I am using Forge v10.13.2.1230 for Minecraft v1.7.10."gradlew build" works for the example mod that ships with Forge src, but fails for my mod. I've tried running it with JAVA_HOME set to JDK v1.6 and JDK v1.7 with identical results. Following is gradle log:

 

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Searge, ProfMobius, Fesh0r, 
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:compileApiJava UP-TO-DATE
:processApiResources UP-TO-DATE
:apiClasses UP-TO-DATE
:sourceMainJava UP-TO-DATE
:compileJava UP-TO-DATE
:processResources UP-TO-DATE
:classes UP-TO-DATE
:jar UP-TO-DATE
:compileTestJava UP-TO-DATE
:processTestResources UP-TO-DATE
:testClasses UP-TO-DATE
:test UP-TO-DATE
:extractMcpData UP-TO-DATE
:getVersionJson
:extractUserDev UP-TO-DATE
:genSrgs SKIPPED
:reobf FAILED

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':reobf'.
> java.lang.IllegalArgumentException (no error message)

* Try:
Run with --info or --debug option to get more log output.

* Exception is:
org.gradle.api.tasks.TaskExecutionException: Execution failed for task ':reobf'.
at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:69)
at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:46)
at org.gradle.api.internal.tasks.execution.PostExecutionAnalysisTaskExecuter.execute(PostExecutionAnalysisTaskExecuter.java:35)
at org.gradle.api.internal.tasks.execution.SkipUpToDateTaskExecuter.execute(SkipUpToDateTaskExecuter.java:64)
at org.gradle.api.internal.tasks.execution.ValidatingTaskExecuter.execute(ValidatingTaskExecuter.java:58)
at org.gradle.api.internal.tasks.execution.SkipEmptySourceFilesTaskExecuter.execute(SkipEmptySourceFilesTaskExecuter.java:42)
at org.gradle.api.internal.tasks.execution.SkipTaskWithNoActionsExecuter.execute(SkipTaskWithNoActionsExecuter.java:52)
at org.gradle.api.internal.tasks.execution.SkipOnlyIfTaskExecuter.execute(SkipOnlyIfTaskExecuter.java:53)
at org.gradle.api.internal.tasks.execution.ExecuteAtMostOnceTaskExecuter.execute(ExecuteAtMostOnceTaskExecuter.java:43)
at org.gradle.api.internal.AbstractTask.executeWithoutThrowingTaskFailure(AbstractTask.java:289)
at org.gradle.execution.taskgraph.AbstractTaskPlanExecutor$TaskExecutorWorker.executeTask(AbstractTaskPlanExecutor.java:79)
at org.gradle.execution.taskgraph.AbstractTaskPlanExecutor$TaskExecutorWorker.processTask(AbstractTaskPlanExecutor.java:63)
at org.gradle.execution.taskgraph.AbstractTaskPlanExecutor$TaskExecutorWorker.run(AbstractTaskPlanExecutor.java:51)
at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$1.run(DefaultTaskPlanExecutor.java:33)
at org.gradle.internal.Factories$1.create(Factories.java:22)
at org.gradle.cache.internal.DefaultCacheAccess.longRunningOperation(DefaultCacheAccess.java:198)
at org.gradle.cache.internal.DefaultCacheAccess.longRunningOperation(DefaultCacheAccess.java:266)
at org.gradle.cache.internal.DefaultPersistentDirectoryStore.longRunningOperation(DefaultPersistentDirectoryStore.java:135)
at org.gradle.api.internal.changedetection.state.DefaultTaskArtifactStateCacheAccess.longRunningOperation(DefaultTaskArtifactStateCacheAccess.java:95)
at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor.process(DefaultTaskPlanExecutor.java:31)
at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter.execute(DefaultTaskGraphExecuter.java:86)
at org.gradle.execution.SelectedTaskExecutionAction.execute(SelectedTaskExecutionAction.java:29)
at org.gradle.execution.DefaultBuildExecuter.execute(DefaultBuildExecuter.java:61)
at org.gradle.execution.DefaultBuildExecuter.access$200(DefaultBuildExecuter.java:23)
at org.gradle.execution.DefaultBuildExecuter$2.proceed(DefaultBuildExecuter.java:67)
at org.gradle.execution.DryRunBuildExecutionAction.execute(DryRunBuildExecutionAction.java:32)
at org.gradle.execution.DefaultBuildExecuter.execute(DefaultBuildExecuter.java:61)
at org.gradle.execution.DefaultBuildExecuter.execute(DefaultBuildExecuter.java:54)
at org.gradle.initialization.DefaultGradleLauncher.doBuildStages(DefaultGradleLauncher.java:166)
at org.gradle.initialization.DefaultGradleLauncher.doBuild(DefaultGradleLauncher.java:113)
at org.gradle.initialization.DefaultGradleLauncher.run(DefaultGradleLauncher.java:81)
at org.gradle.launcher.exec.InProcessBuildActionExecuter$DefaultBuildController.run(InProcessBuildActionExecuter.java:64)
at org.gradle.launcher.cli.ExecuteBuildAction.run(ExecuteBuildAction.java:33)
at org.gradle.launcher.cli.ExecuteBuildAction.run(ExecuteBuildAction.java:24)
at org.gradle.launcher.exec.InProcessBuildActionExecuter.execute(InProcessBuildActionExecuter.java:35)
at org.gradle.launcher.exec.InProcessBuildActionExecuter.execute(InProcessBuildActionExecuter.java:26)
at org.gradle.launcher.cli.RunBuildAction.run(RunBuildAction.java:50)
at org.gradle.internal.Actions$RunnableActionAdapter.execute(Actions.java:171)
at org.gradle.launcher.cli.CommandLineActionFactory$ParseAndBuildAction.execute(CommandLineActionFactory.java:201)
at org.gradle.launcher.cli.CommandLineActionFactory$ParseAndBuildAction.execute(CommandLineActionFactory.java:174)
at org.gradle.launcher.cli.CommandLineActionFactory$WithLogging.execute(CommandLineActionFactory.java:170)
at org.gradle.launcher.cli.CommandLineActionFactory$WithLogging.execute(CommandLineActionFactory.java:139)
at org.gradle.launcher.cli.ExceptionReportingAction.execute(ExceptionReportingAction.java:33)
at org.gradle.launcher.cli.ExceptionReportingAction.execute(ExceptionReportingAction.java:22)
at org.gradle.launcher.Main.doAction(Main.java:46)
at org.gradle.launcher.bootstrap.EntryPoint.run(EntryPoint.java:45)
at org.gradle.launcher.Main.main(Main.java:37)
at org.gradle.launcher.bootstrap.ProcessBootstrap.runNoExit(ProcessBootstrap.java:50)
at org.gradle.launcher.bootstrap.ProcessBootstrap.run(ProcessBootstrap.java:32)
at org.gradle.launcher.GradleMain.main(GradleMain.java:23)
at org.gradle.wrapper.BootstrapMainStarter.start(BootstrapMainStarter.java:30)
at org.gradle.wrapper.WrapperExecutor.execute(WrapperExecutor.java:127)
at org.gradle.wrapper.GradleWrapperMain.main(GradleWrapperMain.java:58)
Caused by: java.lang.IllegalArgumentException
at org.objectweb.asm.MethodVisitor.<init>(MethodVisitor.java:86)
at org.objectweb.asm.MethodVisitor.<init>(MethodVisitor.java:71)
at net.minecraftforge.gradle.extrastuff.ReobfExceptor$JarInfo$1.<init>(ReobfExceptor.java:374)
at net.minecraftforge.gradle.extrastuff.ReobfExceptor$JarInfo.visitMethod(ReobfExceptor.java:373)
at org.objectweb.asm.ClassReader.readMethod(ClassReader.java:852)
at org.objectweb.asm.ClassReader.accept(ClassReader.java:669)
at org.objectweb.asm.ClassReader.accept(ClassReader.java:506)
at net.minecraftforge.gradle.extrastuff.ReobfExceptor.readJar(ReobfExceptor.java:154)
at net.minecraftforge.gradle.extrastuff.ReobfExceptor.doFirstThings(ReobfExceptor.java:80)
at net.minecraftforge.gradle.tasks.user.reobf.ReobfTask.getExceptor(ReobfTask.java:319)
at net.minecraftforge.gradle.tasks.user.reobf.ReobfTask.doTask(ReobfTask.java:277)
at org.gradle.internal.reflect.JavaMethod.invoke(JavaMethod.java:63)
at org.gradle.api.internal.project.taskfactory.AnnotationProcessingTaskFactory$StandardTaskAction.doExecute(AnnotationProcessingTaskFactory.java:219)
at org.gradle.api.internal.project.taskfactory.AnnotationProcessingTaskFactory$StandardTaskAction.execute(AnnotationProcessingTaskFactory.java:212)
at org.gradle.api.internal.project.taskfactory.AnnotationProcessingTaskFactory$StandardTaskAction.execute(AnnotationProcessingTaskFactory.java:201)
at org.gradle.api.internal.AbstractTask$TaskActionWrapper.execute(AbstractTask.java:533)
at org.gradle.api.internal.AbstractTask$TaskActionWrapper.execute(AbstractTask.java:516)
at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeAction(ExecuteActionsTaskExecuter.java:80)
at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:61)
... 52 more


