[SPARK-21457][SQL] ExternalCatalog.listPartitions should correctly handle partition values with dot

## What changes were proposed in this pull request?

When we list partitions from hive metastore with a partial partition spec, we are expecting exact matching according to the partition values. However, hive treats dot specially and match any single character for dot. We should do an extra filter to drop unexpected partitions.

## How was this patch tested?

new regression test.

Author: Wenchen Fan <wenchen@databricks.com>

Closes #18671 from cloud-fan/hive.

(cherry picked from commit f18b905)
Signed-off-by: gatorsmile <gatorsmile@gmail.com>

Author: cloud-fan

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/catalog/ExternalCatalogUtils.scala

@@ -159,6 +159,18 @@ object ExternalCatalogUtils {
       }
     }
   }
+
+  /**
+   * Returns true if `spec1` is a partial partition spec w.r.t. `spec2`, e.g. PARTITION (a=1) is a
+   * partial partition spec w.r.t. PARTITION (a=1,b=2).
+   */
+  def isPartialPartitionSpec(
+      spec1: TablePartitionSpec,
+      spec2: TablePartitionSpec): Boolean = {
+    spec1.forall {
+      case (partitionColumn, value) => spec2(partitionColumn) == value
+    }
+  }
 }
 
 object CatalogUtils {

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/catalog/InMemoryCatalog.scala

@@ -542,18 +542,6 @@ class InMemoryCatalog(
     }
   }
 
-  /**
-   * Returns true if `spec1` is a partial partition spec w.r.t. `spec2`, e.g. PARTITION (a=1) is a
-   * partial partition spec w.r.t. PARTITION (a=1,b=2).
-   */
-  private def isPartialPartitionSpec(
-      spec1: TablePartitionSpec,
-      spec2: TablePartitionSpec): Boolean = {
-    spec1.forall {
-      case (partitionColumn, value) => spec2(partitionColumn) == value
-    }
-  }
-
   override def listPartitionsByFilter(
       db: String,
       table: String,

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/catalog/ExternalCatalogSuite.scala

@@ -439,6 +439,18 @@ abstract class ExternalCatalogSuite extends SparkFunSuite with BeforeAndAfterEac
     assert(catalog.listPartitions("db2", "tbl2", Some(Map("a" -> "unknown"))).isEmpty)
   }
 
+  test("SPARK-21457: list partitions with special chars") {
+    val catalog = newBasicCatalog()
+    assert(catalog.listPartitions("db2", "tbl1").isEmpty)
+
+    val part1 = CatalogTablePartition(Map("a" -> "1", "b" -> "i+j"), storageFormat)
+    val part2 = CatalogTablePartition(Map("a" -> "1", "b" -> "i.j"), storageFormat)
+    catalog.createPartitions("db2", "tbl1", Seq(part1, part2), ignoreIfExists = false)
+
+    assert(catalog.listPartitions("db2", "tbl1", Some(part1.spec)).map(_.spec) == Seq(part1.spec))
+    assert(catalog.listPartitions("db2", "tbl1", Some(part2.spec)).map(_.spec) == Seq(part2.spec))
+  }
+
   test("list partitions by filter") {
     val tz = TimeZone.getDefault.getID
     val catalog = newBasicCatalog()

sql/hive/src/main/scala/org/apache/spark/sql/hive/HiveExternalCatalog.scala

@@ -1074,9 +1074,19 @@ private[spark] class HiveExternalCatalog(conf: SparkConf, hadoopConf: Configurat
       table: String,
       partialSpec: Option[TablePartitionSpec] = None): Seq[CatalogTablePartition] = withClient {
     val partColNameMap = buildLowerCasePartColNameMap(getTable(db, table))
-    client.getPartitions(db, table, partialSpec.map(lowerCasePartitionSpec)).map { part =>
+    val res = client.getPartitions(db, table, partialSpec.map(lowerCasePartitionSpec)).map { part =>
       part.copy(spec = restorePartitionSpec(part.spec, partColNameMap))
     }
+
+    partialSpec match {
+      // This might be a bug of Hive: When the partition value inside the partial partition spec
+      // contains dot, and we ask Hive to list partitions w.r.t. the partial partition spec, Hive
+      // treats dot as matching any single character and may return more partitions than we
+      // expected. Here we do an extra filter to drop unexpected partitions.
+      case Some(spec) if spec.exists(_._2.contains(".")) =>
+        res.filter(p => isPartialPartitionSpec(spec, p.spec))
+      case _ => res
+    }
   }
 
   override def listPartitionsByFilter(