From 9d3a92b963271897565cfd81098050b702fcdac5 Mon Sep 17 00:00:00 2001
From: Vitalii Diravka <vitalii.diravka@gmail.com>
Date: Tue, 26 Sep 2017 04:06:45 -0700
Subject: [PATCH] DRILL-5792: CONVERT_FROM_JSON on an empty file throws runtime
 exception

---
 .../src/main/codegen/templates/TypeHelper.java        |  1 +
 exec/jdbc/pom.xml                                     |  1 +
 .../org/apache/drill/jdbc/test/TestJdbcQuery.java     | 11 +++++++++--
 exec/jdbc/src/test/resources/empty.csv                |  0
 4 files changed, 11 insertions(+), 2 deletions(-)
 create mode 100644 exec/jdbc/src/test/resources/empty.csv

diff --git a/exec/java-exec/src/main/codegen/templates/TypeHelper.java b/exec/java-exec/src/main/codegen/templates/TypeHelper.java
index 5ccda852303..e4c8f33193a 100644
--- a/exec/java-exec/src/main/codegen/templates/TypeHelper.java
+++ b/exec/java-exec/src/main/codegen/templates/TypeHelper.java
@@ -61,6 +61,7 @@ public static SqlAccessor getSqlAccessor(ValueVector vector){
     </#list>
     case MAP:
     case LIST:
+    case NULL:
       return new GenericAccessor(vector);
     }
     throw new UnsupportedOperationException(buildErrorMessage("find sql accessor", type));
diff --git a/exec/jdbc/pom.xml b/exec/jdbc/pom.xml
index c3c48fa5500..71862f6b206 100644
--- a/exec/jdbc/pom.xml
+++ b/exec/jdbc/pom.xml
@@ -119,6 +119,7 @@
             <exclude>**/.checkstyle</exclude>
             <exclude>**/.buildpath</exclude>
             <exclude>**/*.json</exclude>
+            <exclude>**/*.csv</exclude>
             <exclude>**/*.iml</exclude>
             <exclude>**/git.properties</exclude>
             <exclude>**/donuts-output-data.txt</exclude>
diff --git a/exec/jdbc/src/test/java/org/apache/drill/jdbc/test/TestJdbcQuery.java b/exec/jdbc/src/test/java/org/apache/drill/jdbc/test/TestJdbcQuery.java
index 1dd172f41b9..894e06f037e 100644
--- a/exec/jdbc/src/test/java/org/apache/drill/jdbc/test/TestJdbcQuery.java
+++ b/exec/jdbc/src/test/java/org/apache/drill/jdbc/test/TestJdbcQuery.java
@@ -370,7 +370,7 @@ public void testTimeIntervalAddOverflow() throws Exception {
 
   @Test // DRILL-1051
   public void testOldDateTimeJulianCalendar() throws Exception {
-    // Should be work with any timezone
+    // Should work with any timezone
     JdbcAssert.withNoDefaultSchema()
         .sql("select cast(to_timestamp('1581-12-01 23:32:01', 'yyyy-MM-dd HH:mm:ss') as date) as `DATE`, " +
             "to_timestamp('1581-12-01 23:32:01', 'yyyy-MM-dd HH:mm:ss') as `TIMESTAMP`, " +
@@ -381,7 +381,7 @@ public void testOldDateTimeJulianCalendar() throws Exception {
 
   @Test // DRILL-1051
   public void testOldDateTimeLocalMeanTime() throws Exception {
-    // Should be work with any timezone
+    // Should work with any timezone
     JdbcAssert.withNoDefaultSchema()
         .sql("select cast(to_timestamp('1883-11-16 01:32:01', 'yyyy-MM-dd HH:mm:ss') as date) as `DATE`, " +
             "to_timestamp('1883-11-16 01:32:01', 'yyyy-MM-dd HH:mm:ss') as `TIMESTAMP`, " +
@@ -390,4 +390,11 @@ public void testOldDateTimeLocalMeanTime() throws Exception {
         .returns("DATE=1883-11-16; TIMESTAMP=1883-11-16 01:32:01.0; TIME=01:32:01");
   }
 
+  @Test // DRILL-5792
+  public void testConvertFromInEmptyInputSql() throws Exception {
+    JdbcAssert.withNoDefaultSchema()
+        .sql("SELECT CONVERT_FROM(columns[1], 'JSON') as col1 from cp.`empty.csv`")
+        .returns("");
+  }
+
 }
diff --git a/exec/jdbc/src/test/resources/empty.csv b/exec/jdbc/src/test/resources/empty.csv
new file mode 100644
index 00000000000..e69de29bb2d