Support -Werror CLI argument to treat warnings as errors

The option is named "warningsAsErrors" in the Gradle plugin

 #KT-10563 Fixed

compiler/builtins-serializer/src/org/jetbrains/kotlin/serialization/builtins/BuiltInsSerializer.kt

@@ -74,7 +74,8 @@ class BuiltInsSerializer(dependOnOldBuiltIns: Boolean) : MetadataSerializer(depe
     }
 
     private fun createMessageCollector() = object : GroupingMessageCollector(
-            PrintingMessageCollector(System.err, MessageRenderer.PLAIN_RELATIVE_PATHS, /* verbose = */ false)
+            PrintingMessageCollector(System.err, MessageRenderer.PLAIN_RELATIVE_PATHS, false),
+            false
     ) {
         override fun report(severity: CompilerMessageSeverity, message: String, location: CompilerMessageLocation?) {
             // Only report diagnostics without a particular location because there's plenty of errors in built-in sources

compiler/cli/cli-common/src/org/jetbrains/kotlin/cli/common/arguments/CommonToolArguments.kt

@@ -44,4 +44,8 @@ abstract class CommonToolArguments : Freezable(), Serializable {
     @GradleOption(DefaultValues.BooleanFalseDefault::class)
     @Argument(value = "-nowarn", description = "Generate no warnings")
     var suppressWarnings: Boolean by FreezableVar(false)
+
+    @GradleOption(DefaultValues.BooleanFalseDefault::class)
+    @Argument(value = "-Werror", description = "Report an error if there are any warnings")
+    var warningsAsErrors: Boolean by FreezableVar(false)
 }

compiler/cli/cli-common/src/org/jetbrains/kotlin/cli/common/messages/CompilerMessageSeverity.java

@@ -35,11 +35,14 @@ public enum CompilerMessageSeverity {
      */
     OUTPUT;
 
-    public static final EnumSet<CompilerMessageSeverity> ERRORS = EnumSet.of(ERROR, EXCEPTION);
     public static final EnumSet<CompilerMessageSeverity> VERBOSE = EnumSet.of(LOGGING);
 
     public boolean isError() {
-        return ERRORS.contains(this);
+        return this == EXCEPTION || this == ERROR;
+    }
+
+    public boolean isWarning() {
+        return this == STRONG_WARNING || this == WARNING;
     }
 
     @NotNull

compiler/cli/cli-common/src/org/jetbrains/kotlin/cli/common/messages/GroupingMessageCollector.java

@@ -24,16 +24,19 @@ import org.jetbrains.annotations.Nullable;
 
 import java.util.Comparator;
 import java.util.List;
+import java.util.Map;
 import java.util.Objects;
 
 public class GroupingMessageCollector implements MessageCollector {
     private final MessageCollector delegate;
+    private final boolean treatWarningsAsErrors;
 
     // Note that the key in this map can be null
     private final Multimap<CompilerMessageLocation, Message> groupedMessages = LinkedHashMultimap.create();
 
-    public GroupingMessageCollector(@NotNull MessageCollector delegate) {
+    public GroupingMessageCollector(@NotNull MessageCollector delegate, boolean treatWarningsAsErrors) {
         this.delegate = delegate;
+        this.treatWarningsAsErrors = treatWarningsAsErrors;
     }
 
     @Override
@@ -57,17 +60,29 @@ public class GroupingMessageCollector implements MessageCollector {
 
     @Override
     public boolean hasErrors() {
+        return hasExplicitErrors() || (treatWarningsAsErrors && hasWarnings());
+    }
+
+    private boolean hasExplicitErrors() {
         return groupedMessages.entries().stream().anyMatch(entry -> entry.getValue().severity.isError());
     }
 
