Use kotlin.Lazy for script definition computation, add test for no definition

compiler/frontend/src/org/jetbrains/kotlin/psi/KtScript.java

@@ -18,6 +18,8 @@ package org.jetbrains.kotlin.psi;
 
 import com.intellij.lang.ASTNode;
 import com.intellij.psi.util.PsiTreeUtil;
+import kotlin.Lazy;
+import kotlin.LazyKt;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.kotlin.name.FqName;
 import org.jetbrains.kotlin.psi.stubs.KotlinScriptStub;
@@ -26,21 +28,15 @@ import org.jetbrains.kotlin.script.KotlinScriptDefinition;
 import org.jetbrains.kotlin.script.KotlinScriptDefinitionProviderKt;
 
 import java.util.List;
+import java.util.Objects;
+
+import static kotlin.LazyThreadSafetyMode.PUBLICATION;
 
 public class KtScript extends KtNamedDeclarationStub<KotlinScriptStub> implements KtDeclarationContainer {
-
-    private KotlinScriptDefinition kotlinScriptDefinitionField = null;
-    private boolean kotlinScriptDefinitionInitialized = false;
-
-    // make it a simple lazy value after converting to kotlin
-    private KotlinScriptDefinition getKotlinScriptDefinition() {
-        if (!kotlinScriptDefinitionInitialized) {
-            kotlinScriptDefinitionField = KotlinScriptDefinitionProviderKt.getScriptDefinition(getContainingKtFile());
-            kotlinScriptDefinitionInitialized = true;
-        }
-        assert kotlinScriptDefinitionField != null : "Should not parse a script without definition: " + getContainingKtFile().toString();
-        return kotlinScriptDefinitionField;
-    }
+    private final Lazy<KotlinScriptDefinition> kotlinScriptDefinition = LazyKt.lazy(PUBLICATION, () -> Objects.requireNonNull(
+            KotlinScriptDefinitionProviderKt.getScriptDefinition(getContainingKtFile()),
+            () -> "Should not parse a script without definition: " + getContainingKtFile().getVirtualFile().getPath()
+    ));
 
     public KtScript(@NotNull ASTNode node) {
         super(node);
@@ -58,7 +54,7 @@ public class KtScript extends KtNamedDeclarationStub<KotlinScriptStub> implement
             return stub.getFqName();
         }
         KtFile containingKtFile = getContainingKtFile();
-        return containingKtFile.getPackageFqName().child(getKotlinScriptDefinition().getScriptName(this));
+        return containingKtFile.getPackageFqName().child(kotlinScriptDefinition.getValue().getScriptName(this));
     }
 
     @Override
@@ -67,7 +63,7 @@ public class KtScript extends KtNamedDeclarationStub<KotlinScriptStub> implement
     }
 
     @NotNull
-    public KtBlockExpression getBlockExpression() {
+    private KtBlockExpression getBlockExpression() {
         return findNotNullChildByClass(KtBlockExpression.class);
     }
 

compiler/tests/org/jetbrains/kotlin/scripts/ScriptTemplateTest.kt

@@ -31,6 +31,7 @@ import org.jetbrains.kotlin.script.*
 import org.jetbrains.kotlin.test.ConfigurationKind
 import org.jetbrains.kotlin.test.KotlinTestUtils
 import org.jetbrains.kotlin.test.TestJdkKind
+import org.jetbrains.kotlin.util.KotlinFrontEndException
 import org.jetbrains.kotlin.utils.PathUtil
 import org.junit.Assert
 import org.junit.Test
@@ -251,6 +252,20 @@ class ScriptTemplateTest {
         Assert.assertTrue(exceptionThrown)
     }
 
+    @Test
+    fun testScriptWithNoMatchingTemplate() {
+        try {
+            compileScript("fib.kts", ScriptWithDifferentFileNamePattern::class, null)
+            Assert.fail("should throw compilation error")
+        }
+        catch (e: KotlinFrontEndException) {
+            if (e.message?.contains("Should not parse a script without definition") != true) {
+                // unexpected error
+                throw e
+            }
+        }
+    }
+
     private fun compileScript(
             scriptPath: String,
             scriptTemplate: KClass<out Any>,
@@ -387,6 +402,12 @@ abstract class ScriptWithoutParams(num: Int)
         resolver = TestKotlinScriptDependenciesResolver::class)
 abstract class ScriptBaseClassWithOverriddenProperty(override val num: Int) : TestClassWithOverridableProperty(num)
 
+@ScriptTemplateDefinition(
+        scriptFilePattern = ".*\\.custom\\.kts",
+        resolver = TestKotlinScriptDependenciesResolver::class
+)
+abstract class ScriptWithDifferentFileNamePattern
+
 @ScriptTemplateDefinition(resolver = TestKotlinScriptDependenciesResolver::class)
 abstract class ScriptWithArrayParam(val myArgs: Array<String>)