Return all fields

Author: svilen-mihaylov-elastic

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/session/FieldNameUtils.java

@@ -71,12 +71,6 @@ public static PreAnalysisResult resolveFieldNames(LogicalPlan parsed, EnrichReso
             inlinestatsAggs.add(((InlineStats) i).aggregate());
         }
 
-        if (false == parsed.anyMatch(p -> shouldCollectReferencedFields(p, inlinestatsAggs))) {
-            // no explicit columns selection, for example "from employees"
-            // also, inlinestats only adds columns to the existent output, its Aggregate shouldn't interfere with potentially using "*"
-            return new PreAnalysisResult(enrichResolution, IndexResolver.ALL_FIELDS, Set.of());
-        }
-
         Holder<Boolean> projectAll = new Holder<>(false);
         parsed.forEachExpressionDown(UnresolvedStar.class, us -> {// explicit "*" fields selection
             if (projectAll.get()) {
@@ -107,6 +101,7 @@ public static PreAnalysisResult resolveFieldNames(LogicalPlan parsed, EnrichReso
         Set<String> wildcardJoinIndices = new java.util.HashSet<>();
 
         var canRemoveAliases = new Holder<>(true);
+        var needsAllFields = new Holder<>(parsed.anyMatch(p -> shouldCollectReferencedFields(p, inlinestatsAggs)) == false);
 
         var processingLambda = new Holder<Function<LogicalPlan, Boolean>>();
         processingLambda.set((LogicalPlan p) -> {// go over each plan top-down
@@ -120,6 +115,10 @@ public static PreAnalysisResult resolveFieldNames(LogicalPlan parsed, EnrichReso
                     var return_result = child.forEachDownMayReturnEarly(processingLambda.get());
                     // No nested Forks for now...
                     assert return_result;
+                    if (referencesBuilder.get().isEmpty()) {
+                        needsAllFields.set(true);
+                        return true;
+                    }
                     forkRefsResult.addAll(referencesBuilder.get());
                 }
 
@@ -210,6 +209,12 @@ public static PreAnalysisResult resolveFieldNames(LogicalPlan parsed, EnrichReso
         });
         parsed.forEachDownMayReturnEarly(processingLambda.get());
 
+        if (needsAllFields.get()) {
+            // no explicit columns selection, for example "from employees"
+            // also, inlinestats only adds columns to the existent output, its Aggregate shouldn't interfere with potentially using "*"
+            return new PreAnalysisResult(enrichResolution, IndexResolver.ALL_FIELDS, Set.of());
+        }
+
         // Add JOIN ON column references afterward to avoid Alias removal
         referencesBuilder.get().addAll(joinRefs);
         // If any JOIN commands need wildcard field-caps calls, persist the index names

x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/session/FieldNameUtilsTests.java

@@ -59,6 +59,13 @@ public void testSimple1() {
         );
     }
 
+    public void testSimple2() {
+        assertFieldNames("""
+            FROM employees
+            | WHERE emp_no == "2"
+            """, IndexResolver.ALL_FIELDS);
+    }
+
     public void testDirectFilter() {
         assertFieldNames(
             "from employees | sort emp_no | where still_hired | keep emp_no | limit 3",
@@ -2162,7 +2169,7 @@ public void testForkWithStatsInAllBranches2() {
     public void testForkWithStatsAndWhere() {
         assertFieldNames(
             " FROM employees | FORK ( WHERE true | stats min(salary) by gender) ( WHERE true | LIMIT 3 )",
-            Set.of("gender", "salary", "gender.*", "salary.*")
+            IndexResolver.ALL_FIELDS
         );
     }
 
@@ -2180,7 +2187,7 @@ public void testNullStringWithFork() {
             | EVAL x = null::string
             | STATS COUNT() BY category=CATEGORIZE(x)
             | SORT category
-            | FORK (WHERE true) (WHERE true) | WHERE _fork == "fork1" | DROP _fork""", Set.of("_index"));
+            | FORK (WHERE true) (WHERE true) | WHERE _fork == "fork1" | DROP _fork""", IndexResolver.ALL_FIELDS);
     }
 
     public void testSingleFork() {
@@ -2189,7 +2196,7 @@ public void testSingleFork() {
             | FORK
                ( STATS x = count(*))
                ( WHERE emp_no == "2" )
-            | SORT _fork""", Set.of("emp_no", "emp_no.*"));
+            | SORT _fork""", IndexResolver.ALL_FIELDS);
     }
 
     private void assertFieldNames(String query, Set<String> expected) {