Replace blank messages in OptIn diagnostics #KT-51358 Fixed

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/expression/FirOptInUsageBaseChecker.kt

@@ -16,7 +16,6 @@ import org.jetbrains.kotlin.fir.declarations.*
 import org.jetbrains.kotlin.fir.declarations.utils.isLocal
 import org.jetbrains.kotlin.fir.expressions.FirConstExpression
 import org.jetbrains.kotlin.fir.expressions.FirQualifiedAccessExpression
-import org.jetbrains.kotlin.fir.references.FirResolvedNamedReference
 import org.jetbrains.kotlin.fir.resolve.fullyExpandedType
 import org.jetbrains.kotlin.fir.resolve.toFirRegularClassSymbol
 import org.jetbrains.kotlin.fir.resolve.toSymbol
@@ -207,7 +206,7 @@ object FirOptInUsageBaseChecker {
                     Experimentality.Severity.WARNING -> FirErrors.OPT_IN_USAGE to "should"
                     Experimentality.Severity.ERROR -> FirErrors.OPT_IN_USAGE_ERROR to "must"
                 }
-                val reportedMessage = message ?: "This declaration is experimental and its usage $verb be marked"
+                val reportedMessage = message?.takeIf { it.isNotBlank() } ?: "This declaration is experimental and its usage $verb be marked"
                 reporter.reportOn(element.source, diagnostic, annotationClassId.asSingleFqName(), reportedMessage, context)
             }
         }

compiler/frontend/src/org/jetbrains/kotlin/resolve/checkers/ExperimentalUsageChecker.kt

@@ -71,7 +71,7 @@ class ExperimentalUsageChecker(project: Project) : CallChecker {
         val defaultMessage: (FqName) -> String
     ) : ExperimentalityDiagnostic {
         override fun report(trace: BindingTrace, element: PsiElement, fqName: FqName, message: String?) {
-            trace.reportDiagnosticOnce(factory.on(element, fqName, message ?: defaultMessage(fqName)))
+            trace.reportDiagnosticOnce(factory.on(element, fqName, message?.takeIf { it.isNotBlank() } ?: defaultMessage(fqName)))
         }
     }
 
@@ -480,7 +480,7 @@ class ExperimentalUsageChecker(project: Project) : CallChecker {
                         Experimentality.Severity.ERROR -> Errors.OPT_IN_OVERRIDE_ERROR to "must"
                         Experimentality.Severity.FUTURE_ERROR -> Errors.OPT_IN_OVERRIDE_ERROR to "must"
                     }
-                    val message = experimentality.message
+                    val message = experimentality.message?.takeIf { it.isNotBlank() }
                         ?: "This declaration overrides experimental member of supertype " +
                         "'${member.containingDeclaration.name.asString()}' and $defaultMessageVerb be annotated " +
                         "with '@${experimentality.annotationFqName.asString()}'"

compiler/testData/cli/jvm/optInEmptyMessage.args

@@ -0,0 +1,4 @@
+$TESTDATA_DIR$/optInEmptyMessage.kt
+-d
+$TEMP_DIR$
+-opt-in=kotlin.RequiresOptIn

compiler/testData/cli/jvm/optInEmptyMessage.kt

@@ -0,0 +1,9 @@
+@RequiresOptIn(message = " ")
+annotation class EmptyMarker
+
+@EmptyMarker
+fun foo() {}
+
+fun bar() {
+    foo()
+}

compiler/testData/cli/jvm/optInEmptyMessage.out

@@ -0,0 +1,4 @@
+compiler/testData/cli/jvm/optInEmptyMessage.kt:8:5: error: this declaration is experimental and its usage must be marked with '@EmptyMarker' or '@OptIn(EmptyMarker::class)'
+    foo()
+    ^
+COMPILATION_ERROR

compiler/testData/cli/jvm/optInEmptyMessageFir.args

@@ -0,0 +1,6 @@
+$TESTDATA_DIR$/optInEmptyMessage.kt
+-d
+$TEMP_DIR$
+-opt-in=kotlin.RequiresOptIn
+-Xuse-fir
+

compiler/testData/cli/jvm/optInEmptyMessageFir.kt

@@ -0,0 +1,9 @@
+@RequiresOptIn(message = " ")
+annotation class EmptyMarker
+
+@EmptyMarker
+fun foo() {}
+
+fun bar() {
+    foo()
+}

compiler/testData/cli/jvm/optInEmptyMessageFir.out

@@ -0,0 +1,7 @@
+warning: ATTENTION!
+ This build uses in-dev FIR:
+  -Xuse-fir
+compiler/testData/cli/jvm/optInEmptyMessage.kt:8:5: error: this declaration is experimental and its usage must be marked
+    foo()
+    ^
+COMPILATION_ERROR

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

@@ -799,6 +799,16 @@ public class CliTestGenerated extends AbstractCliTest {
             runTest("compiler/testData/cli/jvm/oldBackendLv16.args");
         }
 
+        @TestMetadata("optInEmptyMessage.args")
+        public void testOptInEmptyMessage() throws Exception {
+            runTest("compiler/testData/cli/jvm/optInEmptyMessage.args");
+        }
+
+        @TestMetadata("optInEmptyMessageFir.args")
+        public void testOptInEmptyMessageFir() throws Exception {
+            runTest("compiler/testData/cli/jvm/optInEmptyMessageFir.args");
+        }
+
         @TestMetadata("pluginSimple.args")
         public void testPluginSimple() throws Exception {
             runTest("compiler/testData/cli/jvm/pluginSimple.args");