Improve error message when amending a property with no value set (#1867)

Improve error message when amending a property with no value set

This decorates error messages with the amendment node.

pkl-core/src/main/java/org/pkl/core/ast/expression/literal/EmptyObjectLiteralNode.java

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2026 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -15,11 +15,13 @@
  */
 package org.pkl.core.ast.expression.literal;
 
+import com.oracle.truffle.api.CompilerDirectives;
 import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
 import com.oracle.truffle.api.dsl.Fallback;
 import com.oracle.truffle.api.dsl.ImportStatic;
 import com.oracle.truffle.api.dsl.NodeChild;
 import com.oracle.truffle.api.dsl.Specialization;
+import com.oracle.truffle.api.frame.VirtualFrame;
 import com.oracle.truffle.api.source.SourceSection;
 import org.pkl.core.ast.ExpressionNode;
 import org.pkl.core.runtime.*;
@@ -32,6 +34,8 @@ public abstract class EmptyObjectLiteralNode extends ExpressionNode {
     super(sourceSection);
   }
 
+  protected abstract Object executeWithParent(VirtualFrame frame, Object parent);
+
   protected abstract ExpressionNode getParentNode();
 
   @Specialization
@@ -69,4 +73,26 @@ public abstract class EmptyObjectLiteralNode extends ExpressionNode {
     VmUtils.checkIsInstantiable(VmUtils.getClass(parent), getParentNode());
     throw exceptionBuilder().unreachableCode().build();
   }
+
+  @Override
+  public final Object executeGeneric(VirtualFrame frame) {
+    Object parent;
+    try {
+      parent = getParentNode().executeGeneric(frame);
+    } catch (VmException e) {
+      CompilerDirectives.transferToInterpreter();
+      // include object amendment in the error message if error found during eval of parent
+      if (e.getSourceSection() != null
+          && !e.getSourceSection().equals(sourceSection)
+          // don't include if the originating error's source section is within the bounds of our own
+          // source section.
+          && !(VmUtils.sourceSectionContains(sourceSection, e.getSourceSection()))) {
+        e.getInsertedStackFrames()
+            .putIfAbsent(
+                getRootNode().getCallTarget(), VmUtils.createStackFrame(sourceSection, null));
+      }
+      throw e;
+    }
+    return executeWithParent(frame, parent);
+  }
 }

pkl-core/src/main/java/org/pkl/core/ast/expression/literal/ObjectLiteralNode.java

@@ -28,6 +28,7 @@ import org.pkl.core.ast.type.TypeNode;
 import org.pkl.core.ast.type.UnresolvedTypeNode;
 import org.pkl.core.runtime.BaseModule;
 import org.pkl.core.runtime.VmClass;
+import org.pkl.core.runtime.VmException;
 import org.pkl.core.runtime.VmFunction;
 import org.pkl.core.runtime.VmLanguage;
 import org.pkl.core.runtime.VmNull;
@@ -58,6 +59,8 @@ public abstract class ObjectLiteralNode extends ExpressionNode {
     this.parameterTypes = parameterTypes;
   }
 
+  protected abstract Object executeWithParent(VirtualFrame frame, Object parent);
+
   protected abstract ExpressionNode getParentNode();
 
   protected abstract ObjectLiteralNode copy(ExpressionNode newParentNode);
@@ -114,4 +117,27 @@ public abstract class ObjectLiteralNode extends ExpressionNode {
     LoopNode.reportLoopCount(this, count);
     return value;
   }
+
+  @Override
+  public final Object executeGeneric(VirtualFrame frame) {
+    Object parent;
+    try {
+      parent = getParentNode().executeGeneric(frame);
+    } catch (VmException e) {
+      CompilerDirectives.transferToInterpreter();
+      // include object amendment in the error message if error found during eval of parent
+      if (e.getSourceSection() != null
+          && !e.getSourceSection().equals(sourceSection)
+          // don't include if the originating error's source section is within the bounds of our own
+          // source section.
+          && !(VmUtils.sourceSectionContains(sourceSection, e.getSourceSection()))) {
+        e.getInsertedStackFrames()
+            .putIfAbsent(
+                getRootNode().getCallTarget(),
+                VmUtils.createStackFrame(sourceSection, qualifiedScopeName));
+      }
+      throw e;
+    }
+    return executeWithParent(frame, parent);
+  }
 }

pkl-core/src/main/java/org/pkl/core/runtime/VmUtils.java

@@ -1166,4 +1166,12 @@ public final class VmUtils {
 
     return builder.toString();
   }
+
+  public static boolean sourceSectionContains(SourceSection thisSource, SourceSection otherSource) {
+    if (!thisSource.getSource().equals(otherSource.getSource())) {
+      return false;
+    }
+    return thisSource.getCharIndex() <= otherSource.getCharIndex()
+        && thisSource.getCharEndIndex() >= otherSource.getCharEndIndex();
+  }
 }

pkl-core/src/test/files/LanguageSnippetTests/input/errors/amendPropertyWithNoDefault1.pkl

