Scenario in Ditaa that "hangs" PlantUML

[Potherca]

There is a scenario when using Ditaa that causes PlantUML to "hang".

I have reduced this case to a minimum example:

@startditaa
=-
@endditaa

The online server gives: 504 Gateway Time-out The server didn't respond in time.

To reproduce locally, run:

 echo -e '@startditaa\n=-\n@endditaa' | java -jar /usr/local/share/plantuml.jar -pipe -verbose

This will give the following output:

(0.000 - 244 Mo) 237 Mo - SecurityProfile LEGACY
(0.003 - 244 Mo) 237 Mo - PlantUML Version 1.2022.5
(0.003 - 244 Mo) 237 Mo - GraphicsEnvironment.isHeadless() false
(0.004 - 244 Mo) 237 Mo - Forcing resource load on OpenJdk
(1.129 - 244 Mo) 232 Mo - Reading from string
(1.243 - 244 Mo) 228 Mo - Compilation duration 5
(1.244 - 244 Mo) 228 Mo - Regex total/invoked/compiled 0/0/0
(1.244 - 244 Mo) 228 Mo - Matches created 0

The CPU goes to 100% and the process just keeps running.
It doesn't crash but it also doesn't time-out. (I gave up after 90 minutes...)

Compared to a normal run:

$ echo -e '@startditaa\n--\n@endditaa' | java -jar /usr/local/share/plantuml.jar -pipe -verbose
(0.000 - 244 Mo) 237 Mo - SecurityProfile LEGACY
(0.002 - 244 Mo) 237 Mo - PlantUML Version 1.2022.5
(0.002 - 244 Mo) 237 Mo - GraphicsEnvironment.isHeadless() false
(0.002 - 244 Mo) 237 Mo - Forcing resource load on OpenJdk
(1.200 - 244 Mo) 231 Mo - Reading from string
(1.281 - 244 Mo) 227 Mo - Compilation duration 2
(1.282 - 244 Mo) 227 Mo - Regex total/invoked/compiled 0/0/0
(1.282 - 244 Mo) 227 Mo - Matches created 0
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IHDR<'`�}IDATx^��1
�0EA]F����4n�S��#��r�o|64��6�>������������������˜s������^�~�����������������M�FDWN'��9��IEND�B`�

I have verified that this case does work with the latest rlease of ditaa (0.11).

Running this:

 java -jar /opt/ditaa-0.11.0-standalone.jar <(echo '-=') /dev/stdout 

gives the following output:

ditaa version 0.11, Copyright (C) 2004--2017  Efstathios (Stathis) Sideris

Running with options:
Reading file: /dev/fd/63
Rendering to file: /dev/stdout
�PNG
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IHDR<'`�{IDATx^��1
�0EA�\7w��`D:�G3�.�x㳡�>v�y���DWDWDWDWDWDWDWDWDWDWDWDWDWDWDWD_���{��g^�~����������������ʏ荈��2��7x���IEND�B`�Done in 1sec

[soloturn]

as i was confused what the output of line and dotted line should be, i tried:

java -jar /tmp/ditaa-0.11.0-standalone.jar <(echo '-------================-----') /tmp/t1.png

and ditta makes it dotted:

[arnaudroques]

Thanks for the report.
This issue seems to be on Ditaa code side.
We simply don't know how to fix it :-)

So maybe you can open an issue on Ditaa (not sure that this is possible).

However, we did implement a workaround to avoid infinite loop.

This is far from perfect but at least it protects against the timeout.

Sorry we could not do better!

[Potherca]

As this usecase does work with the ditaa JAR, I asume it has something to do with the integration side of things?

@arnaudroques Do you have any details on how/where the issue lies with the Ditaa code?

So maybe you can open an issue on Ditaa (not sure that this is possible).

Ditaa is currently in a state of limbo. The original author has stated they are no longer in a position to maintain the project but a new maintainer has not (yet) been found.

[Potherca]

Closing this as the original issue is resolved by 649a13e.