implicit casting for union typed field in logical plan

Author: fang-xing-esql

x-pack/plugin/esql/qa/server/src/main/java/org/elasticsearch/xpack/esql/qa/rest/FieldExtractorTestCase.java

@@ -937,6 +937,9 @@ public void testLongIntegerConflict() throws IOException {
             "order of fields in error message inconsistent before 8.14",
             getCachedNodesVersions().stream().allMatch(v -> Version.fromString(v).onOrAfter(Version.V_8_14_0))
         );
+        if (EsqlCapabilities.Cap.IMPLICIT_CASTING_UNION_TYPED_NUMERIC_AND_DATE.isEnabled()) {
+            return;
+        }
         longTest().sourceMode(SourceMode.DEFAULT).createIndex("test1", "emp_no");
         index("test1", """
             {"emp_no": 1}""");
@@ -979,6 +982,9 @@ public void testIntegerShortConflict() throws IOException {
             "order of fields in error message inconsistent before 8.14",
             getCachedNodesVersions().stream().allMatch(v -> Version.fromString(v).onOrAfter(Version.V_8_14_0))
         );
+        if (EsqlCapabilities.Cap.IMPLICIT_CASTING_UNION_TYPED_NUMERIC_AND_DATE.isEnabled()) {
+            return;
+        }
         intTest().sourceMode(SourceMode.DEFAULT).createIndex("test1", "emp_no");
         index("test1", """
             {"emp_no": 1}""");

x-pack/plugin/esql/qa/testFixtures/src/main/resources/data/employees_incompatible.csv

@@ -1296,14 +1296,3 @@ diff_sec:integer | diff_sec_m:integer | n:date_nanos
 -18489600        | -18489599        | 2023-03-23T12:15:03.360103847Z
 -18489600        | -18489599        | 2023-03-23T12:15:03.360103847Z
 ;
-
-DateAndDateNanos
-from employees,employees_incompatible
-| keep emp_no, birth_date
-| sort emp_no
-| limit 1
-;
-
-emp_no:integer |birth_date:date
-10001          |1953-09-02T00:00:00Z
-;

x-pack/plugin/esql/qa/testFixtures/src/main/resources/date_nanos.csv-spec

@@ -1639,3 +1639,67 @@ id:integer | name:keyword | count:long
 13         | lllll        | 2
 14         | mmmmm        | 2
 ;
+
+MultiTypedFieldsKeepDropSort
+required_capability: implicit_casting_union_typed_numeric_and_date
+
+FROM employees, employees_incompatible
+| DROP salary
+| KEEP emp_no, languages, hire_date, avg_worked_seconds
+| SORT emp_no, hire_date
+| limit 2
+;
+
+emp_no:long |languages:integer |hire_date:date_nanos     |avg_worked_seconds:unsigned_long
+10001       |2                 |1986-06-26T00:00:00.000Z |268728049
+10001       |2                 |1986-06-26T00:00:00.000Z |268728049
+;
+
+MultiTypedFieldsRenameKeep
+required_capability: implicit_casting_union_typed_numeric_and_date
+
+from employees, employees_incompatible
+| RENAME emp_no as new_emp_no, languages as new_languages, hire_date as new_hire_date, avg_worked_seconds as new_avg_worked_seconds
+| KEEP new_emp_no, new_languages, new_hire_date, new_avg_worked_seconds
+| sort new_emp_no, new_hire_date
+| limit 2
+;
+
+new_emp_no:long |new_languages:integer |new_hire_date:date_nanos |new_avg_worked_seconds:unsigned_long
+10001           |2                     |1986-06-26T00:00:00.000Z |268728049
+10001           |2                     |1986-06-26T00:00:00.000Z |268728049
+;
+
+MultiTypedFieldsEvalKeepSort
+required_capability: implicit_casting_union_typed_numeric_and_date
+
+FROM employees, employees_incompatible
+| DROP birth_date
+| EVAL x = emp_no + 1, y = hire_date + 1 year, z = hire_date::datetime
+| KEEP emp_no, x, hire_date, y, z
+| SORT emp_no, hire_date
+| limit 2
+;
+
+emp_no:long |x:long |hire_date:date_nanos     |y:date_nanos             |z:date
+10001       |10002  |1986-06-26T00:00:00.000Z |1987-06-26T00:00:00.000Z |1986-06-26T00:00:00.000Z
+10001       |10002  |1986-06-26T00:00:00.000Z |1987-06-26T00:00:00.000Z |1986-06-26T00:00:00.000Z
+;
+
+MultiTypedFieldsEvalFilterKeepSort
+required_capability: implicit_casting_union_typed_numeric_and_date
+
+FROM employees, employees_incompatible
+| EVAL x = emp_no + 1, y = hire_date + 1 day
+| WHERE emp_no > 10010 AND hire_date > "1992-01-01" AND languages < 3 AND height > 1.2
+| KEEP emp_no, hire_date
+| SORT emp_no, hire_date
+| limit 4
+;
+
+emp_no:long |hire_date:date_nanos
+10016       | 1995-01-27T00:00:00.000Z
+10016       | 1995-01-27T00:00:00.000Z
+10017       | 1993-08-03T00:00:00.000Z
+10017       | 1993-08-03T00:00:00.000Z
+;