@@ -0,0 +1,7 @@
+class Example {
+  aa: Listing<String> | String
+}
+
+res: Example = new {
+  aa { "hello" }
+}

pkl-core/src/test/files/LanguageSnippetTests/input/errors/amendPropertyWithNoDefault2.pkl

@@ -0,0 +1,9 @@
+open class Parent {
+  bb: *String | Int
+}
+
+class Example extends Parent {
+  bb {}
+}
+
+res: Example = new {}

pkl-core/src/test/files/LanguageSnippetTests/input/errors/amendPropertyWithNoDefault3.pkl

@@ -0,0 +1,8 @@
+class Example {
+  aa: Listing<String> | String
+  bb: Listing<String> = aa
+}
+
+res: Example = new {
+  bb {}
+}

pkl-core/src/test/files/LanguageSnippetTests/output/errors/amendPropertyWithNoDefault1.err

@@ -0,0 +1,20 @@
+–– Pkl Error ––
+Tried to read property `aa` but its value is undefined.
+
+x | aa: Listing<String> | String
+    ^^
+at amendPropertyWithNoDefault1#Example.aa (file:///$snippetsDir/input/errors/amendPropertyWithNoDefault1.pkl)
+
+The above error occurred when rendering path `res.aa` of module `file:///$snippetsDir/input/errors/amendPropertyWithNoDefault1.pkl`.
+
+x | aa { "hello" }
+    ^^^^^^^^^^^^^^
+at amendPropertyWithNoDefault1#res.aa (file:///$snippetsDir/input/errors/amendPropertyWithNoDefault1.pkl)
+
+xxx | renderer.renderDocument(value)
+      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+at pkl.base#Module.output.text (pkl:base)
+
+xxx | if (renderer is BytesRenderer) renderer.renderDocument(value) else text.encodeToBytes("UTF-8")
+                                                                         ^^^^
+at pkl.base#Module.output.bytes (pkl:base)

pkl-core/src/test/files/LanguageSnippetTests/output/errors/amendPropertyWithNoDefault2.err

@@ -0,0 +1,20 @@
+–– Pkl Error ––
+Tried to read property `bb` but its value is undefined.
+
+x | bb: *String | Int
+    ^^
+at amendPropertyWithNoDefault2#Parent.bb (file:///$snippetsDir/input/errors/amendPropertyWithNoDefault2.pkl)
+
+The above error occurred when rendering path `res.bb` of module `file:///$snippetsDir/input/errors/amendPropertyWithNoDefault2.pkl`.
+
+x | bb {}
+    ^^^^^
+at <unknown> (file:///$snippetsDir/input/errors/amendPropertyWithNoDefault2.pkl)
+
+xxx | renderer.renderDocument(value)
+      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+at pkl.base#Module.output.text (pkl:base)
+
+xxx | if (renderer is BytesRenderer) renderer.renderDocument(value) else text.encodeToBytes("UTF-8")
+                                                                         ^^^^
+at pkl.base#Module.output.bytes (pkl:base)

pkl-core/src/test/files/LanguageSnippetTests/output/errors/amendPropertyWithNoDefault3.err

@@ -0,0 +1,24 @@
+–– Pkl Error ––
+Tried to read property `aa` but its value is undefined.
+
+x | aa: Listing<String> | String
+    ^^
+at amendPropertyWithNoDefault3#Example.aa (file:///$snippetsDir/input/errors/amendPropertyWithNoDefault3.pkl)
+
+The above error occurred when rendering path `res.aa` of module `file:///$snippetsDir/input/errors/amendPropertyWithNoDefault3.pkl`.
+
+x | bb: Listing<String> = aa
+                          ^^
+at amendPropertyWithNoDefault3#Example.bb (file:///$snippetsDir/input/errors/amendPropertyWithNoDefault3.pkl)
+
+x | bb {}
+    ^^^^^
+at <unknown> (file:///$snippetsDir/input/errors/amendPropertyWithNoDefault3.pkl)
+
+xxx | renderer.renderDocument(value)
+      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+at pkl.base#Module.output.text (pkl:base)
+
+xxx | if (renderer is BytesRenderer) renderer.renderDocument(value) else text.encodeToBytes("UTF-8")
+                                                                         ^^^^
+at pkl.base#Module.output.bytes (pkl:base)