Issue 638 - Now when we stop automatically collection completions fro…

…m other contributors, we still execute all remaining contributors but don't add completions that are duplicates (in terms of the lookup string) of what has already been added in a first-class manner from LSP. This addresses both the unit test failure which was due to a missing active lookup from having stopped completions early and the concerns about not collecting valid completions from other contributors.

src/main/java/com/redhat/devtools/lsp4ij/features/completion/LSPCompletionContributor.java

@@ -21,23 +21,22 @@
 import com.intellij.openapi.progress.ProgressManager;
 import com.intellij.openapi.vfs.VirtualFile;
 import com.intellij.psi.PsiFile;
+import com.intellij.util.containers.ContainerUtil;
 import com.redhat.devtools.lsp4ij.LSPFileSupport;
 import com.redhat.devtools.lsp4ij.LSPIJUtils;
 import com.redhat.devtools.lsp4ij.LanguageServerItem;
 import com.redhat.devtools.lsp4ij.client.ExecuteLSPFeatureStatus;
-import com.redhat.devtools.lsp4ij.client.indexing.ProjectIndexingManager;
 import com.redhat.devtools.lsp4ij.client.features.LSPCompletionFeature;
 import com.redhat.devtools.lsp4ij.client.features.LSPCompletionProposal;
+import com.redhat.devtools.lsp4ij.client.indexing.ProjectIndexingManager;
 import org.eclipse.lsp4j.*;
 import org.eclipse.lsp4j.jsonrpc.messages.Either;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.List;
+import java.util.*;
 import java.util.concurrent.CancellationException;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ExecutionException;
@@ -125,6 +124,7 @@ private void addCompletionItems(@NotNull CompletionParameters parameters,
         items.sort(completionProposalComparator);
         int size = items.size();
 
+        Set<String> addedLookupStrings = new HashSet<>();
         var completionFeature = languageServer.getClientFeatures().getCompletionFeature();
         LSPCompletionFeature.LSPCompletionContext context = new LSPCompletionFeature.LSPCompletionContext(parameters, languageServer);
         // Items now sorted by priority, low index == high priority
@@ -137,13 +137,25 @@ private void addCompletionItems(@NotNull CompletionParameters parameters,
             LookupElement lookupItem = completionFeature.createLookupElement(item, context);
             if (lookupItem != null) {
                completionFeature.addLookupItem(completionPrefix, result, lookupItem, size- i, item);
+                ContainerUtil.addIfNotNull(addedLookupStrings, lookupItem.getLookupString());
             }
         }
 
         // If completions were added from LSP and this is auto-completion or the explicit completion trigger was typed
-        // only once, don't show completions from other contributors, specifically the word completion contributor
+        // only once, add completions from other contributors carefully to avoid duplicates, specifically from the word
+        // completion contributor
         if ((size > 0) && (parameters.getInvocationCount() < 2)) {
             result.stopHere();
+            result.runRemainingContributors(parameters, completionResult -> {
+                LookupElement lookupElement = completionResult.getLookupElement();
+                if (lookupElement != null) {
+                    String lookupString = lookupElement.getLookupString();
+                    if (!addedLookupStrings.contains(lookupString)) {
+                        result.consume(lookupElement);
+                        addedLookupStrings.add(lookupString);
+                    }
+                }
+            });
         }
     }