Report warning for non-boolean CLI argument passed multiple times

Only if its values are different, see the test

compiler/cli/cli-common/src/org/jetbrains/kotlin/cli/common/arguments/CommonCompilerArguments.java

@@ -20,7 +20,9 @@ import com.intellij.util.SmartList;
 import org.jetbrains.annotations.NotNull;
 
 import java.io.Serializable;
+import java.util.LinkedHashMap;
 import java.util.List;
+import java.util.Map;
 
 public abstract class CommonCompilerArguments implements Serializable {
     public static final long serialVersionUID = 0L;
@@ -105,6 +107,10 @@ public abstract class CommonCompilerArguments implements Serializable {
     // Names of extra (-X...) arguments which have been passed in an obsolete form ("-Xaaa bbb", instead of "-Xaaa=bbb")
     public List<String> extraArgumentsPassedInObsoleteForm = new SmartList<>();
 
+    // Non-boolean arguments which have been passed multiple times, possibly with different values.
+    // The key in the map is the name of the argument, the value is the last passed value.
+    public Map<String, String> duplicateArguments = new LinkedHashMap<>();
+
     @NotNull
     public static CommonCompilerArguments createDefaultInstance() {
         return new DummyImpl();

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

@@ -30,6 +30,7 @@ val Argument.isAdvanced: Boolean
 
 private val ADVANCED_ARGUMENT_PREFIX = "-X"
 
+// Parses arguments in the passed [result] object, or throws an [IllegalArgumentException] with the message to be displayed to the user
 fun <A : CommonCompilerArguments> parseCommandLineArguments(args: Array<String>, result: A) {
     data class ArgumentField(val field: Field, val argument: Argument)
 
@@ -38,6 +39,8 @@ fun <A : CommonCompilerArguments> parseCommandLineArguments(args: Array<String>,
         if (argument != null) ArgumentField(field, argument) else null
     }
 
+    val visitedArgs = mutableSetOf<String>()
+
     var i = 0
     while (i < args.size) {
         val arg = args[i++]
@@ -74,6 +77,10 @@ fun <A : CommonCompilerArguments> parseCommandLineArguments(args: Array<String>,
             }
         }
 
+        if (!field.type.isArray && !visitedArgs.add(argument.value) && value is String && field.get(result) != value) {
+            result.duplicateArguments.put(argument.value, value)
+        }
+
         updateField(field, result, value)
     }
 }

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

@@ -136,7 +136,7 @@ public abstract class CLICompiler<A extends CommonCompilerArguments> {
             messageCollector = new FilteringMessageCollector(messageCollector, Predicate.isEqual(WARNING));
         }
 
-        reportUnknownAndObsoleteExtraFlags(messageCollector, arguments);
+        reportArgumentParseProblems(messageCollector, arguments);
 
         GroupingMessageCollector groupingCollector = new GroupingMessageCollector(messageCollector);
 
@@ -311,7 +311,7 @@ public abstract class CLICompiler<A extends CommonCompilerArguments> {
             @NotNull CompilerConfiguration configuration, @NotNull A arguments, @NotNull Services services
     );
 
-    private void reportUnknownAndObsoleteExtraFlags(@NotNull MessageCollector collector, @NotNull A arguments) {
+    private void reportArgumentParseProblems(@NotNull MessageCollector collector, @NotNull A arguments) {
         for (String flag : arguments.unknownExtraFlags) {
             collector.report(STRONG_WARNING, "Flag is not supported by this version of the compiler: " + flag, null);
         }
@@ -319,6 +319,10 @@ public abstract class CLICompiler<A extends CommonCompilerArguments> {
             collector.report(STRONG_WARNING, "Advanced option value is passed in an obsolete form. Please use the '=' character " +
                                              "to specify the value: " + argument + "=...", null);
         }
+        for (Map.Entry<String, String> argument : arguments.duplicateArguments.entrySet()) {
+            collector.report(STRONG_WARNING, "Argument " + argument.getKey() + " is passed multiple times. " +
+                                             "Only the last value will be used: " + argument.getValue(), null);
+        }
     }
 
