Re: [elpa] externals/osm 05ac461360: Bail out earlier if dependencies are missing

Re: [elpa] externals/osm 05ac461360: Bail out earlier if dependencies are missing

[Stefan Monnier]

>     Bail out earlier if dependencies are missing

Better not signal such errors when loading the file, since the file might
be loaded for all kinds of reasons beside running its code.  In some of
those cases it can get loaded in an Emacs batch session.


        Stefan

Re: [elpa] externals/osm 05ac461360: Bail out earlier if dependencies are missing

[Daniel Mendler]

On 5/10/22 23:00, Stefan Monnier wrote:
> Better not signal such errors when loading the file, since the file might
> be loaded for all kinds of reasons beside running its code.  In some of
> those cases it can get loaded in an Emacs batch session.

I agree that the global check is a code smell. In this case I don't
expect batch usage since we are talking about a mouse driven map
display. The alternative would be to replicate the check in all the
entry points to the package, the osm-mode, the autoloaded osm-*
commands, which would require more code.

Daniel

Re: [elpa] externals/osm 05ac461360: Bail out earlier if dependencies are missing

[Stefan Monnier]

Daniel Mendler [2022-05-11 00:07:31] wrote:
> On 5/10/22 23:00, Stefan Monnier wrote:
>> Better not signal such errors when loading the file, since the file might
>> be loaded for all kinds of reasons beside running its code.  In some of
>> those cases it can get loaded in an Emacs batch session.
> I agree that the global check is a code smell. In this case I don't
> expect batch usage since we are talking about a mouse driven map
> display.

Again, I'm not talking about running the code.  I'm talking about
loading the file.  E.g. loading the file in order to find out which
functions or variables it defines (this can happen for example during
completion of `C-h o`).

> The alternative would be to replicate the check in all the
> entry points to the package, the osm-mode, the autoloaded osm-*
> commands, which would require more code.

The "right" place for such checks is as soon as you know that you *will*
definitely encounter an error.

When the file is being loaded, you don't know yet that an error is
inevitable because you don't know yet whether the loaded code will
be called.


        Stefan

Re: [elpa] externals/osm 05ac461360: Bail out earlier if dependencies are missing

[Philip Kaludercic]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

> Daniel Mendler [2022-05-11 00:07:31] wrote:
>> On 5/10/22 23:00, Stefan Monnier wrote:
>
>> The alternative would be to replicate the check in all the
>> entry points to the package, the osm-mode, the autoloaded osm-*
>> commands, which would require more code.
>
> The "right" place for such checks is as soon as you know that you *will*
> definitely encounter an error.
>
> When the file is being loaded, you don't know yet that an error is
> inevitable because you don't know yet whether the loaded code will
> be called.

My understanding in this case is that the basic functionality of osm.el
requires efficient JSON parsing to be available.  Without this, the
package becomes "prohibitively slow" (at least according to bug#55278).

Perhaps it would be better to add a helper function that does the check
and issues an error/warning, and call this at all entry-points?