x-pack/plugin/esql/qa/testFixtures/src/main/resources/union_types.csv-spec

@@ -850,7 +850,12 @@ public enum Cap {
         /**
          * Allow mixed numeric types in conditional functions - case, greatest and least
          */
-        MIXED_NUMERIC_TYPES_IN_CASE_GREATEST_LEAST;
+        MIXED_NUMERIC_TYPES_IN_CASE_GREATEST_LEAST,
+
+        /**
+         * Support implicit casting for union typed numeric and date/date_nanos fields
+         */
+        IMPLICIT_CASTING_UNION_TYPED_NUMERIC_AND_DATE;
 
         private final boolean enabled;
 

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/action/EsqlCapabilities.java

@@ -17,7 +17,6 @@
 import org.elasticsearch.xpack.esql.core.capabilities.Unresolvable;
 import org.elasticsearch.xpack.esql.core.expression.Alias;
 import org.elasticsearch.xpack.esql.core.expression.Expression;
-import org.elasticsearch.xpack.esql.core.expression.NamedExpression;
 import org.elasticsearch.xpack.esql.core.expression.TypeResolutions;
 import org.elasticsearch.xpack.esql.core.expression.function.Function;
 import org.elasticsearch.xpack.esql.core.expression.predicate.BinaryOperator;
@@ -36,7 +35,6 @@
 import org.elasticsearch.xpack.esql.plan.logical.LogicalPlan;
 import org.elasticsearch.xpack.esql.plan.logical.Lookup;
 import org.elasticsearch.xpack.esql.plan.logical.Project;
-import org.elasticsearch.xpack.esql.plan.logical.local.EsqlProject;
 import org.elasticsearch.xpack.esql.telemetry.FeatureMetric;
 import org.elasticsearch.xpack.esql.telemetry.Metrics;
 
@@ -96,16 +94,6 @@ Collection<Failure> verify(LogicalPlan plan, BitSet partialMetrics) {
                 return;
             }
 
-            if (p instanceof EsqlProject proj) {
-                for (NamedExpression projection : proj.projections()) {
-                    // don't call dataType() - it will fail on UnresolvedAttribute
-                    String className = String.valueOf(projection.getClass());
-                    if (projection.resolved() == false && projection instanceof UnsupportedAttribute == false) {
-
-                    }
-                }
-            }
-
             planCheckers.forEach(c -> c.accept(p, failures));
 
             checkOperationsOnUnsignedLong(p, failures);

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/analysis/Analyzer.java

@@ -97,7 +97,7 @@ public void testCommonTypeDateTimeIntervals() {
                     assertEqualsCommonType(dataType1, NULL, dataType1);
                 } else if (isDateTimeOrNanosOrTemporal(dataType2)) {
                     if ((dataType1 == DATE_NANOS && dataType2 == DATETIME) || (dataType1 == DATETIME && dataType2 == DATE_NANOS)) {
-                        assertNullCommonType(dataType1, dataType2);
+                        assertEqualsCommonType(dataType1, dataType2, DATE_NANOS);
                     } else if (isDateTime(dataType1) || isDateTime(dataType2)) {
                         assertEqualsCommonType(dataType1, dataType2, DATETIME);
                     } else if (dataType1 == DATE_NANOS || dataType2 == DATE_NANOS) {