🐛 Fix wrong suggestions following an invalid literal (#72)

* ✅ Add a test for suggestions after an invalid literal

* 🐛 Fix wrong suggestions following an invalid literal

* 📚 Document literal suggestion fix in CHANGELOG

Co-authored-by: Alexander Söderberg <sauilitired@gmail.com>

CHANGELOG.md

@@ -11,6 +11,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
  - Fixed quoted parsing in StringArgument
+ - Fixed wrong suggestions following invalid literals
 
 ## [1.0.1] - 2020-10-14
 

cloud-core/src/main/java/cloud/commandframework/CommandTree.java

@@ -541,14 +541,23 @@ public final class CommandTree<C> {
                         }
                     }
                 }
+                if (commandQueue.size() > 1) {
+                    /*
+                     * In this case we were unable to match any of the literals, and so we cannot
+                     * possibly attempt to match any of its children (which is what we want, according
+                     * to the input queue). Because of this, we terminate immediately
+                     */
+                    return Collections.emptyList();
+                }
             }
             final List<String> suggestions = new LinkedList<>();
             for (final Node<CommandArgument<C, ?>> argument : root.getChildren()) {
                 if (argument.getValue() == null || this.isPermitted(commandContext.getSender(), argument) != null) {
                     continue;
                 }
-                suggestions.addAll(argument.getValue().getSuggestionsProvider()
+                final List<String> suggestionsToAdd = argument.getValue().getSuggestionsProvider()
-                        .apply(commandContext, stringOrEmpty(commandQueue.peek())));
+                        .apply(commandContext, stringOrEmpty(commandQueue.peek()));
+                suggestions.addAll(suggestionsToAdd);
             }
             return suggestions;
         }

cloud-core/src/test/java/cloud/commandframework/CommandSuggestionsTest.java

@@ -191,6 +191,19 @@ public class CommandSuggestionsTest {
         Assertions.assertEquals(Arrays.asList("5", "6", "7", "8", "9"), suggestions5);
     }
 
+    @Test
+    void testInvalidLiteralThenSpace() {
+        final String input = "test o";
+        final List<String> suggestions = manager.suggest(new TestCommandSender(), input);
+        Assertions.assertEquals(Collections.singletonList("one"), suggestions);
+        final String input2 = "test o ";
+        final List<String> suggestions2 = manager.suggest(new TestCommandSender(), input2);
+        Assertions.assertEquals(Collections.emptyList(), suggestions2);
+        final String input3 = "test o abc123xyz";
+        final List<String> suggestions3 = manager.suggest(new TestCommandSender(), input3);
+        Assertions.assertEquals(Collections.emptyList(), suggestions3);
+    }
+
 
     public enum TestEnum {
         FOO,