esup byte compile warnings

esup byte compile warnings

[Serghei Iakovlev]

Hello,

There are `esup' [1] byte compile warnings I would like avoid to.
Some of them seems trivial to me.  However, I don't quite understand
slots related warnings.  In general I would like to realize on how
to deal with such kind of warnings and I need help.  In fact, I
often come across something similar and I'll appreciate it if you
help me deal with such warnings.

N.B. This happens in Emacs 28.0.50 as well as in 27.0.60

[1]: https://github.com/jschaf/esup/issues/68

-- 
Serghei

Re: esup byte compile warnings

[Stefan Monnier]

> There are `esup' [1] byte compile warnings I would like avoid to.
> Some of them seems trivial to me.  However, I don't quite understand
> slots related warnings.

The the slots, usually it's just that code that uses EIEIO seems to
misuse a weird feature of EIEIO, so they use the initval keyword instead
of the slot name when accessing the slot.  For example, often code will
do

    (slot-value x :file)

where the slot's name is not `:file` but `file`, so the correct usage is

    (slot-value x 'file)

This odd usage does work for historical reasons but is deprecated, hence
the warning.


        Stefan

Re: esup byte compile warnings

[Serghei Iakovlev]

I've replaced all the ‘oref’ with ‘slot-value’ and properly used
quotes for the slot names.  Thus, I've replaced

 (oref x :y)

by

 (slot-value x 'y)

This seems is works, but still there are some warnings remaining.
For example:

 In esup-total-exec-time:
 esup.el:166:52: Warning: Unknown slot ‘exec-time’

 In esup-total-gc-number:
 esup.el:172:52: Warning: Unknown slot ‘gc-number’

 In esup-total-gc-time:
 esup.el:178:50: Warning: Unknown slot ‘gc-time’

 In esup-drop-insignificant-times:
 esup.el:186:39: Warning: Unknown slot ‘exec-time’
 esup.el:530:25: Warning: Unknown slot ‘file’
 esup.el:538:9: Warning: Unknown slot ‘start-point’
 esup.el:545:30: Warning: Unknown slot ‘line-number’
 esup.el:548:30: Warning: Unknown slot ‘exec-time’
 esup.el:546:30: Warning: Unknown slot ‘percentage’
 esup.el:549:30: Warning: Unknown slot ‘expression-string’

 In esup-fontify-results:
 esup.el:560:15: Warning: Unknown slot ‘expression-string’

Consider the following defun:

 (defun esup-total-exec-time (results)
   "Calculate the total execution time of RESULTS."
   (cl-loop for result in results
            sum (slot-value result 'exec-time) into total-exec-time
            finally return total-exec-time))

This produces a waring:

 In esup-total-exec-time:
 esup.el:166:52: Warning: Unknown slot ‘exec-time’

Looks like the reason is that the byte-compiler unable to match
‘result’ with the class declaration.

I found similar [1] issues [2], but I'm still not pretty sure the
proper way to fix these warnings.

[1]: https://lists.gnu.org/archive/html/emacs-devel/2017-01/msg00678.html
[2]: https://lists.gnu.org/archive/html/emacs-devel/2016-02/msg00880.html

> On 24 Jan 2020, at 23:55, Stefan Monnier <monnier@iro.umontreal.ca> wrote:
> 
> 
>> There are `esup' [1] byte compile warnings I would like avoid to.
>> Some of them seems trivial to me.  However, I don't quite understand
>> slots related warnings.
> 
> The the slots, usually it's just that code that uses EIEIO seems to
> misuse a weird feature of EIEIO, so they use the initval keyword instead
> of the slot name when accessing the slot.  For example, often code will
> do
> 
>    (slot-value x :file)
> 
> where the slot's name is not `:file` but `file`, so the correct usage is
> 
>    (slot-value x 'file)
> 
> This odd usage does work for historical reasons but is deprecated, hence
> the warning.
> 
> 
>        Stefan
> 
> 

Re: esup byte compile warnings

[Stefan Monnier]

> Consider the following defun:
>
>  (defun esup-total-exec-time (results)
>    "Calculate the total execution time of RESULTS."
>    (cl-loop for result in results
>             sum (slot-value result 'exec-time) into total-exec-time
>             finally return total-exec-time))
>
> This produces a waring:
>
>  In esup-total-exec-time:
>  esup.el:166:52: Warning: Unknown slot ‘exec-time’

This warning means that the bytecompiler has not seen any `defclass`
that defines a slot `exec-time`.  Maybe it's perfectly normal (you know
that the object will indeed have an `exec-time` slot when that code will
be executed), e.g. because the object will be created in another file
which is not `require`d in this file, but without knowing more about
this slot it's hard to tell what's the best way to address the warning.

[...looking at https://github.com/jschaf/esup...]

Oh, I think it's because of

    (let ((load-path (append load-path (list esup-load-path))))
      (require 'esup-child))

which means that the `require` won't be executed by the byte-compiler
(because it's within a `let`).  Either you should just drop this
`load-path` trickery (and push the responsability of `load-path`
manipulation to the code that byte-compiles the files, as usual), or you
may want to wrap this within an `eval-and-compile`.

> Looks like the reason is that the byte-compiler unable to match
> ‘result’ with the class declaration.

The compiler doesn't even try to infer types.  It only checks that some
class somewhere has defined a slot of that name (that's good enough to
catch most typos).


        Stefan


PS: While I'm here I noticed:

    (eval-when-compile
      (if (and (<= emacs-major-version 24)
               (<= emacs-minor-version 3))
          (require 'cl)
        (require 'cl-lib)))

which makes no sense: those two libraries provide the same *kind* of
functionality, but under completely different names.  The rest of the
code uses things like `cl-loop`, so you need to (require 'cl-lib)
because that's what the code uses.  In Emacs<24.4, `cl-lib` will itself
load `cl` (because it uses it internally, but that's an implementation
detail).

Re: esup byte compile warnings

[Serghei Iakovlev]

> Oh, I think it's because of
> 
>    (let ((load-path (append load-path (list esup-load-path))))
>      (require 'esup-child))
> 

Good catch!  Thank you.  Actually I planned to remove this earlier
but didn't noticed this relation.

> PS: While I'm here I noticed:
> 
>    (eval-when-compile
>      (if (and (<= emacs-major-version 24)
>               (<= emacs-minor-version 3))
>          (require 'cl)
>        (require 'cl-lib)))
> 
> which makes no sense: those two libraries provide the same *kind* of
> functionality, but under completely different names.  The rest of the
> code uses things like `cl-loop`, so you need to (require 'cl-lib)
> because that's what the code uses.  In Emacs<24.4, `cl-lib` will itself
> load `cl` (because it uses it internally, but that's an implementation
> detail).
> 

Yes, this is fixed in the separated branch (‘byte-war’) which I have
not yet merged into master.