GH-1730: avoid exception due to completion being invoked beyond string literal boundaries

Author: martinlippert

headless-services/spring-boot-language-server/src/main/java/org/springframework/ide/vscode/boot/java/value/ValueCompletionProcessor.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2017, 2024 Pivotal, Inc.
+ * Copyright (c) 2017, 2025 Pivotal, Inc.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -160,6 +160,10 @@ private void computeProposalsForSimpleName(IJavaProject project, ASTNode node, C
 	}
 
 	private void computeProposalsForStringLiteral(IJavaProject project, StringLiteral node, Collection<ICompletionProposal> completions, int offset, TextDocument doc) throws BadLocationException {
+		if (node.getStartPosition() + node.getLength() <= offset) {
+			return;
+		}
+		
 		String prefix = identifyPropertyPrefix(doc.get(node.getStartPosition() + 1, offset - (node.getStartPosition() + 1)), offset - (node.getStartPosition() + 1));
 
 		int startOffset = offset - prefix.length();

headless-services/spring-boot-language-server/src/test/java/org/springframework/ide/vscode/boot/java/value/test/ValueCompletionTest.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2017, 2024 Pivotal, Inc.
+ * Copyright (c) 2017, 2025 Pivotal, Inc.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -184,6 +184,13 @@ void testEmptyBracketsCompletionWithParamName() throws Exception {
         		"@Value(value=\"classpath:org/test/random-resource-org-test.txt\"<*>)");
     }
 
+    @Test
+    void testCursorBehindStringLiteralEmptyCompletions() throws Exception {
+        prepareCase("@Value(\"onField\")", "@Value(\"something\"<*>)");
+        assertPropertyCompletions();
+        assertClasspathCompletions();
+    }
+
     @Test
     void testEmptyBracketsCompletionWithWrongParamName() throws Exception {
         prepareCase("@Value(\"onField\")", "@Value(another=<*>)");