[O] Bug: Infinite recursion in org-babel-get-src-block-info [9.1.13 (9.1.13-elpaplus @ mixed installation!

[Tobias Zawada]

I mostly cite here from https://emacs.stackexchange.com/q/41208/2370:

The following example causes an infinite recursion in 
~org-babel-get-src-block-info~.

#+BEGIN_SRC org
,#+BEGIN_SRC org
,#+NAME: add3
,#+BEGIN_SRC elisp :var num=0
(+ 3 num)
,#+END_SRC


,* Use function drawer header arg
:PROPERTIES:
:header-args: :var n=add3(5)
:END:


,#+NAME: whatIsN
,#+BEGIN_SRC sh
echo $n
,#+END_SRC


,#+RESULTS: whatIsN
: 8


,#+BEGIN_SRC sh :var a=whatIsN
echo $a
,#+END_SRC
#+END_SRC

The problem is located in org-babel-get-src-block-info.


The function org-babel-params-from-properties is used there. Its doc-string is:


Retrieve parameters specified as properties. Return a list of association lists 
of source block params specified in the properties of the current outline entry.


But they do not say what the current outline entry is. In 
org-babel-get-src-block-info they assumed that the current outline entry would 
be that one at point but org-babel-params-from-properties uses also 
org-babel-current-src-block-location to retrieve parameters from there.


Even if (point) is 1 for the first source block add3 the variable 
org-babel-current-src-block-location in org-babel-params-from-properties points 
to the source block whatIsN.


So not the header-args for add3 are collected by 
org-babel-params-from-properties but those of whatIsN.


The consequence is that add3 gets the header arg n=add3(5) from the drawer. 
Naturally, that leads to infinite recursion.


The funny thing is that they already tried to make sure that 
org-babel-params-from-properties gets the right header args from the location 
of datum. I cite a small section of org-babel-get-src-block-info:


;; If DATUM is provided, make sure we get node
 ;; properties applicable to its location within
 ;; the document.
 (org-with-point-at (org-element-property :begin datum)
 (org-babel-params-from-properties lang))


You can avoid the error if you additionally let-bind 
org-babel-current-src-block-location to the location of datum:


;; If DATUM is provided, make sure we get node
 ;; properties applicable to its location within
 ;; the document.
 (let ((org-babel-current-src-block-location (org-element-property :begin 
datum)))
 (org-with-point-at org-babel-current-src-block-location
 (org-babel-params-from-properties lang)))


I am not sure about the full consequences of that change through.