[SPARK-29873][SQL][Test][FOLLOWUP] set operations should not escape when regen golden file with --SET --import both specified

sql/core/src/test/resources/sql-tests/inputs/ansi/higher-order-functions.sql

@@ -1 +1 @@
---import higher-order-functions.sql
+--IMPORT higher-order-functions.sql

sql/core/src/test/resources/sql-tests/inputs/ansi/interval.sql

@@ -1,4 +1,4 @@
---import interval.sql
+--IMPORT interval.sql
 
 -- the `interval` keyword can be omitted with ansi mode
 select 1 year 2 days;

sql/core/src/test/resources/sql-tests/inputs/ansi/literals.sql

@@ -1,2 +1,2 @@
 --- malformed interval literal with ansi mode
---import literals.sql
+--IMPORT literals.sql

sql/core/src/test/resources/sql-tests/inputs/interval-display-iso_8601.sql

@@ -1,3 +1,3 @@
 -- tests for interval output style with iso_8601 format
 --SET spark.sql.intervalOutputStyle = ISO_8601
---import interval-display.sql
+--IMPORT interval-display.sql

sql/core/src/test/resources/sql-tests/inputs/interval-display-sql_standard.sql

@@ -1,3 +1,3 @@
 -- tests for interval output style with sql standard format
 --SET spark.sql.intervalOutputStyle = SQL_STANDARD
---import interval-display.sql
+--IMPORT interval-display.sql

sql/core/src/test/scala/org/apache/spark/sql/SQLQueryTestSuite.scala

@@ -65,7 +65,7 @@ import org.apache.spark.tags.ExtendedSQLTest
  *  1. A list of SQL queries separated by semicolon.
  *  2. Lines starting with -- are treated as comments and ignored.
  *  3. Lines starting with --SET are used to run the file with the following set of configs.
- *  4. Lines starting with --import are used to load queries from another test file.
+ *  4. Lines starting with --IMPORT are used to load queries from another test file.
  *
  * For example:
  * {{{
@@ -265,9 +265,9 @@ class SQLQueryTestSuite extends QueryTest with SharedSparkSession {
 
     val (comments, code) = input.split("\n").partition(_.trim.startsWith("--"))
 
-    // If `--import` found, load code from another test case file, then insert them
+    // If `--IMPORT` found, load code from another test case file, then insert them
     // into the head in this test.
-    val importedTestCaseName = comments.filter(_.startsWith("--import ")).map(_.substring(9))
+    val importedTestCaseName = comments.filter(_.startsWith("--IMPORT ")).map(_.substring(9))
     val importedCode = importedTestCaseName.flatMap { testCaseName =>
       listTestCases.find(_.name == testCaseName).map { testCase =>
         val input = fileToString(new File(testCase.inputFile))
@@ -283,13 +283,17 @@ class SQLQueryTestSuite extends QueryTest with SharedSparkSession {
       // Fix misplacement when comment is at the end of the query.
       .map(_.split("\n").filterNot(_.startsWith("--")).mkString("\n")).map(_.trim).filter(_ != "")
 
-    // When we are regenerating the golden files, we don't need to set any config as they
-    // all need to return the same result
-    if (regenerateGoldenFiles || !isTestWithConfigSets) {
+    // When we are regenerating the golden files for test cases without '--IMPORT' specified, or
+    // running test cases against [[ThriftServerQueryTestSuite], we don't need to set any config as
+    // they all need to return the same result.
+    // When we use '--SET' and '--IMPORT' together for those import queries, we want to run the
+    // same queries from the original file but with different settings and save the answers. So the
+    // `--SET` will be respected in this case.
+    if ((regenerateGoldenFiles && importedTestCaseName.isEmpty) || !isTestWithConfigSets) {
       runQueries(queries, testCase, None)
     } else {
       val configSets = {
-        val configLines = comments.filter(_.startsWith("--SET")).map(_.substring(5))
+        val configLines = comments.filter(_.startsWith("--SET ")).map(_.substring(6))
         val configs = configLines.map(_.split(",").map { confAndValue =>
           val (conf, value) = confAndValue.span(_ != '=')
           conf.trim -> value.substring(1).trim