HADOOP-11878. FileContext#fixRelativePart should check for not null for a more informative exception. (Brahma Reddy Battula via kasha)

(cherry picked from commit 2e3d83f97b85c015f16f1c162b8ef0e7fee1ddf2)

hadoop-common-project/hadoop-common/CHANGES.txt

@@ -221,6 +221,9 @@ Release 2.8.0 - UNRELEASED
     HADOOP-12194. Support for incremental generation in the protoc plugin.
     (wang)
 
+    HADOOP-11878. FileContext#fixRelativePart should check for not null for a
+    more informative exception. (Brahma Reddy Battula via kasha)
+
   BUG FIXES
 
     HADOOP-11802: DomainSocketWatcher thread terminates sometimes after there

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FileContext.java

@@ -59,6 +59,8 @@ import org.apache.hadoop.security.UserGroupInformation;
 import org.apache.hadoop.security.token.Token;
 import org.apache.hadoop.util.ShutdownHookManager;
 
+import com.google.common.base.Preconditions;
+
 /**
  * The FileContext class provides an interface to the application writer for
  * using the Hadoop file system.
@@ -272,6 +274,7 @@ public class FileContext {
    * has been deliberately declared private.
    */
   Path fixRelativePart(Path p) {
+    Preconditions.checkNotNull(p, "path cannot be null");
     if (p.isUriPathAbsolute()) {
       return p;
     } else {