Re: [Babel] [Bug] Cache

[Eric Schulte <schulte.eric@gmail.com>]

"Sebastien Vauban" <sva-news@mygooglest.com> writes:

> Hi Eric,
>
> Eric Schulte wrote:
>> "Sebastien Vauban" <sva-news@mygooglest.com> writes:
>>>
>>> IIRC, some time ago, a bug involving the computation of the hash (when
>>> option cache is enabled) and NoWeb code blocks. I remember that it had been
>>> fixed.
>>>
>>> However, the following example shows it's not (true anymore):
>>>
>>> --8<---------------cut here---------------start------------->8---
>>> #+PROPERTY: cache yes
>>>
>>> #+name: common-code
>>> #+begin_src R :eval no
>>> s <- "Hello"
>>> #+end_src
>>>
>>> #+begin_src R :noweb yes
>>> <<common-code>>
>>>
>>> print(s)
>>> #+end_src
>>>
>>> #+results[f472c44e64e310a6d06544dbdfba558a709873a7]:
>>> : Hello
>>> --8<---------------cut here---------------end--------------->8---
>>>
>>> Change the "common code" block: edit "Hello", for example, and you'll see
>>> that the evaluation of the other code block is not redone (like if the NoWeb
>>> code was not expanded for computing the hash). It stays printing "Hello".
>>
>> Could you git bisect this breakage to isolate the offending commit?
>
> I couldn't find any version where my ECM would work. Though, I was sure to have
> read comments about that problem -- I never used that situation myself in the
> past, so I just assumed it had been fixed in the meanwhile. It seems not.
>
> And here the post of Achim where he explains that problem:
>
>   ╭────
>   │ From: Achim Gratz <Stromeko@nexgo.de>
>   │ Subject: Re: [PATCH] * lisp/ob-core.el (org-babel-execute-src-block):
>   │ 	insert hash for silent results
>   │ Date: Sun, 10 Mar 2013 09:52:10 +0100 (38 weeks, 1 day, 6 hours ago)
>   │
>   │ [...]
>   │
>   │ But back to my earlier remark about the hash value actually being a
>   │ signature of the source block and not the result.  If I use noweb
>   │ references, the reference text is cached, not its expansion.
>   ╰────
>

In that thread we agreed that the expansion of no-web references
*should* be included in code blocks for hashing, but no-one has had the
time to implement this.

I believe this is still the case.

-- 
Eric Schulte
https://cs.unm.edu/~eschulte
PGP: 0x614CA05D