Improve ETagRequired error range

Fixes eclipse-lemminx#876

Signed-off-by: azerr <azerr@redhat.com>

org.eclipse.lemminx/src/main/java/org/eclipse/lemminx/dom/DOMElement.java

@@ -333,6 +333,33 @@ public int getStartTagCloseOffset() {
 		return startTagCloseOffset;
 	}
 
+	public int getBestStartTagCloseOffset() {
+		if (isStartTagClosed()) {
+			return getStartTagCloseOffset();
+		}
+		String text = getOwnerDocument().getText();
+		int endOffset = text.length() - 1;
+		DOMNode nextNode = getFirstChild();
+		if (nextNode == null) {
+			nextNode = getNextSibling();
+		}
+		if (nextNode != null) {
+			endOffset = ((DOMElement) nextNode).getStartTagOpenOffset() - 1;
+		}
+		if (nextNode == null) {
+			DOMElement parent  = getParentElement();
+			if (parent != null && parent.hasEndTag()) {
+				endOffset = parent.getEndTagOpenOffset() - 1;
+			}
+		}
+		// remove spaces
+		while (Character.isWhitespace(text.charAt(endOffset))) {
+			endOffset--;
+		}
+		endOffset++;
+		return endOffset;
+	}
+
 	/**
 	 * Returns the end tag open offset and {@link DOMNode#NULL_VALUE} if it doesn't
 	 * exist.
@@ -397,12 +424,23 @@ public boolean isEndTagClosed() {
 	 * Returns true if the given element is an orphan end tag (which has no start
 	 * tag, eg: </a>) and false otherwise.
 	 * 
-	 * @param tagName the end tag name.
 	 * @return true if the given element is an orphan end tag (which has no start
 	 *         tag, eg: </a>) and false otherwise.
 	 */
-	public boolean isOrphanEndTag(String tagName) {
-		return isSameTag(tagName) && hasEndTag() && !hasStartTag();
+	public boolean isOrphanEndTag() {
+		return hasEndTag() && !hasStartTag();
+	}
+
+	/**
+	 * Returns true if the given element is an orphan end tag (which has no start
+	 * tag, eg: </a>) of the given tag name and false otherwise.
+	 * 
+	 * @param tagName the end tag name.
+	 * @return true if the given element is an orphan end tag (which has no start
+	 *         tag, eg: </a>) of the given tag name and false otherwise.
+	 */
+	public boolean isOrphanEndTagOf(String tagName) {
+		return isSameTag(tagName) && isOrphanEndTag();
 	}
 
 	@Override
@@ -423,7 +461,7 @@ public DOMElement getOrphanEndElement(int offset, String tagName) {
 		for (DOMNode child : children) {
 			if (child.isElement()) {
 				DOMElement childElement = (DOMElement) child;
-				if (childElement.isOrphanEndTag(tagName)) {
+				if (childElement.isOrphanEndTagOf(tagName)) {
 					return childElement;
 				}
 			}

org.eclipse.lemminx/src/main/java/org/eclipse/lemminx/dom/DOMNode.java

@@ -746,7 +746,7 @@ public DOMElement getOrphanEndElement(int offset, String tagName) {
 		}
 		// emp| </employe>
 		DOMElement nextElement = (DOMElement) next;
-		if (nextElement.isOrphanEndTag(tagName)) {
+		if (nextElement.isOrphanEndTagOf(tagName)) {
 			return nextElement;
 		}
 		return null;

org.eclipse.lemminx/src/main/java/org/eclipse/lemminx/dom/parser/XMLScanner.java

@@ -136,6 +136,10 @@ boolean hasNextElementName() {
 		stream.advanceWhileChar(ELEMENT_NAME_PREDICATE);
 		return true;
 	}
+
+	public static boolean isStartElementName(Integer ch) {
+		return START_ELEMENT_NAME_PREDICATE.test(ch);
+	}
 
 	/**
 	 * Returns true if the current token is an attribute name and false otherwise.

org.eclipse.lemminx/src/main/java/org/eclipse/lemminx/extensions/contentmodel/participants/XMLSchemaErrorCode.java

@@ -256,7 +256,7 @@ public static Range toLSPRange(XMLLocator location, XMLSchemaErrorCode code, Obj
 		case TargetNamespace_1:
 			return XMLPositionUtility.selectRootAttributeValue(DOMAttr.XMLNS_ATTR, document);
 		case TargetNamespace_2:
-			return XMLPositionUtility.selectRootStartTag(document);
+			return XMLPositionUtility.selectRootStartTagName(document);
 		default:
 		}
 		return null;

org.eclipse.lemminx/src/main/java/org/eclipse/lemminx/extensions/contentmodel/participants/XMLSyntaxErrorCode.java

@@ -141,19 +141,13 @@ public static Range toLSPRange(XMLLocator location, XMLSyntaxErrorCode code, Obj
 			return XMLPositionUtility.selectAttributeNameFromGivenNameAt(attrName, offset, document);
 		}
 		case MarkupEntityMismatch:
+			return XMLPositionUtility.selectRootStartTag(document);
 		case ElementUnterminated: {
 			String text = document.getText();
 			if (offset < text.length()) {
-				DOMNode element = document.findNodeAt(offset);
-				if (element.isElement() && !((DOMElement) element).isStartTagClosed()) {
-					// ex : <foo attr="" |
-					int endOffset = offset;
-					// remove spaces
-					while (Character.isWhitespace(text.charAt(endOffset))) {
-						endOffset--;
-					}
-					endOffset++;
-					return XMLPositionUtility.createRange(element.getStart() + 1, endOffset, document);
+				DOMNode node = document.findNodeAt(offset);
+				if (node.isElement()) {
+					return XMLPositionUtility.selectStartTag((DOMElement) node);
 				}
 			}
 			return XMLPositionUtility.selectRootStartTag(document);
@@ -206,7 +200,7 @@ public static Range toLSPRange(XMLLocator location, XMLSyntaxErrorCode code, Obj
 			 */
 			String text = document.getText();
 			char ch = text.charAt(offset);
-			while(Character.isWhitespace(ch)) {
+			while (Character.isWhitespace(ch)) {
 				offset--;
 				ch = text.charAt(offset);
 			}
@@ -216,7 +210,7 @@ public static Range toLSPRange(XMLLocator location, XMLSyntaxErrorCode code, Obj
 			return XMLPositionUtility.selectEndTagName(offset, document);
 		case ETagRequired: {
 			String tag = getString(arguments[0]);
-			return XMLPositionUtility.selectChildEndTag(tag, offset, document);
+			return XMLPositionUtility.selectStartTagNameOfUnclosedElement(tag, offset, document);
 		}
 		case SemicolonRequiredInReference: {
 			EntityReferenceRange range = XMLPositionUtility.selectEntityReference(offset + 1, document, false);