Fix javac task inputs so that they include modular dependencies #12742 (#12745)

Fix javac task inputs so that they include modular dependencies #12742

Author: dweiss

gradle/java/modules.gradle

@@ -67,6 +67,12 @@ allprojects {
       tasks.named(sourceSet.getCompileJavaTaskName()).configure({ JavaCompile task ->
         task.dependsOn modularPaths.compileModulePathConfiguration
 
+        // GH-12742: add the modular path as inputs so that if anything changes, the task
+        // is not up to date and is re-run. I [dw] believe this should be a @Classpath parameter
+        // on the task itself... but I don't know how to implement this on an existing class.
+        // this is a workaround but should work just fine though.
+        task.inputs.files(modularPaths.compileModulePathConfiguration)
+
         // LUCENE-10327: don't allow gradle to emit an empty sourcepath as it would break
         // compilation of modules.
         task.options.setSourcepath(sourceSet.java.sourceDirectories)

lucene/CHANGES.txt

@@ -278,7 +278,11 @@ Bug Fixes
 Build
 ---------------------
 
+* GITHUB#12742: JavaCompile tasks may be in up-to-date state when modular dependencies have changed 
+  leading to odd runtime errors (Chris Hostetter, Dawid Weiss)
+
 * GITHUB#12612: Upgrade forbiddenapis to version 3.6 and ASM for APIJAR extraction to 9.6.  (Uwe Schindler)
+
 * GITHUB#12655: Upgrade to Gradle 8.4 (Kevin Risden)
 
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