(flink) branch master updated: [FLINK-38553][table-planner] CastRuleProvider should treat identity casts with highest precedence

[twalthr]

This is an automated email from the ASF dual-hosted git repository.

twalthr pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/flink.git


The following commit(s) were added to refs/heads/master by this push:
     new 5e4ae60590d [FLINK-38553][table-planner] CastRuleProvider should treat 
identity casts with highest precedence
5e4ae60590d is described below

commit 5e4ae60590df83df8c35d5fbc0a3584dd1623372
Author: Timo Walther <twal...@apache.org>
AuthorDate: Thu Oct 23 23:43:14 2025 +0200

    [FLINK-38553][table-planner] CastRuleProvider should treat identity casts 
with highest precedence
    
    This closes #27142.
---
 .../table/planner/functions/casting/CastRuleProvider.java   |  5 +++--
 .../planner/functions/casting/CastRuleProviderTest.java     | 13 +++++++++++++
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git 
a/flink-table/flink-table-planner/src/main/java/org/apache/flink/table/planner/functions/casting/CastRuleProvider.java
 
b/flink-table/flink-table-planner/src/main/java/org/apache/flink/table/planner/functions/casting/CastRuleProvider.java
index b3f879a8aaf..b1a050cd744 100644
--- 
a/flink-table/flink-table-planner/src/main/java/org/apache/flink/table/planner/functions/casting/CastRuleProvider.java
+++ 
b/flink-table/flink-table-planner/src/main/java/org/apache/flink/table/planner/functions/casting/CastRuleProvider.java
@@ -48,6 +48,8 @@ public class CastRuleProvider {
 
     static {
         INSTANCE
+                // Highest precedence rule
+                .addRule(IdentityCastRule.INSTANCE)
                 // Numeric rules
                 .addRule(DecimalToDecimalCastRule.INSTANCE)
                 .addRule(NumericPrimitiveToDecimalCastRule.INSTANCE)
@@ -96,8 +98,7 @@ public class CastRuleProvider {
                 .addRule(VariantToStringCastRule.INSTANCE)
                 // Special rules
                 .addRule(CharVarCharTrimPadCastRule.INSTANCE)
-                .addRule(NullToStringCastRule.INSTANCE)
-                .addRule(IdentityCastRule.INSTANCE);
+                .addRule(NullToStringCastRule.INSTANCE);
     }
 
     /* ------- Entrypoint ------- */
diff --git 
a/flink-table/flink-table-planner/src/test/java/org/apache/flink/table/planner/functions/casting/CastRuleProviderTest.java
 
b/flink-table/flink-table-planner/src/test/java/org/apache/flink/table/planner/functions/casting/CastRuleProviderTest.java
index af4b63d9ce6..4e230667111 100644
--- 
a/flink-table/flink-table-planner/src/test/java/org/apache/flink/table/planner/functions/casting/CastRuleProviderTest.java
+++ 
b/flink-table/flink-table-planner/src/test/java/org/apache/flink/table/planner/functions/casting/CastRuleProviderTest.java
@@ -28,9 +28,11 @@ import org.apache.flink.table.types.logical.VarCharType;
 import org.junit.jupiter.api.Test;
 
 import static org.apache.flink.table.api.DataTypes.BIGINT;
+import static org.apache.flink.table.api.DataTypes.FIELD;
 import static org.apache.flink.table.api.DataTypes.INT;
 import static org.apache.flink.table.api.DataTypes.ROW;
 import static org.apache.flink.table.api.DataTypes.STRING;
+import static org.apache.flink.table.api.DataTypes.STRUCTURED;
 import static org.apache.flink.table.api.DataTypes.TIME;
 import static org.apache.flink.table.api.DataTypes.TINYINT;
 import static org.apache.flink.table.types.logical.VarCharType.STRING_TYPE;
@@ -46,6 +48,10 @@ class CastRuleProviderTest {
                     .build();
     private static final LogicalType INT = INT().getLogicalType();
     private static final LogicalType TINYINT = TINYINT().getLogicalType();
+    private static final LogicalType ROW =
+            ROW(FIELD("a", INT()), FIELD("b", 
TINYINT().notNull())).getLogicalType();
+    private static final LogicalType STRUCTURED =
+            STRUCTURED("Obj", FIELD("a", INT()), FIELD("b", 
TINYINT().notNull())).getLogicalType();
 
     @Test
     void testResolveDistinctTypeToIdentityCastRule() {
@@ -55,6 +61,13 @@ class CastRuleProviderTest {
                 .isSameAs(IdentityCastRule.INSTANCE);
     }
 
+    @Test
+    void testResolveCompatiblesTypesToIdentityCastRule() {
+        assertThat(CastRuleProvider.resolve(INT, 
INT)).isSameAs(IdentityCastRule.INSTANCE);
+        assertThat(CastRuleProvider.resolve(ROW, 
ROW)).isSameAs(IdentityCastRule.INSTANCE);
+        assertThat(CastRuleProvider.resolve(ROW, 
STRUCTURED)).isSameAs(IdentityCastRule.INSTANCE);
+    }
+
     @Test
     void testResolveIntToBigIntWithDistinct() {
         assertThat(CastRuleProvider.resolve(INT, DISTINCT_BIG_INT))