+    private boolean hasWarnings() {
+        return groupedMessages.entries().stream().anyMatch(entry -> entry.getValue().severity.isWarning());
+    }
+
     public void flush() {
-        boolean hasErrors = hasErrors();
+        boolean hasExplicitErrors = hasExplicitErrors();
+
+        if (treatWarningsAsErrors && !hasExplicitErrors && hasWarnings()) {
+            report(CompilerMessageSeverity.ERROR, "warnings found and -Werror specified", null);
+        }
 
         List<CompilerMessageLocation> sortedKeys =
                 CollectionsKt.sortedWith(groupedMessages.keySet(), Comparator.nullsFirst(CompilerMessageLocationComparator.INSTANCE));
         for (CompilerMessageLocation location : sortedKeys) {
             for (Message message : groupedMessages.get(location)) {
-                if (!hasErrors || message.severity.isError() || message.severity == CompilerMessageSeverity.STRONG_WARNING) {
+                if (!hasExplicitErrors || message.severity.isError() || message.severity == CompilerMessageSeverity.STRONG_WARNING) {
                     delegate.report(message.severity, message.message, message.location);
                 }
             }

compiler/cli/src/org/jetbrains/kotlin/cli/common/CLICompiler.java

@@ -69,7 +69,7 @@ public abstract class CLICompiler<A extends CommonCompilerArguments> extends CLI
     @NotNull
     @Override
     public ExitCode execImpl(@NotNull MessageCollector messageCollector, @NotNull Services services, @NotNull A arguments) {
-        GroupingMessageCollector groupingCollector = new GroupingMessageCollector(messageCollector);
+        GroupingMessageCollector groupingCollector = new GroupingMessageCollector(messageCollector, arguments.getWarningsAsErrors());
 
         CompilerConfiguration configuration = new CompilerConfiguration();
         configuration.put(CLIConfigurationKeys.MESSAGE_COLLECTOR_KEY, groupingCollector);

compiler/cli/src/org/jetbrains/kotlin/cli/common/CLITool.kt

@@ -81,7 +81,7 @@ abstract class CLITool<A : CommonToolArguments> {
     fun exec(messageCollector: MessageCollector, services: Services, arguments: A): ExitCode {
         printVersionIfNeeded(messageCollector, arguments)
 
-        val fixedMessageCollector = if (arguments.suppressWarnings) {
+        val fixedMessageCollector = if (arguments.suppressWarnings && !arguments.warningsAsErrors) {
             FilteringMessageCollector(messageCollector, Predicate.isEqual(CompilerMessageSeverity.WARNING))
         }
         else {

compiler/cli/src/org/jetbrains/kotlin/cli/jvm/repl/messages/ReplTerminalDiagnosticMessageHolder.kt

@@ -28,7 +28,8 @@ class ReplTerminalDiagnosticMessageHolder : MessageCollectorBasedReporter, Diagn
     private val outputStream = ByteArrayOutputStream()
 
     override val messageCollector: GroupingMessageCollector = GroupingMessageCollector(
-            PrintingMessageCollector(PrintStream(outputStream), MessageRenderer.WITHOUT_PATHS, false)
+            PrintingMessageCollector(PrintStream(outputStream), MessageRenderer.WITHOUT_PATHS, false),
+            false
     )
 
     override val renderedDiagnostics: String

compiler/testData/cli/js-dce/dceHelp.out

@@ -8,4 +8,5 @@ where possible options include:
   -nowarn                    Generate no warnings
   -verbose                   Enable verbose logging output
   -version                   Display compiler version
+  -Werror                    Report an error if there are any warnings
 OK

compiler/testData/cli/js/jsHelp.out

@@ -25,4 +25,5 @@ where possible options include:
   -nowarn                    Generate no warnings
   -verbose                   Enable verbose logging output
   -version                   Display compiler version
+  -Werror                    Report an error if there are any warnings
 OK

compiler/testData/cli/jvm/help.out

@@ -23,4 +23,5 @@ where possible options include:
   -nowarn                    Generate no warnings
   -verbose                   Enable verbose logging output
   -version                   Display compiler version
+  -Werror                    Report an error if there are any warnings
 OK

