[ES|QL] Fix error handling for ES|QL nested error messages (#170005)

## Summary

Fix #170004

This PR fixes the wrong behaviour with message extraction from this type
of ES|QL responses.
Took also the opportunity to improve the FTR side, with some monaco
handlers for errors in the editor and some test cases for errors in
ES|QL queries.


### Checklist

- [x] [Unit or functional
tests](https://www.elastic.co/guide/en/kibana/master/development-tests.html)
were updated or added to match the most common scenarios

---------

Co-authored-by: kibanamachine <[email protected]>

src/plugins/data/common/search/expressions/esql.ts

@@ -71,6 +71,16 @@ function sanitize(value: string) {
   return value.replace(/[\(\)]/g, '_');
 }
 
+function extractTypeAndReason(attributes: any): { type?: string; reason?: string } {
+  if (['type', 'reason'].every((prop) => prop in attributes)) {
+    return attributes;
+  }
+  if ('error' in attributes) {
+    return extractTypeAndReason(attributes.error);
+  }
+  return {};
+}
+
 interface ESQLSearchParams {
   time_zone?: string;
   query: string;
@@ -199,7 +209,7 @@ export const getEsqlFn = ({ getStartDependencies }: EsqlFnArguments) => {
               if (!error.err) {
                 error.message = `Unexpected error from Elasticsearch: ${error.message}`;
               } else {
-                const { type, reason } = error.err.attributes;
+                const { type, reason } = extractTypeAndReason(error.err.attributes);
                 if (type === 'parsing_exception') {
                   error.message = `Couldn't parse Elasticsearch ES|QL query. Check your query and try again. Error: ${reason}`;
                 } else {

test/functional/apps/discover/group4/_esql_view.ts

@@ -134,5 +134,32 @@ export default function ({ getService, getPageObjects }: FtrProviderContext) {
         expect(await cell.getVisibleText()).to.be('1');
       });
     });
+    describe('errors', () => {
+      it('should error messages for syntax errors in query', async function () {
+        await PageObjects.discover.selectTextBaseLang();
+        const brokenQueries = [
+          'from logstash-* | limit 10*',
+          'from logstash-* | limit A',
+          'from logstash-* | where a*',
+          'limit 10',
+        ];
+        for (const testQuery of brokenQueries) {
+          await monacoEditor.setCodeEditorValue(testQuery);
+          await testSubjects.click('querySubmitButton');
+          await PageObjects.header.waitUntilLoadingHasFinished();
+          await PageObjects.discover.waitUntilSearchingHasFinished();
+          // error in fetching documents because of the invalid query
+          await testSubjects.existOrFail('discoverNoResultsError');
+          const message = await testSubjects.getVisibleText('discoverErrorCalloutMessage');
+          expect(message).to.contain(
+            "[esql] > Couldn't parse Elasticsearch ES|QL query. Check your query and try again."
+          );
+          expect(message).to.not.contain('undefined');
+          if (message.includes('line')) {
+            expect((await monacoEditor.getCurrentMarkers('kibanaCodeEditor')).length).to.eql(1);
+          }
+        }
+      });
+    });
   });
 }

test/functional/services/monaco_editor.ts

@@ -12,6 +12,7 @@ export class MonacoEditorService extends FtrService {
   private readonly retry = this.ctx.getService('retry');
   private readonly browser = this.ctx.getService('browser');
   private readonly testSubjects = this.ctx.getService('testSubjects');
+  private readonly findService = this.ctx.getService('find');
 
   public async waitCodeEditorReady(containerTestSubjId: string) {
     const editorContainer = await this.testSubjects.find(containerTestSubjId);
@@ -52,4 +53,10 @@ export class MonacoEditorService extends FtrService {
       );
     });
   }
+
+  public async getCurrentMarkers(testSubjId: string) {
+    return this.findService.allByCssSelector(
+      `[data-test-subj="${testSubjId}"] .cdr.squiggly-error`
+    );
+  }
 }