From 42208bf4e7ec38a6f0c35a15bb0b173a9a6e9177 Mon Sep 17 00:00:00 2001
From: Eunbin Son <thswlsqls@naver.com>
Date: Thu, 29 Oct 2026 20:25:17 +0900
Subject: [PATCH] [core] Validate DATE partitions by their date value in
 partition.timestamp-format.strict

PartitionTimestampValidator passed DATE partition values to
PartitionTimeExtractor as raw epoch-day integers, so the documented
'yyyy-MM-dd' + '$dt' setup failed on every write once
partition.timestamp-format.strict was enabled. Convert DATE values to
LocalDate first, as PartitionExpireStrategy#convertPartition does.

Generated-by: Claude Code
---
 .../operation/AbstractFileStoreWrite.java     | 10 ++++
 .../paimon/table/sink/TableWriteTest.java     | 46 +++++++++++++++++++
 2 files changed, 56 insertions(+)

diff --git a/paimon-core/src/main/java/org/apache/paimon/operation/AbstractFileStoreWrite.java b/paimon-core/src/main/java/org/apache/paimon/operation/AbstractFileStoreWrite.java
index 0c0738c6173e..ba9b4223e91f 100644
--- a/paimon-core/src/main/java/org/apache/paimon/operation/AbstractFileStoreWrite.java
+++ b/paimon-core/src/main/java/org/apache/paimon/operation/AbstractFileStoreWrite.java
@@ -40,6 +40,7 @@
 import org.apache.paimon.partition.PartitionTimeExtractor;
 import org.apache.paimon.table.sink.CommitMessage;
 import org.apache.paimon.table.sink.CommitMessageImpl;
+import org.apache.paimon.types.DataTypeRoot;
 import org.apache.paimon.types.RowType;
 import org.apache.paimon.utils.CommitIncrement;
 import org.apache.paimon.utils.ExecutorThreadFactory;
@@ -53,6 +54,7 @@
 
 import javax.annotation.Nullable;
 
+import java.time.LocalDate;
 import java.time.format.DateTimeParseException;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -820,6 +822,14 @@ private static PartitionTimestampValidator create(
 
         private void validate(BinaryRow partition) {
             Object[] array = partitionConverter.convert(partition);
+            RowType partitionType = partitionConverter.rowType();
+            for (int i = 0; i < array.length; i++) {
+                // DATE is stored as an epoch day, same as PartitionExpireStrategy#convertPartition.
+                if (array[i] != null
+                        && partitionType.getTypeAt(i).getTypeRoot() == DataTypeRoot.DATE) {
+                    array[i] = LocalDate.ofEpochDay((Integer) array[i]);
+                }
+            }
             try {
                 timeExtractor.extract(partitionKeys, Arrays.asList(array));
             } catch (DateTimeParseException e) {
diff --git a/paimon-core/src/test/java/org/apache/paimon/table/sink/TableWriteTest.java b/paimon-core/src/test/java/org/apache/paimon/table/sink/TableWriteTest.java
index 3441dadecf89..aa4f0e10c266 100644
--- a/paimon-core/src/test/java/org/apache/paimon/table/sink/TableWriteTest.java
+++ b/paimon-core/src/test/java/org/apache/paimon/table/sink/TableWriteTest.java
@@ -52,6 +52,7 @@
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;
 
+import java.time.LocalDate;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
@@ -317,6 +318,51 @@ public void testPartitionTimestampValidation() throws Exception {
         write.close();
     }
 
+    @Test
+    public void testPartitionTimestampValidationWithDatePartition() throws Exception {
+        RowType rowType =
+                RowType.of(
+                        new DataType[] {
+                            DataTypes.DATE().notNull(),
+                            DataTypes.INT().notNull(),
+                            DataTypes.BIGINT()
+                        },
+                        new String[] {"dt", "k", "v"});
+        int dt = (int) LocalDate.of(2026, 10, 29).toEpochDay();
+
+        // valid partition value: 2026-10-29 matches yyyy-MM-dd
+        Options conf = new Options();
+        conf.set(CoreOptions.PARTITION_TIMESTAMP_FORMATTER, "yyyy-MM-dd");
+        conf.set(CoreOptions.PARTITION_TIMESTAMP_PATTERN, "$dt");
+        conf.set(CoreOptions.PARTITION_TIMESTAMP_FORMAT_STRICT, true);
+        FileStoreTable table =
+                createFileStoreTable(
+                        rowType, Collections.singletonList("dt"), Arrays.asList("dt", "k"), conf);
+        TableWriteImpl<?> write = table.newWrite(commitUser);
+        StreamTableCommit commit = table.newCommit(commitUser);
+        write.write(GenericRow.of(dt, 1, 1L));
+        commit.commit(0, write.prepareCommit(false, 0));
+        assertThat(readRows(table)).hasSize(1);
+        write.close();
+        commit.close();
+
+        // invalid partition value: 2026-10-29 does not match yyyyMMdd
+        Options mismatchConf = new Options();
+        mismatchConf.set(CoreOptions.PARTITION_TIMESTAMP_FORMATTER, "yyyyMMdd");
+        mismatchConf.set(CoreOptions.PARTITION_TIMESTAMP_FORMAT_STRICT, true);
+        FileStoreTable mismatchTable =
+                createFileStoreTable(
+                        rowType,
+                        Collections.singletonList("dt"),
+                        Arrays.asList("dt", "k"),
+                        mismatchConf);
+        TableWriteImpl<?> mismatchWrite = mismatchTable.newWrite(commitUser);
+        assertThatThrownBy(() -> mismatchWrite.write(GenericRow.of(dt, 1, 1L)))
+                .isInstanceOf(IllegalArgumentException.class)
+                .hasMessageContaining("dt=2026-10-29");
+        mismatchWrite.close();
+    }
+
     @Test
     public void testDeduplicateDeleteWithPrimaryKeyOnly() throws Exception {
         FileStoreTable table = createNotNullFileStoreTable(new Options());