Re: [PATCH] ob-plantuml: Allow setting PlantUML args for jar file

[Max Nikulin <manikulin@gmail.com>]

Hi.

Disclaimer: I am neither plantuml nor ditaa user, so my comments may 
have no sense.

On 15/01/2022 13:20, Ihor Radchenko wrote:
> Dejan Josifović writes:
> 
>> Comparing ob-plantuml.el and plantuml-mode.el files I found what is the
>> problem. plantuml-mode has a customizable variable for specifying
>> arguments when using PlantUML from jar (plantuml-jar-args (list
>> "-charset" "UTF-8" ). The charset arguments is what is needed for
>> the images to render correctly (I confirmed it by implementing it locally).
>>
>> I was wondering why such variable doesn't exist in ob-plantuml.

Dejan, have you tried :java or :cmdline header arguments?

> Even though I was unable to reproduce your problem (most likely because
> my system is different), it sounds like a good idea to allow users to
> customise jar args as well.

I agree that arguments should be customizable when the application is 
launched from jar, but there are already :java argument that is inserted 
before jar file and :cmdline argument that is appended after it.

Another consideration is that ob-ditaa and ob-plantuml should use 
similar set of header arguments for additional parameters. They (and 
third-party packages) may even share some parameters related to java 
executable location and arguments for tuning of java VM (memory limits, 
etc.).

> See the attached patch. It appears that we can simply carry over the
> executable args to jar (but please test it on other systems!)

> -				(t (list java
> -					 "-Djava.awt.headless=true"

(unrelated to this patch) The line above is a recent change, and I do 
not see a reason why it is not added in a customizable way through 
appending (:java "-Djava.awt.headless=true") to 
`org-babel-default-header-args:plantuml'. Maybe I just missed something 
stupid since I have not tried it.

> -					 "-jar"
> -					 (shell-quote-argument (expand-file-name org-plantuml-jar-path))))))
> +				(t `(,java
> +				     "-Djava.awt.headless=true"
> +				     "-jar"
> +				     ,(shell-quote-argument (expand-file-name org-plantuml-jar-path))
> +                                     ,@org-plantuml-args))))

Is there a case when some arguments are suitable for dedicated binary 
but should be avoided for jar (when a user has both executable from 
system package and manually downloaded jar having newer version)? It may 
be a reason to have separate variables (or header arguments).

I suppose, a part of problem that there are no plantuml and ditaa users 
and subscribers of this list who are ready to discuss code of related 
babel packages.