Re: [PATCH] Fix Emacs-26 compatibility (was: Re: [BUG] org-element loading fails with "regexp" argument not "stringp")

[Ihor Radchenko <yantar92@posteo.net>]

Max Nikulin <manikulin@gmail.com> writes:

> On 05/07/2023 17:35, Ihor Radchenko wrote:
>> However, you will see many more failures with Emacs 26 on the latest
>> main.
>
> With the couple of attached patches the only failing test is
>
> ...
> Test test-org/delete-indentation condition:
>      (wrong-number-of-arguments
>       (0 . 1)
>       3)
>     FAILED   935/1069  test-org/delete-indentation

Yup, it is because `org-delete-indentation' now uses 3 arguments when
calling `delete-indentation', while in Emacs 26 `delete-indentation'
only accepted up to 1.

And there are many warnings of which I have clue about the origin.
Except `string-search' undefined, which is not yet available in Emacs 26.

> From 2f2d330e90b10a86aa6b3b9ff279bc012b339396 Mon Sep 17 00:00:00 2001
> From: Max Nikulin <manikulin@gmail.com>
> Date: Wed, 5 Jul 2023 22:50:44 +0700
> Subject: [PATCH 2/2] org-compat.el: Define `flatten-tree' for Emacs-26
>  compatibility
>
> * lisp/org-compat.el (flatten-tree): New compatibility function
> earlier used as `org-protocol-flatten'.
> * lisp/org-protocol.el (org-protocol-flatten): Remove the definition
> of the function.
> (org-protocol-flatten-greedy): Use `flatten-tree' instead of
> `org-protocol-flatten'.

You are removing `org-protocol-flatten' function, which is a breaking
change. We should leave an obsolete alias.

Also, you are defining `flatten-tree' function, which is outside Org's
namespace. We should better avoid it and use something like
`org-flatten-tree'.

-- 
Ihor Radchenko // yantar92,
Org mode contributor,
Learn more about Org mode at <https://orgmode.org/>.
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