Escaped HTML characters in flexmark output

[evanbergstrom]

I'm having a problem with the HTML output of flexmark-java being further processed and escaping characters in the HTML tags. I created a simple example class that shows the problem:

/**
 * This class is an example for using markdown in java doc.
 * ```java
 *  public void foo(bar b) {}
 * ```
 */
public class MDocletExample {
}

The block of HTML generated by javadoc for the comment is:

<div class="block">This class is an example for using markdown in java doc.&lt;pre&gt;&lt;code class="language-java"&gt;  public void foo(bar b) {}
&lt;/code&gt;&lt;/pre&gt;
</div>

It looks like something is taking the output of flexmark and escaping the < and > characters in the HTML. I'm using maven as the build tool. Here is the pom.xml for the example:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.example</groupId>
  <artifactId>mdoclet-example</artifactId>
  <version>0.1</version>
  <packaging>jar</packaging>

  <build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.11.0</version>
            <configuration>
              <source>17</source>
              <target>17</target>
              <debug>true</debug>
            </configuration>
          </plugin>
          <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-javadoc-plugin</artifactId>
            <version>3.4.1</version>
            <configuration>
              <doclet>org.jdrupes.mdoclet.MDoclet</doclet>
              <docletArtifacts>
                <docletArtifact>
                  <groupId>org.jdrupes.mdoclet</groupId>
                  <artifactId>doclet</artifactId>
                  <version>3.1.0</version>
                </docletArtifact>
                <docletArtifact>
                  <groupId>com.vladsch.flexmark</groupId>
                  <artifactId>flexmark-all</artifactId>
                  <version>0.64.8</version>
                </docletArtifact>
              </docletArtifacts>
              <additionalJOptions>
                <additionalJOption>-J--add-exports=jdk.javadoc/jdk.javadoc.internal.tool=ALL-UNNAMED</additionalJOption>
                <additionalJOption>-J--add-exports=jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED</additionalJOption>
              </additionalJOptions>
            </configuration>
        </plugin>
    </plugins>
  </build>
</project>

[mnlipp]

Sorry, but I cannot reproduce this. I've added your source in mdoclet/testfiles/test and run the test with JRE 17 and my "default test setup"

The result is (as to be expected):

Maybe something's wrong with your maven configuration, but as I don't know anything about maven, I cannot help you with that. Maybe compare the java invocation that all this maven magic results in.

Feel free to reopen this issue when you have any additional information.

[evanbergstrom]

I found the issue. The maven compiler plugin was running on JDK 17, the javadoc plugin was running on OpenJDK 20. Maybe there is a compatibility issue with the JDK 20 javadoc?

For anyone else having this problem, setting your JAVA_HOME to the same executable as the compiler plugin is using will fix it. I don't like having to mess around with environment variables, so I went with the approach of using the maven-toolchain-plugin, and that synchronized the version across all of the plugins while still making it easy to switch the versions around.

[mnlipp]

I found the issue. The maven compiler plugin was running on JDK 17, the javadoc plugin was running on OpenJDK 20. Maybe there is a compatibility issue with the JDK 20 javadoc?

This wouldn't surprise me. Remember that I'm using a private API here and "hack my way around" (and the original authors have done many things to make this as difficult as possible, violating most rules of best practice OO design). I'll have a look at this again when the next LTS release comes out. Until then everybody should be aware that the doclet is supposed to be run with Java 17 -- anything else is pure luck.