compileMain24Java fails with JDK25+

[dweiss]

Update: JDK bug - https://bugs.openjdk.org/browse/JDK-8359596

Policeman jenkins complains when compiling against new Java versions, for example:

./gradlew compileMain24Java -Pruntime.java.home=/jdks/jdk-25+27 --rerun-tasks

the problem is this:

warning: [options] location of system modules is not set in conjunction with -source 24
  not setting the location of system modules may lead to class files that cannot run on JDK 24
    --release 24 is recommended instead of -source 24 -target 24 because it sets the location of system modules automatically
error: warnings found and -Werror specified

but we do set:

-Xlint:-options

so I'm not sure why this warning is even triggered. We also can't use --release because we do some other tweaks to java.base in lucene.java.core.mrjar.gradle.

I added a temporary hack to not use -Werror on runtime java jdk25+.

[dweiss]

This used to work with JDK 25-beta+11-ea.

[uschindler]

I opened an issue @ JDK: https://bugs.openjdk.org/browse/JDK-8359596

This used to work with JDK 25-beta+11-ea.

It also worked afterwards (25 ea+15). It is a rather new problem.

[uschindler]

I added a similar hack to 10.x branch: 2503e83

I'd prefer to only apply this to the MR-JAR part of compilation:

 build-tools/build-infra/src/main/groovy/lucene.java.core.mrjar.gradle | 2 ++
 build-tools/build-infra/src/main/groovy/lucene.java.javac.gradle      | 2 +-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/build-tools/build-infra/src/main/groovy/lucene.java.core.mrjar.gradle b/build-tools/build-infra/src/main/groovy/lucene.java.core.mrjar.gradle
index 60a4588ba2d..3838cf9854f 100644
--- a/build-tools/build-infra/src/main/groovy/lucene.java.core.mrjar.gradle
+++ b/build-tools/build-infra/src/main/groovy/lucene.java.core.mrjar.gradle
@@ -43,6 +43,8 @@ configure(project(":lucene:core")) {
           "--add-exports",
           "java.base/jdk.incubator.vector=ALL-UNNAMED",
         ]
+        // hack because -Xlint:-options does not work for all options (regression in JDK 25+?):
+        options.compilerArgs.remove("-Werror")
 
         def argsProvider = objects.newInstance(CompilerArgsProvider)
         argsProvider.apiJarFile.set(apijar)
diff --git a/build-tools/build-infra/src/main/groovy/lucene.java.javac.gradle b/build-tools/build-infra/src/main/groovy/lucene.java.javac.gradle
index 67aaf29c7a4..8f20d9c030b 100644
--- a/build-tools/build-infra/src/main/groovy/lucene.java.javac.gradle
+++ b/build-tools/build-infra/src/main/groovy/lucene.java.javac.gradle
@@ -81,7 +81,7 @@ tasks.withType(JavaCompile).configureEach {
     // proc:none was added because of LOG4J2-1925 / JDK-8186647
     options.compilerArgs += ["-proc:none"]
 
-    if (failOnWarningsOption.get() && (rootProject.ext.runtimeJavaVersion < JavaVersion.VERSION_25)) {
+    if (failOnWarningsOption.get()) {
       options.compilerArgs += "-Werror"
     }
   }

[uschindler]

Of course you could add the version check, too, but disabling -Werror for the MR-JAR part is fine IMHO, because it is a hack anyways and further warnings may appear any time soon.

[dweiss]

I've applied your patch, looks better indeed, thank you.

[dweiss]

I looked at the JDK issue and Archie couldn't reproduce the issue. Here's a repro -

.../jdk-25+27/bin/javac -source 24 -target 24 -Xlint:options -Xlint:-options -Werror Foo.java
warning: [options] location of system modules is not set in conjunction with -source 24
  not setting the location of system modules may lead to class files that cannot run on JDK 24
    --release 24 is recommended instead of -source 24 -target 24 because it sets the location of system modules automatically
error: warnings found and -Werror specified
1 error
1 warning

note there is a pair of -Xlint options - one enabling, the other disabling the 'options' flag. Archie is right that it works well if it's just -Xlint:-options so I don't know if it should be classified as a bug in JDK... perhaps it could be more informative about conflicting options (or use their sequential order to enable/disable flags).

I'll try to fix it in our build.

[uschindler]

I updated the JDK bug report.