     @NotNull

compiler/testData/cli/jvm/argumentPassedMultipleTimes.args

@@ -0,0 +1,16 @@
+$TESTDATA_DIR$/simple.kt
+-cp
+$TESTDATA_DIR$
+-cp
+$TESTDATA_DIR$
+-java-parameters
+-java-parameters
+-Xno-inline
+-d
+$TEMP_DIR$
+-java-parameters
+-Xno-inline
+-module-name
+aaa
+-module-name
+bbb

compiler/testData/cli/jvm/argumentPassedMultipleTimes.out

@@ -0,0 +1,2 @@
+warning: argument -module-name is passed multiple times. Only the last value will be used: bbb
+OK

compiler/testData/cli/jvm/coroutinesEnableWarnAndErrorClash.args

@@ -1,4 +0,0 @@
-$TESTDATA_DIR$/simple.kt
--Xcoroutines=enable
--Xcoroutines=warn
--Xcoroutines=error

compiler/testData/cli/jvm/coroutinesEnableWarnAndErrorClash.out

@@ -1,2 +0,0 @@
-error: the -Xcoroutines can only have one value
-COMPILATION_ERROR

compiler/testData/cli/jvm/coroutinesErrorAndEnable.args

@@ -1,3 +1,5 @@
 $TESTDATA_DIR$/simple.kt
 -Xcoroutines=error
--Xcoroutines=enable
+-Xcoroutines=enable
+-d
+$TEMP_DIR$

compiler/testData/cli/jvm/coroutinesErrorAndEnable.out

@@ -0,0 +1,2 @@
+warning: argument -Xcoroutines is passed multiple times. Only the last value will be used: enable
+OK

compiler/testData/cli/jvm/coroutinesErrorAndEnableClash.out

@@ -1,2 +0,0 @@
-error: the -Xcoroutines can only have one value
-COMPILATION_ERROR

compiler/testData/cli/jvm/coroutinesWarnAndEnableClash.args

@@ -1,3 +0,0 @@
-$TESTDATA_DIR$/simple.kt
--Xcoroutines=warn
--Xcoroutines=enable

compiler/testData/cli/jvm/coroutinesWarnAndEnableClash.out

@@ -1,2 +0,0 @@
-error: the -Xcoroutines can only have one value
-COMPILATION_ERROR

compiler/testData/cli/jvm/coroutinesWarnAndErrorClash.args

@@ -1,3 +0,0 @@
-$TESTDATA_DIR$/simple.kt
--Xcoroutines=warn
--Xcoroutines=error

compiler/testData/cli/jvm/coroutinesWarnAndErrorClash.out

@@ -1,2 +0,0 @@
-error: the -Xcoroutines can only have one value
-COMPILATION_ERROR

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

@@ -74,6 +74,12 @@ public class CliTestGenerated extends AbstractCliTest {
             doJvmTest(fileName);
         }
 
+        @TestMetadata("argumentPassedMultipleTimes.args")
+        public void testArgumentPassedMultipleTimes() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/cli/jvm/argumentPassedMultipleTimes.args");
+            doJvmTest(fileName);
+        }
+
         @TestMetadata("classAndFileClassClash.args")
         public void testClassAndFileClassClash() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/cli/jvm/classAndFileClassClash.args");
@@ -128,39 +134,21 @@ public class CliTestGenerated extends AbstractCliTest {
             doJvmTest(fileName);
         }
 
-        @TestMetadata("coroutinesEnableWarnAndErrorClash.args")
-        public void testCoroutinesEnableWarnAndErrorClash() throws Exception {
-            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/cli/jvm/coroutinesEnableWarnAndErrorClash.args");
-            doJvmTest(fileName);
-        }
-
         @TestMetadata("coroutinesError.args")
         public void testCoroutinesError() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/cli/jvm/coroutinesError.args");
             doJvmTest(fileName);
         }
 
-        @TestMetadata("coroutinesErrorAndEnableClash.args")
+        @TestMetadata("coroutinesErrorAndEnable.args")
-        public void testCoroutinesErrorAndEnableClash() throws Exception {
+        public void testCoroutinesErrorAndEnable() throws Exception {
-            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/cli/jvm/coroutinesErrorAndEnableClash.args");
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/cli/jvm/coroutinesErrorAndEnable.args");
             doJvmTest(fileName);
         }
 
-        @TestMetadata("coroutinesWarnAndEnableClash.args")
+        @TestMetadata("coroutinesWarn.args")
-        public void testCoroutinesWarnAndEnableClash() throws Exception {
+        public void testCoroutinesWarn() throws Exception {
-            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/cli/jvm/coroutinesWarnAndEnableClash.args");
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/cli/jvm/coroutinesWarn.args");
-            doJvmTest(fileName);
-        }
-
-        @TestMetadata("coroutinesWarnAndErrorClash.args")
-        public void testCoroutinesWarnAndErrorClash() throws Exception {
-            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/cli/jvm/coroutinesWarnAndErrorClash.args");
-            doJvmTest(fileName);
-        }
-
-        @TestMetadata("coroutinesWarninig.args")
-        public void testCoroutinesWarninig() throws Exception {
-            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/cli/jvm/coroutinesWarninig.args");
             doJvmTest(fileName);
         }