compiler/testData/cli/jvm/werror.args

@@ -0,0 +1,4 @@
+$TESTDATA_DIR$/werror.kt
+-d
+$TEMP_DIR$
+-Werror

compiler/testData/cli/jvm/werror.kt

@@ -0,0 +1,4 @@
+fun foo(s: String, t: String?) {
+    s!!
+    t?.toString()
+}

compiler/testData/cli/jvm/werror.out

@@ -0,0 +1,5 @@
+error: warnings found and -Werror specified
+compiler/testData/cli/jvm/werror.kt:2:6: warning: unnecessary non-null assertion (!!) on a non-null receiver of type String
+    s!!
+     ^
+COMPILATION_ERROR

compiler/testData/cli/jvm/werrorWithExplicitError.args

@@ -0,0 +1,4 @@
+$TESTDATA_DIR$/werrorWithExplicitError.kt
+-d
+$TEMP_DIR$
+-Werror

compiler/testData/cli/jvm/werrorWithExplicitError.kt

@@ -0,0 +1,5 @@
+fun foo(s: String, t: String?) {
+    s!!
+    t?.toString()
+    t.length
+}

compiler/testData/cli/jvm/werrorWithExplicitError.out

@@ -0,0 +1,4 @@
+compiler/testData/cli/jvm/werrorWithExplicitError.kt:4:6: error: only safe (?.) or non-null asserted (!!.) calls are allowed on a nullable receiver of type String?
+    t.length
+     ^
+COMPILATION_ERROR

compiler/testData/cli/jvm/werrorWithNoWarn.args

@@ -0,0 +1,5 @@
+$TESTDATA_DIR$/werrorWithNoWarn.kt
+-d
+$TEMP_DIR$
+-Werror
+-nowarn

compiler/testData/cli/jvm/werrorWithNoWarn.kt

@@ -0,0 +1,4 @@
+fun foo(s: String, t: String?) {
+    s!!
+    t?.toString()
+}

compiler/testData/cli/jvm/werrorWithNoWarn.out

@@ -0,0 +1,5 @@
+error: warnings found and -Werror specified
+compiler/testData/cli/jvm/werrorWithNoWarn.kt:2:6: warning: unnecessary non-null assertion (!!) on a non-null receiver of type String
+    s!!
+     ^
+COMPILATION_ERROR

compiler/testData/cli/jvm/werrorWithStrongWarning.args

@@ -0,0 +1,6 @@
+$TESTDATA_DIR$/werrorWithStrongWarning.kt
+-d
+$TEMP_DIR$
+-Werror
+-cp
+non-existing-path.jar

compiler/testData/cli/jvm/werrorWithStrongWarning.kt

@@ -0,0 +1,4 @@
+fun foo(s: String, t: String?) {
+    s!!
+    t?.toString()
+}

compiler/testData/cli/jvm/werrorWithStrongWarning.out

@@ -0,0 +1,3 @@
+warning: classpath entry points to a non-existent location: non-existing-path.jar
+error: warnings found and -Werror specified
+COMPILATION_ERROR

compiler/tests/org/jetbrains/kotlin/cli/CliTestGenerated.java

@@ -476,6 +476,30 @@ public class CliTestGenerated extends AbstractCliTest {
             doJvmTest(fileName);
         }
 
+        @TestMetadata("werror.args")
+        public void testWerror() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/cli/jvm/werror.args");
+            doJvmTest(fileName);
+        }
+
+        @TestMetadata("werrorWithExplicitError.args")
+        public void testWerrorWithExplicitError() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/cli/jvm/werrorWithExplicitError.args");
+            doJvmTest(fileName);
+        }
+
+        @TestMetadata("werrorWithNoWarn.args")
+        public void testWerrorWithNoWarn() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/cli/jvm/werrorWithNoWarn.args");
+            doJvmTest(fileName);
+        }
+
+        @TestMetadata("werrorWithStrongWarning.args")
+        public void testWerrorWithStrongWarning() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/cli/jvm/werrorWithStrongWarning.args");
+            doJvmTest(fileName);
+        }
+
         @TestMetadata("wrongAbiVersion.args")
         public void testWrongAbiVersion() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/cli/jvm/wrongAbiVersion.args");

