixes call in the
generated <package>-autoloads.el file.