Re: [PR] [SPARK-45748][SQL] Add a .fromSQL helper function for Literals [spark]

["cloud-fan (via GitHub)" <gi...@apache.org>]

cloud-fan commented on code in PR #43612:
URL: https://github.com/apache/spark/pull/43612#discussion_r1378356375


##########
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/literals.scala:
##########
@@ -247,6 +251,67 @@ object Literal {
       s"Literal must have a corresponding value to ${dataType.catalogString}, " +
       s"but class ${Utils.getSimpleName(value.getClass)} found.")
   }
+
+  /**
+   * Parse and analyze the .sql string of a Literal, construct the Literal given the data type json.
+   * Example usage:
+   *   val serializedValue = lit.sql
+   *   val dataTypeJson = lit.dataType.json
+   *   val deserializedLit: Literal = Literal.fromSQL(serializedValue, dataTypeJson)
+   *
+   * @param valueSqlStr the .sql string of the Literal
+   * @param dataTypeJson the json format data type of the Literal
+   * @throws AnalysisException INVALID_LITERAL_VALUE_SQL_STRING_FOR_DESERIALIZATION
+   */
+  private[sql] def fromSQL(valueSqlStr: String, dataTypeJson: String): Literal = {
+    def parseAndAnalyze(valueSqlStr: String, dataType: DataType): Expression = {
+      lazy val parser = new CatalystSqlParser()
+      val parsed: Expression = try {
+        parser.parseExpression(valueSqlStr)
+      } catch {
+        case e: Exception =>
+          throw QueryCompilationErrors.invalidLiteralValueSQLStringForDeserialization(
+            "PARSE_FAILURE", valueSqlStr, dataType, Some(e))
+      }
+
+      val analyzer: Analyzer = ResolveDefaultColumns.DefaultColumnAnalyzer
+      val analyzedPlan = try {
+        val analyzed = analyzer.execute(
+          Project(
+            Seq(Alias(Cast(parsed, dataType, evalMode = EvalMode.ANSI), "alias")()),
+            OneRowRelation()
+          )
+        )
+        analyzer.checkAnalysis(analyzed)
+        // if data type is un-castable it fails here
+        ConstantFolding(analyzed)
+      } catch {
+        case e: Exception =>
+          throw QueryCompilationErrors.invalidLiteralValueSQLStringForDeserialization(
+            "ANALYSIS_FAILURE", valueSqlStr, dataType, Some(e))
+      }
+      analyzedPlan.collectFirst { case Project(Seq(a: Alias), OneRowRelation()) => a.child }.get
+    }
+
+    val dataType = DataType.fromJson(dataTypeJson)
+    val analyzedExpr = if (dataType.sameType(CalendarIntervalType)) {

Review Comment:
   we should check if it contains `CalendarIntervalType`.



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