BUILD FAILED

Total time: 8.791 secs

 

The stack trace seems to point to the following line in org.objectweb.asm.MethodVisitor (although the line number doesn't match the log - does gradle use a different ASM jar from the one that's in the mod's build path?)

if (api != Opcodes.ASM4 && api != Opcodes.ASM5) {
     throw new IllegalArgumentException();
}

It worked after I changed "runDir" in build.gradle from "run/assets" or "eclipse/assets" (which I had from an older version of Forgem when that variable was called "assetDir") to just "run" or "eclipse". I still have no idea what that folder has to do with building, because it remained empty. An explanation will be appreciated.

 

EDIT: Never mind, it worked once, now it doesn't work again. Please help.

I tried this:

gradlew cleanCache
gradlew setupDevWorkspace
gradlew eclipse

And the build worked. But after I added

gradlew setupDecompWorkspace

the error appeared again.

Once again, it worked 1 time, then on subsequent launches of "gradlew build" it failed on task ":reobf" with the same exception.

Before that I had been working as usual: added some texture assets, modified some code, nothing that should have changed the way the project is built. I did restart my computer once, so I suppose, that could possibly be the reason why it did work once again.

I had the same problem with 1.7.10. CleanCache fixed the issue. But then I updated to 1.8 and the issue was back. I tried cleanCache several times, but no luck. I hope someone here knows what went wrong, as I'm not able to build any mod for 1.8 right now.

 

EDIT: Okay, I managed to get it built by running cleanCache command and then build command (no SetupDecompWorkspace in between). I wish there was better solution, though.

So I ran cleanCache again and it worked, then after some time and setupDecompWorkspace it started failing again. I ran cleanCache once again, and setupDecompWorkspace too, because I need it for development, and after that it has worked several times so far.

 

EDIT: later today, it broke again

I also had this issue. My first fix was using the "--refresh-dependencies" gradle arg. Worked every time but really slowed down build time as it has to redownload the deps each time.

 

Today I tried totally re-installing forge gradle by just deleting the .gradle folder in my user area (beware downloads take ages). This seems to have fixed the issue but I've only run 5 test builds so far.