Re: [PATCH] Fixing a regression in org-persists ability to handle non-list container arguments.

[lra]

Hi Ihor and Karthik,

> Thanks!
> Applied, onto main.

> LRA, thanks for the fix.

Glad to be of assistance!

> P.S. We really need tests for org-persist.

Yeah I did note a couple of pretty straight-forward opportunities for
clean-up wrt. redundancies and readability, but without
regression-tests and lacking confidence that I understood everything I
thought it was best to keep the patch as simple as possible. I
would've felt pretty stupid if I accidentally introduced a new
regression in my regression-fix haha. I'll include some of the stuff
from my notes below in case it's of interest to anybody working on
org-persist.

I hope it isn't just noise and that it can be of use :)

Regards,
LRA

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(These are all relative to the org-latex-preview dev-branch and not
main, but I think all the code in question applies to both, just the
linenums might be off.)

1.
   I noticed when testing on upstream that there are a ton of
   redundant calls to `o-p--normalize-container' throughout the
   package. I saw that you've already dealt with the redundancy in
   your branch Karthik, so maybe it's unimportant but I think the
   redundant calls also just hurt readability somewhat. A couple
   cases of
#+begin_example elisp
(defun somefun (container ... )
  (let ((container (org-persist--normalize-container container))
    ... )))

;; And then every call will have
  ...
  (somefun (org-persist--normalize-container container))
  ...
#+end_example
   
2.
   The bits handling the shape of container in `o-p--add-to-index'
   and `o-p--remove-from-index' are both redundant, as all calls
   to these functions use containers read from the index or from
   `o-p--get-collection', in both cases there's already logic ensuring
   it's a list of lists. This change worked fine in my limited testing:

Replacing =lisp/org-persist.el:L576-9= and =L592-5=
#+begin_example elisp
        (dolist (cont (cons container container))
#+end_example

3.
   Maybe I'm just an idiot, but the use (or maybe just the name) of
   `o-p--get-collection' was a bit confusing to me, as it's used both
   to find and /create/ indices. E.g. this bit of logic in
   `o-p-register' was particularly confusing where it's used in a let
   /before/ a conditional that determines whether the assignment is
   actually used for anything.
   
=lisp/org-persist.el:L1006-8=
#+begin_example elisp
    (let ((collection (org-persist--get-collection container associated misc)))
      (when (and expiry (not inherit))
        (when expiry (plist-put collection :expiry expiry))))
#+end_example

   With the redundant inner `when', it reads a bit like the let was
   supposed to be between the two, which I think makes sense if the
   first condition is an `or' instead of `and'? Although I'm not sure
   I actually figured out how this function or the inherit keyword
   works.

4. 
> Ihor, `org-persist--find-index' is singularly confusing.  I've been over
> it with edebug a few times and still can't figure out what it's doing,
> because `container' means different things at different points in the
> function because of the macro `org-persist-collection-let'.  Could it be
> simplified in some way?

   I had the exact same confusion motivating my attempt at rewording
   the comment. On my machine and in my limited testing, dropping the
   second use of the macro completely  worked fine:

   Replacing =lisp/org-persist.el:L552-4=
#+begin_example elisp
                         (lambda (cont)
                             (member cont (plist-get r :container)))
#+end_example

5.
   Another way to simplify `o-p--find-index' (and I think also get
   pretty close to achieving full consistency on the container shape),
   would be to put this bit from the start of `o-p--get-collection' at
   the start of `-read', `-write-all' and `-unregister' (or maybe in a
   (if (not inner) .. ) at the end of `o-p--normalize-container'?):

#+begin_example elisp
(unless (and (listp container) (listp (car container)))
    (setq container (list container)))
#+end_example

   This would cover all calls to`o-p--find-index' and allow you to
   revert the changes in both my patch and 7fd80991c3 I think. This is
   sort-of what I was thinking of wrt. rewriting
   `o-p--normalize-container' in my original e-mail.

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