Antora plantuml diagrams rendering not working

[austek]

When using antora, plantuml diagrams are not rendering, however, are generated correctly on the generated site.

Here is a repo that reproduces the issue
https://github.com/austek/antora-diagram

Standard asciidoc file preview works docs/asciidoc/index.adoc

Open docs/modules/ROOT/pages/index.adoc, following error is shown
Failed to generate image: undefined method to_sym' for nil:NilClass (index.adoc, line 6) (script:process)`

Environment

Plugin Version: 0.37.56

IntelliJ Details:
IntelliJ IDEA 2022.2.4 (Ultimate Edition)
Build #IU-222.4459.24, built on November 22, 2022
Runtime version: 17.0.5+7-b469.71 x86_64
VM: OpenJDK 64-Bit Server VM by JetBrains s.r.o.
macOS 12.6.1
GC: G1 Young Generation, G1 Old Generation
Memory: 6144M
Cores: 12
Metal Rendering is ON
Registry:
ide.images.show.chessboard=true

Non-Bundled Plugins:
org.rust.lang (0.4.184.5057-222)
name.kropp.intellij.makefile (222.4459.16)
palantir-java-format (2.28.0)
org.jetbrains.plugins.hocon (2022.1.0)
org.jetbrains.kotlin (222-1.7.21-release-272-IJ4167.29)
com.intellij.guice (222.4459.16)
com.euphoricity.gitignore (0.3)
com.dmarcotte.handlebars (222.4459.16)
com.intellij.lang.jsgraphql (3.3.0)
String Manipulation (9.6.1)
org.sonarlint.idea (7.2.1.58118)
com.rspn.git (1.9)
org.jetbrains.plugins.ruby (222.4459.16)
org.asciidoctor.intellij.asciidoc (0.37.56)
com.crunch42.openapi (1.41)
EclipseCodeFormatter (22.0.203.000.0-Eclipse_2021-09)
CheckStyle-IDEA (5.74.0)
spring-javaformat (0.0.34)
ru.adelf.idea.dotenv (2022.2)
com.haulmont.jpab (2022.5.0-222)
com.zxy.idea.plugin.gradle-plugin-support (1.1)

Kotlin: 222-1.7.21-release-272-IJ4167.29

[ahus1]

I'm sorry to hear this is not working for your diagrams. I can reproduce it locally when using Asciidoctor Diagram in IntelliJ. I can't offer a solution for this yet. In the meantime, I suggest that you enable Kroki in the plugin's settings, as this will generate the diagram as expected.

[Smasherr]

I have a slightly different error message (MacOS, IntelliJ 2023.3.2, Asciidoctor-plugin 0.41.6), and I am also able to fix it by enabling Kroki.