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/dsl/KotlinCommonOptions.kt

@@ -17,4 +17,10 @@ interface KotlinCommonOptions  : org.jetbrains.kotlin.gradle.dsl.KotlinCommonToo
      * Default value: null
      */
      var languageVersion: kotlin.String?
+
+    /**
+     * Report an error if there are any warnings
+     * Default value: false
+     */
+     var warningsAsErrors: kotlin.Boolean
 }

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/dsl/KotlinJsOptionsBase.kt

@@ -24,6 +24,11 @@ internal abstract class KotlinJsOptionsBase : org.jetbrains.kotlin.gradle.dsl.Ko
         get() = languageVersionField ?: null
         set(value) { languageVersionField = value }
 
+    private var warningsAsErrorsField: kotlin.Boolean? = null
+    override var warningsAsErrors: kotlin.Boolean
+        get() = warningsAsErrorsField ?: false
+        set(value) { warningsAsErrorsField = value }
+
     private var friendModulesDisabledField: kotlin.Boolean? = null
     override var friendModulesDisabled: kotlin.Boolean
         get() = friendModulesDisabledField ?: false
@@ -84,6 +89,7 @@ internal abstract class KotlinJsOptionsBase : org.jetbrains.kotlin.gradle.dsl.Ko
         verboseField?.let { args.verbose = it }
         apiVersionField?.let { args.apiVersion = it }
         languageVersionField?.let { args.languageVersion = it }
+        warningsAsErrorsField?.let { args.warningsAsErrors = it }
         friendModulesDisabledField?.let { args.friendModulesDisabled = it }
         mainField?.let { args.main = it }
         metaInfoField?.let { args.metaInfo = it }
@@ -103,6 +109,7 @@ internal fun org.jetbrains.kotlin.cli.common.arguments.K2JSCompilerArguments.fil
     verbose = false
     apiVersion = null
     languageVersion = null
+    warningsAsErrors = false
     friendModulesDisabled = false
     main = "call"
     metaInfo = true

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/dsl/KotlinJvmOptionsBase.kt

@@ -24,6 +24,11 @@ internal abstract class KotlinJvmOptionsBase : org.jetbrains.kotlin.gradle.dsl.K
         get() = languageVersionField ?: null
         set(value) { languageVersionField = value }
 
+    private var warningsAsErrorsField: kotlin.Boolean? = null
+    override var warningsAsErrors: kotlin.Boolean
+        get() = warningsAsErrorsField ?: false
+        set(value) { warningsAsErrorsField = value }
+
     private var includeRuntimeField: kotlin.Boolean? = null
     override var includeRuntime: kotlin.Boolean
         get() = includeRuntimeField ?: false
@@ -64,6 +69,7 @@ internal abstract class KotlinJvmOptionsBase : org.jetbrains.kotlin.gradle.dsl.K
         verboseField?.let { args.verbose = it }
         apiVersionField?.let { args.apiVersion = it }
         languageVersionField?.let { args.languageVersion = it }
+        warningsAsErrorsField?.let { args.warningsAsErrors = it }
         includeRuntimeField?.let { args.includeRuntime = it }
         javaParametersField?.let { args.javaParameters = it }
         jdkHomeField?.let { args.jdkHome = it }
@@ -79,6 +85,7 @@ internal fun org.jetbrains.kotlin.cli.common.arguments.K2JVMCompilerArguments.fi
     verbose = false
     apiVersion = null
     languageVersion = null
+    warningsAsErrors = false
     includeRuntime = false
     javaParameters = false
     jdkHome = null