Interactive Examples Editor Error Highlighting Improvements

core/src/main/kotlin/io/specmatic/core/pattern/Discriminator.kt

@@ -79,10 +79,11 @@ class Discriminator(
         )
 
         if (isPatternToken(actualDiscriminatorValue) || ExampleProcessor.isSubstitutionToken(actualDiscriminatorValue)) return Result.Success()
-
         if (actualDiscriminatorValue.toStringLiteral() !in values) {
-            val message =
-                "Expected the value of discriminator property to be $discriminatorCsvClause but it was ${actualDiscriminatorValue.toStringLiteral()}"
+            val message = "Expected the value of discriminator property to be $discriminatorCsvClause but it was ${
+                actualDiscriminatorValue.toStringLiteral()
+                    .takeUnless { it.isEmpty() } ?: "\"\""
+            }"
 
             return Result.Failure(
                 message,

core/src/main/kotlin/io/specmatic/core/pattern/ExactValuePattern.kt

@@ -15,7 +15,9 @@ data class ExactValuePattern(override val pattern: Value, override val typeAlias
             true -> Result.Success()
             else -> {
                 if (discriminator) {
-                    val errorMessage = "Expected the value of discriminator property to be ${pattern.displayableValue()} but it was ${sampleData?.displayableValue()}"
+                    val errorMessage = "Expected the value of discriminator property to be ${pattern.displayableValue()} but it was ${
+                        sampleData?.displayableValue().takeUnless { it.isNullOrEmpty() } ?: "\"\""
+                    }"
                     Result.Failure(errorMessage, failureReason = FailureReason.DiscriminatorMismatch)
                 } else
                     mismatchResult(pattern, sampleData, resolver.mismatchMessages)

core/src/main/resources/static/example-server.js

@@ -630,15 +630,15 @@ function createExampleDropDown(example) {
                 decorationsField,
                 editorFacet,
                 window.EditorView.updateListener.of((update) => {
-                    if (update.docChanged) {
-                        isSaved = false;
-                        const editorElement = editor.dom;
-                        updateBorderColorExampleBlock(editorElement, examplePreDiv);
-                        if (example.errorList && example.errorList.length > 0) {
-                            highlightErrorLines(editor, example.errorList, example.exampleJson);
-                        }
-                        savedEditorResponse = update.state.doc.toString();
-                    }
+                  if (!update.docChanged) return;
+                  const docContent = update.state.doc.toString();
+
+                  isSaved = false;
+                  const editorElement = editor.dom;
+                  updateBorderColorExampleBlock(editorElement, examplePreDiv);
+                  if (!example.errorList.length > 0) return;
+                  highlightErrorLines(editor, example.errorList, docContent);
+                  savedEditorResponse = docContent;
                 })
             ],
         }),
@@ -746,15 +746,20 @@ function highlightErrorLines(editor, metadata, exampleJson) {
             existingMarkers.get(lineNumber).push(meta.description);
             const combinedDescriptions = existingMarkers.get(lineNumber).join('\n\n');
             const className = "specmatic-editor-line-error";
+            const tokenStart = lineLength.from;
+            const tokenEnd = lineLength.to;
+            const existingDecoration = decorations.filter(decoration => decoration.from === tokenStart && decoration.to === tokenEnd);
+            if (existingDecoration.length !== 0) return;
 
             decorations.push(
-                window.Decoration.line({
+                window.Decoration.mark({
                     class: className,
                     attributes: {
                         "data-validation-error-message": combinedDescriptions
                     }
-                }).range(lineLength.from)
+                }).range(tokenStart, tokenEnd)
             );
+
             const existingError = errorMetadata.find(err => err.line === lineNumber + 1);
             if (existingError) {
                 existingError.message = combinedDescriptions;
@@ -768,6 +773,7 @@ function highlightErrorLines(editor, metadata, exampleJson) {
         }
     });
     decorations.sort((a, b) => a.from - b.from);
+
     const decorationSet = window.Decoration.set(decorations);
     const transaction = editor.state.update({
         effects: setDecorationsEffect.of(decorationSet)