Re: [PATCH] ob-core: check argument to goto-char

[Eike <eike@eknet.org>]

Charles C. Berry <ccberry@ucsd.edu> writes:

> On Sat, 30 Apr 2016, Eike wrote:
>
>>
>> Hi,
>>
>> I have some code that uses `org-babel-insert-result' and I've found that
>> evaluating for example
>>
>>   (org-babel-insert-result "a")
>>
>> results in an error.
>
> Although not explicitly marked as such, `org-babel-insert-result' seems 
> intended as an internal function for processing babel RESULTs.

ok, I didn't know.


>> The reason is that `goto-char' is called with a nil
>> argument.
>
> When your snippet is in a src block or inline src block, there is no 
> error. Also, no error when point is in a src block and you run the snippet 
> with
>
> :  M-x eval-expression RET (org-babel-insert-result "a") RET
>
> So, it looks like you are trying to evaluate the snippet above when 
> point is not in a src block. AFAICS, there is no guarantee that such usage 
> will succeed.
>
> Failure in such uses seems more like a feature than a bug.

Ok, so it wasn't clear to me that point must be in a src block. Since
the results are passed as argument, I made the false assumption that it
inserts them where point currently is /or/ after a src block.

The lisp code at that point (ob-core.el l.2212) invokes goto-char with
nil which is caused by `inline' being nil. But the next line checks for
`inline' being nil as does the line before: (if existing-result
(goto-char existing-result) …) so I thought it might be good to check
for that in the else-branch, too.

>> I simply put the snippet in a `when' clause, but since the
>> function is quite large I'm not so sure if it's now doing always the
>> correct thing. At least my org files seem still to work….
>>
>> I've added the patch in case it is ok to be applied. Maybe someone can
>> have a look at it.
>>
>
> See http://orgmode.org/worg/org-contribute.html for details on how to 
> contribute. Also, running `make test' on new code is a good idea.
>
> If you can explain what you are trying to achieve, someone may suggest a 
> fix that does not require retooling babel internals.

I didn't really mean you to apply my patch, but rather have a look at
it: thanks for that. I thought it's simpler to send a patch file than to
explain in words… `make test' doesn't show unexpected failures to me,
did I miss something? I'm sorry for breaking any contributing
rules, I'll try to do better next time.

What I want to do: I want to insert an org table somewhere in an org
buffer. The data is not from an src block but retrieved from somewhere
else. So I have a list like `(("id" "num") hline ("a" "1") ("b" "2"))'
and I'd like to put it in a buffer as an org table (the buffer is in
org-mode).

It is certainly not my intention to retool babel internals to achieve
this. My impression was that this may be a bug. But it may not, that's
why I asking here.

Thanks
Eike

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