PlantUML @start<engine> not recognized

[tllngr]

Describe the bug
When using special commands @start<engine> and @end<engine>, doxygen outputs warning unknown command instead of using plantuml to render desired content.

Expected behavior
Expect usage of @start<engine> and @end<engine> works as described in manual at https://www.doxygen.nl/manual/commands.html#cmdstartuml

To Reproduce
Use project from attached .zip doxygen_plantuml_issue.zip

Included markdown file main.md contains:

# Main

@startjson
{
"fruit": "Apple",
"size": "Large"
}
@endjson

@startuml
A --> B
@enduml

• Running doxygen to generate html only output will cause error messages:

$ doxygen
...
mytest/main.md:3: warning: Found unknown command '@startjson'
mytest/main.md:8: warning: Found unknown command '@endjson'
...

As result, generated html page html/md_main.html shows unrendered plain text of the start/endjson block. The second block start/enduml is rendered. Tried also salt, yaml and others. Looks like everything other than start/enduml is not recognized.

Example project is attached to this issue

Version

• Doxygen version: 1.9.5 (2f6875a), built from source
• Plantuml plantuml-1.2022.7.jar (downloaded from https://github.com/plantuml/plantuml/releases/download/v1.2022.7/plantuml-1.2022.7.jar), installed at /usr/local/share/plantuml/plantuml-1.2022.7.jar
• Platform: Linux x64

  Distributor ID: Linuxmint
  Description: Linux Mint 20.3
  Release: 20.3
  Codename: una

Attachement
doxygen_plantuml_issue.zip

[albert-github]

Doxygen does not support the individual start commands for plantuml like @startjson but it supports @startuml{json}, the user can define an own command in the ALIASES settings like ALIASES += startjson=@startuml{json} and ALIASES += endjson=@enduml.

The chosen strategy is a design decision.

[tllngr]

Hi Albert,

It works like you described it. I'd suggest to fix documentation at https://www.doxygen.nl/manual/commands.html#cmdstartuml by putting in your description and maybe extend/modify the example

Thank you for your quick reply and help!

[albert-github]

Regarding the documentation suggestion I've just pushed a proposed patch, pull request #9606

[albert-github]

Code has been integrated in master on GitHub (please don't close the issue as this will be done at the moment of an official release).

[tllngr]

Hi Albert!

Thanks for adding it to the docs

[doxygen]

This issue was previously marked 'fixed but not released',
which means it should be fixed in doxygen version 1.9.6.
Please verify if this is indeed the case. Reopen the
issue if you think it is not fixed and please include any additional information
that you think can be relevant (preferably in the form of a self-contained example).

[MrNice2001]

ALIASES += startjson=@startuml{json} and ALIASES += endjson=@enduml

I tried to verify the proposed solution but the diagram of the JSON data (from main.md) is not present.

Procedure

1. Extracted doxygen_plantuml_issue.zip
2. Added to Doxyfile

                ALIASES               += startjson=@startuml{json}
                ALIASES               += endjson=@enduml           

3. Updated PLANTUML_JAR_PATH in Doxyfile
4. Executed doxygen Doxyfile with Doxygen v1.9.6

Result
No errors nor warnings during Doxygen execution, good.

Issue
But the first diagram is not generated, the JSON data is not displayed in a diagram.

My Understanding
The aliases are applied. Therefore, the main.md will be in interpreted in the following way:

# Main

@startuml{json}
{
"fruit": "Apple",
"test": "Apple"
}
@enduml

@startuml
A --> B
@enduml

The JSON data cannot be handled by PlantUML within the section @startuml and @enduml. Is my understanding correct? If yes, may we reopen this issue?

[tllngr]

@MrNice2001

Your procedure works on my linux x86_64 machine using doxygen 1.9.6 and plantuml-1.2023.4.jar.
The json part shows up as diagram as expected

You may try the following:

• Use a new shell terminal instance and ensure doxygen --version does output version number 1.9.6
• Delete doxygen output dir htmlbefore running doxygen

[albert-github]

@MrNice2001 as indicated by @tllngr this should work.

what does the following command line command return:

java -Djava.awt.headless=true -jar /usr/local/share/plantuml/plantuml-1.2022.7.jar -version

what does the following command return in your case:

doxygen -q -d markdown -d extcmd Doxyfile

[MrNice2001]

@MrNice2001

Your procedure works on my linux x86_64 machine using doxygen 1.9.6 and plantuml-1.2023.4.jar. The json part shows up as diagram as expected

You may try the following:

* Use a new shell terminal instance and ensure `doxygen --version` does output version number `1.9.6`

* Delete doxygen output dir `html`before running doxygen

I updated to plantuml-1.2023.4.jar and now it works for me as well.

Here is my takeaway:

• PlantUML
  Version 1.2020.2 is not sufficent
  Version 1.2023.4 is sufficent
• Configuration is needed:

	ALIASES               += startjson=@startuml{json}
	ALIASES               += endjson=@enduml  

• Doxygen
  Version 1.9.1 is not sufficent
  Version 1.9.6 is sufficent

Thanks you for your swift support!!!

[MrNice2001]

@MrNice2001 as indicated by @tllngr this should work.

what does the following command line command return:

java -Djava.awt.headless=true -jar /usr/local/share/plantuml/plantuml-1.2022.7.jar -version

what does the following command return in your case:

doxygen -q -d markdown -d extcmd Doxyfile

Here the output:

java -Djava.awt.headless=true -jar /usr/share/plantuml/plantuml.jar -version

PlantUML version 1.2020.02 (Sun Mar 01 11:22:07 CET 2020)
(GPL source distribution)
Java Runtime: OpenJDK Runtime Environment
JVM: OpenJDK 64-Bit Server VM
Java Version: 17.0.6+10-Ubuntu-0ubuntu122.04
Operating System: Linux
Default Encoding: UTF-8
Language: en
Country: US
Machine: d-ryzen
PLANTUML_LIMIT_SIZE: 4096
Processors: 12
Max Memory: 16,844,324,864
Total Memory: 1,073,741,824
Free Memory: 1,058,011,120
Used Memory: 15,730,704
Thread Active Count: 1

The environment variable GRAPHVIZ_DOT has not been set
Dot executable is /usr/bin/dot
Dot version: dot - graphviz version 2.43.0 (0)
Installation seems OK. File generation OK

An update to PlantUML Version 1.2023.4 solved my issue.

For the sake of completeness, here the second output

doxygen-1.9.6/bin/doxygen -q -d markdown -d extcmd Doxyfile

======== Markdown =========
---- input ------- 
# Main

@startuml{json}
{
"fruit": "Apple",
"test": "Apple"
}
@enduml


@startuml
A --> B
@enduml



---- output -----
@page md_main Main\ilinebr 

@startuml{json}
{
"fruit": "Apple",
"test": "Apple"
}
@enduml


@startuml
A --> B
@enduml



=========

Thank you for your swift support!!!