fix(graphql-language-service): return null instead of empty contents array when hover results are empty (#3913)

* fix(graphql-language-service): return `null` instead of empty `contents`

* Create wild-paws-smash.md

---------

Co-authored-by: Dimitri POSTOLOV <[email protected]>

Author: joshbode

.changeset/wild-paws-smash.md

@@ -0,0 +1,5 @@
+---
+"graphql-language-service-server": patch
+---
+
+return `null` instead of an empty `contents` array when hover results are empty

packages/graphql-language-service-server/src/MessageProcessor.ts

@@ -656,9 +656,9 @@ export class MessageProcessor {
 
   public async handleHoverRequest(
     params: TextDocumentPositionParams,
-  ): Promise<Hover> {
+  ): Promise<Hover | null> {
     if (!this._isInitialized) {
-      return { contents: [] };
+      return null;
     }
 
     this.validateDocumentAndPosition(params);
@@ -667,7 +667,7 @@ export class MessageProcessor {
 
     const cachedDocument = this._getCachedDocument(textDocument.uri);
     if (!cachedDocument) {
-      return { contents: [] };
+      return null;
     }
 
     const found = cachedDocument.contents.find(content => {
@@ -679,7 +679,7 @@ export class MessageProcessor {
 
     // If there is no GraphQL query in this file, return an empty result.
     if (!found) {
-      return { contents: [] };
+      return null;
     }
 
     const { query, range } = found;

packages/graphql-language-service-server/src/__tests__/MessageProcessor.test.ts

@@ -553,7 +553,7 @@ describe('MessageProcessor', () => {
     messageProcessor._getCachedDocument = (_uri: string) => null;
 
     const result = await messageProcessor.handleHoverRequest(test);
-    expect(result).toEqual({ contents: [] });
+    expect(result).toBeNull();
   });
   it('handles provided config', async () => {
     const msgProcessor = new MessageProcessor({