GH-1560: avoid duplicate property keys in completion proposala

Fixes GH-1560

Author: martinlippert

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

@@ -12,6 +12,7 @@
 
 import java.util.ArrayList;
 import java.util.Collections;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
 import java.util.TreeSet;
@@ -66,10 +67,11 @@ else if (Mode.PREFIX == this.mode) {
 
 	private List<AnnotationAttributeProposal> findProperties(IJavaProject project, String prefix) {
 		List<AnnotationAttributeProposal> result = new ArrayList<>();
+		Set<String> propertyKeys = new HashSet<>();
 
 		// First the 'real' properties, Then also add 'ad-hoc' properties
-		addPropertyProposals(indexProvider.getIndex(project).getProperties(), prefix, result);
-		addPropertyProposals(adHocIndexProvider.getIndex(project), prefix, result);
+		addPropertyProposals(indexProvider.getIndex(project).getProperties(), prefix, result, propertyKeys);
+		addPropertyProposals(adHocIndexProvider.getIndex(project), prefix, result, propertyKeys);
 
 		result.sort((p1, p2) -> p1.getLabel().compareTo(p2.getLabel()));
 
@@ -86,9 +88,14 @@ private List<AnnotationAttributeProposal> findPrefixes(IJavaProject project) {
 		return new ArrayList<>(prefixes);
 	}
 
-	private void addPropertyProposals(FuzzyMap<PropertyInfo> properties, String prefix, List<AnnotationAttributeProposal> result) {
+	private void addPropertyProposals(FuzzyMap<PropertyInfo> properties, String prefix, List<AnnotationAttributeProposal> result, Set<String> propertyKeys) {
 		properties.forEach(propertyInfo -> {
 			String propID = propertyInfo.getId();
+
+			// avoid duplicate property keys
+			if (!propertyKeys.add(propID)) {
+				return;
+			}
 
 			if (prefix != null) {				
 				if (prefix.length() > 0

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

@@ -147,6 +147,31 @@ public void testConditionalOnPropertyCompletionWithoutPrefix() throws Exception
         assertEquals("spring.boot.prop1", completions.get(2).getLabel());
     }
 
+    @Test
+    public void testConditionalOnPropertyCompletionWithAdhocProperties() throws Exception {
+    	adHocProperties.add("adhoc.prop");
+    	
+        List<CompletionItem> completions = getCompletions("@ConditionalOnProperty(<*>)");
+        assertEquals(4, completions.size());
+        
+        assertEquals("adhoc.prop", completions.get(0).getLabel());
+        assertEquals("data.prop2", completions.get(1).getLabel());
+        assertEquals("else.prop3", completions.get(2).getLabel());
+        assertEquals("spring.boot.prop1", completions.get(3).getLabel());
+    }
+
+    @Test
+    public void testConditionalOnPropertyCompletionWithAdhocPropertiesDuplicatedKey() throws Exception {
+    	adHocProperties.add("data.prop2");
+    	
+        List<CompletionItem> completions = getCompletions("@ConditionalOnProperty(<*>)");
+        assertEquals(3, completions.size());
+        
+        assertEquals("data.prop2", completions.get(0).getLabel());
+        assertEquals("else.prop3", completions.get(1).getLabel());
+        assertEquals("spring.boot.prop1", completions.get(2).getLabel());
+    }
+
     @Test
     public void testConditionalOnPropertyCompletionWithoutPrefixAttributeWithNameAttribute() throws Exception {
         List<CompletionItem> completions = getCompletions("@ConditionalOnProperty(name=<*>)");