ESQL: Better management of not stored TEXT fiels with synthetic source (#99695)

docs/changelog/99695.yaml

@@ -0,0 +1,5 @@
+pr: 99695
+summary: "ESQL: Better management of not stored TEXT fiels with synthetic source"
+area: ES|QL
+type: bug
+issues: []

x-pack/plugin/esql/compute/src/main/java/org/elasticsearch/compute/lucene/ValueSources.java

@@ -60,7 +60,7 @@ public final class ValueSources {
                 // MatchOnlyTextFieldMapper class lives in the mapper-extras module. We use string equality
                 // for the field type name to avoid adding a dependency to the module
                 if (fieldType instanceof KeywordFieldMapper.KeywordFieldType
-                    || fieldType instanceof TextFieldMapper.TextFieldType
+                    || fieldType instanceof TextFieldMapper.TextFieldType tft && (tft.isSyntheticSource() == false || tft.isStored())
                     || MATCH_ONLY_TEXT.equals(fieldType.typeName())) {
                     ValuesSource vs = textValueSource(ctx, fieldType);
                     sources.add(new ValueSourceInfo(CoreValuesSourceType.KEYWORD, vs, elementType, ctx.getIndexReader()));

x-pack/plugin/esql/qa/server/single-node/src/yamlRestTest/resources/rest-api-spec/test/80_text.yml

@@ -323,9 +323,7 @@ setup:
 ---
 "text with synthetic source":
   - skip:
-      version: "all"
-      reason: "AwaitsFix https://github.com/elastic/elasticsearch/issues/99183"
-
+      features: allowed_warnings_regex
   - do:
       indices.create:
         index: test2
@@ -355,6 +353,8 @@ setup:
           - { "emp_no": 20, "name": "John", "job": "Payroll Specialist" }
 
   - do:
+      allowed_warnings_regex:
+        - "Field \\[job\\] cannot be retrieved, it is unsupported or not indexed; returning null"
       esql.query:
         body:
           query: 'from test2 | sort emp_no | keep job'
@@ -363,8 +363,8 @@ setup:
   - match: { columns.0.type: "text" }
 
   - length: { values: 2 }
-  - match: { values.0.0: "IT Director" }
-  - match: { values.1.0: "Payroll Specialist" }
+  - match: { values.0.0: null } # awaiting a complete fix for https://github.com/elastic/elasticsearch/issues/99183
+  - match: { values.1.0: null } # for now, since we cannot extract text values from synthetic source, we at least avoid to throw exceptions
 
 
 ---