Make ERRORPRONE warnings into errors by changing javacopts

tools/build_rules/java.bzl

@@ -0,0 +1,71 @@
+# Enable some Error Prone checks that are not on by default.  Then, enable warnings:
+# Bazel as of 0.5.1 doesn't enable the default warnings for Error Prone (see
+# https://github.com/bazelbuild/bazel/issues/2237), so we enable them individually here.
+JAVACOPTS = [
+		'-XepDisableWarningsInGeneratedCode',
+		'-Xep:MissingCasesInEnumSwitch:ERROR',
+		'-Xep:ReferenceEquality:ERROR',
+		'-Xep:StringEquality:ERROR',
+		'-Xep:WildcardImport:ERROR',
+		'-Xep:AmbiguousMethodReference:WARN',
+		'-Xep:BadAnnotationImplementation:WARN',
+		'-Xep:BadComparable:WARN',
+		'-Xep:BoxedPrimitiveConstructor:ERROR',
+		'-Xep:CannotMockFinalClass:WARN',
+		'-Xep:ClassCanBeStatic:WARN',
+		'-Xep:ClassNewInstance:WARN',
+		'-Xep:DefaultCharset:WARN',
+		'-Xep:DoubleCheckedLocking:WARN',
+		'-Xep:ElementsCountedInLoop:WARN',
+		'-Xep:EqualsHashCode:WARN',
+		'-Xep:EqualsIncompatibleType:WARN',
+		'-Xep:Finally:WARN',
+		'-Xep:FloatingPointLiteralPrecision:WARN',
+		'-Xep:FragmentInjection:WARN',
+		'-Xep:FragmentNotInstantiable:WARN',
+		'-Xep:FunctionalInterfaceClash:WARN',
+		'-Xep:FutureReturnValueIgnored:WARN',
+		'-Xep:GetClassOnEnum:WARN',
+		'-Xep:ImmutableAnnotationChecker:WARN',
+		'-Xep:ImmutableEnumChecker:WARN',
+		'-Xep:IncompatibleModifiers:WARN',
+		'-Xep:InjectOnConstructorOfAbstractClass:WARN',
+		'-Xep:InputStreamSlowMultibyteRead:WARN',
+		'-Xep:IterableAndIterator:WARN',
+		'-Xep:JUnit3FloatingPointComparisonWithoutDelta:WARN',
+		'-Xep:JUnitAmbiguousTestClass:WARN',
+		'-Xep:LiteralClassName:WARN',
+		'-Xep:MissingFail:WARN',
+		'-Xep:MissingOverride:WARN',
+		'-Xep:MutableConstantField:WARN',
+		'-Xep:NarrowingCompoundAssignment:WARN',
+		'-Xep:NonAtomicVolatileUpdate:WARN',
+		'-Xep:NonOverridingEquals:WARN',
+		'-Xep:NullableConstructor:WARN',
+		'-Xep:NullablePrimitive:WARN',
+		'-Xep:NullableVoid:WARN',
+		'-Xep:OperatorPrecedence:WARN',
+		'-Xep:OverridesGuiceInjectableMethod:WARN',
+		'-Xep:PreconditionsInvalidPlaceholder:WARN',
+		'-Xep:ProtoFieldPreconditionsCheckNotNull:WARN',
+		'-Xep:ProtocolBufferOrdinal:WARN',
+		'-Xep:RequiredModifiers:WARN',
+		'-Xep:ShortCircuitBoolean:WARN',
+		'-Xep:SimpleDateFormatConstant:WARN',
+		'-Xep:StaticGuardedByInstance:WARN',
+		'-Xep:SynchronizeOnNonFinalField:WARN',
+		'-Xep:TruthConstantAsserts:WARN',
+		'-Xep:TypeParameterShadowing:WARN',
+		'-Xep:TypeParameterUnusedInFormals:WARN',
+		'-Xep:URLEqualsHashCode:WARN',
+		'-Xep:UnsynchronizedOverridesSynchronized:WARN',
+		'-Xep:WaitNotInLoop:WARN',
+]
+
+def java_library(javacopts=[], **kwargs):
+	if native.repository_name() == '@':
+		# When building any java target in our repository (i.e. not ones that are loaded into the WORKSPACE with
+		# http_archive and friends), apply our javac options.  We don't apply them to external code because that code
+		# may not adhere to our rules.
+		javacopts += JAVACOPTS
+	native.java_library(javacopts=javacopts, **kwargs)])]

tools/build_rules/prelude_bazel

@@ -0,0 +1,2 @@
+load("@//tools/build_rules:java.bzl", "java_library")
+