Merge pull request apache#371 from palantir/jt/fix-case-sensitive-literals

[SPARK-24151] fix case sensitive literals

Author: jamesthomp

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/Analyzer.scala

@@ -981,7 +981,7 @@ class Analyzer(
     // support CURRENT_DATE and CURRENT_TIMESTAMP
     val literalFunctions = Seq(CurrentDate(), CurrentTimestamp())
     val name = nameParts.head
-    val func = literalFunctions.find(e => resolver(e.prettyName, name))
+    val func = literalFunctions.find(e => caseInsensitiveResolution(e.prettyName, name))
     func.map(wrapper)
   }
 

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

@@ -631,6 +631,14 @@ class SQLQuerySuite extends QueryTest with SharedSQLContext {
     }
   }
 
+  test("current_date with case sensitive") {
+    withSQLConf(SQLConf.CASE_SENSITIVE.key -> "true") {
+      checkAnswer(
+        sql("SELECT DATEDIFF(CURRENT_DATE, current_date)"),
+        Row(0))
+    }
+  }
+
   test("inner join where, one match per row") {
     withSQLConf(SQLConf.CASE_SENSITIVE.key -> "true") {
       checkAnswer(