OpenJDK 17 --enable-preview breaks error reporting

[nobody-famous]

I wanted to use the new switch syntax that's still a preview in 17. I changed my maven pom.xml to have

<plugin> <artifactId>maven-compiler-plugin</artifactId> <version>3.8.0</version> <configuration> <compilerArgs>--enable-preview</compilerArgs> </configuration> </plugin> In the Syntax Server output window it has,

[Error - 1:49:59 PM] Connection to server got closed. Server will not be restarted.

It stops highlighting compiler errors/warnings in the editor. Removing the --enable-preview stuff from pom.xml solves the problem, but then I lose the error reporting.

It breaks regardless of whether or not my code uses any preview features.

Environment

• Operating System: Ubuntu 20.04
• JDK version: openjdk version "17.0.3" 2022-04-19
• Visual Studio Code version: 1.69.2
• Java extension version:

Steps To Reproduce

1. [step 1]
2. [step 2]

[Please attach a sample project reproducing the error] Please attach logs

Current Result

Expected Result

Additional Informations

[fbricon]

Due to a limitation in the underlying ECJ compiler, preview fearures are only supported with the latest Java release, i.e Java 18 as of today. See https://github.com/redhat-developer/vscode-java/wiki/Enabling-Java-preview-features

One suggestion is to use a custom Maven profile that would set the Java version to 18 when running inside vscode-java or Eclipse. For instance:

<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>foo.bar</groupId>
  <artifactId>demo</artifactId>
  <version>0.0.1-SNAPSHOT</version>
 <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <java.version>17</java.version>
  </properties>
  <build>
    <plugins>
      <plugin>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.10.1</version>
        <configuration>
          <release>${java.version}</release>
          <compilerArgs>--enable-preview</compilerArgs>
        </configuration>
      </plugin>
    </plugins>
  </build>
  <profiles>
        <profile><!--Automatically activates when running inside m2e (i.e vscode-java/Eclipse)-->
            <id>m2e</id>
            <activation>
                <property>
                  <name>m2e.version</name>
                </property>
            </activation>
            <properties>
              <java.version>18</java.version>
            </properties>
        </profile>
  </profiles>
</project>

[nobody-famous]

Is there no way for it to detect that and pop up an error message instead of failing silently?