YARN-3768. ArrayIndexOutOfBoundsException with empty environment variables. (Zhihai Xu via gera)

(cherry picked from commit 6f2a41e37d0b36cdafcfff75125165f212c612a6)

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/Shell.java

@@ -221,10 +221,12 @@ abstract public class Shell {
       new String[] { "kill", "-" + code, isSetsidAvailable ? "-" + pid : pid };
   }
 
+  public static final String ENV_NAME_REGEX = "[A-Za-z_][A-Za-z0-9_]*";
   /** Return a regular expression string that match environment variables */
   public static String getEnvironmentVariableRegex() {
-    return (WINDOWS) ? "%([A-Za-z_][A-Za-z0-9_]*?)%" :
-      "\\$([A-Za-z_][A-Za-z0-9_]*)";
+    return (WINDOWS)
+        ? "%(" + ENV_NAME_REGEX + "?)%"
+        : "\\$(" + ENV_NAME_REGEX + ")";
   }
   
   /**

hadoop-yarn-project/CHANGES.txt

@@ -526,6 +526,9 @@ Release 2.8.0 - UNRELEASED
     YARN-3770. SerializedException should also handle java.lang.Error on
     de-serialization. (Lavkesh Lahngir via jianhe)
 
+    YARN-3768. ArrayIndexOutOfBoundsException with empty environment variables.
+    (Zhihai Xu via gera)
+
 Release 2.7.2 - UNRELEASED
 
   INCOMPATIBLE CHANGES

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/util/Apps.java

@@ -44,6 +44,14 @@ import org.apache.hadoop.yarn.exceptions.YarnRuntimeException;
 public class Apps {
   public static final String APP = "application";
   public static final String ID = "ID";
+  private static final Pattern VAR_SUBBER =
+      Pattern.compile(Shell.getEnvironmentVariableRegex());
+  private static final Pattern VARVAL_SPLITTER = Pattern.compile(
+        "(?<=^|,)"                            // preceded by ',' or line begin
+      + '(' + Shell.ENV_NAME_REGEX + ')'      // var group
+      + '='
+      + "([^,]*)"                             // val group
+      );
 
   public static ApplicationId toAppID(String aid) {
     Iterator<String> it = _split(aid).iterator();
@@ -73,11 +81,10 @@ public class Apps {
   public static void setEnvFromInputString(Map<String, String> env,
       String envString,  String classPathSeparator) {
     if (envString != null && envString.length() > 0) {
-      String childEnvs[] = envString.split(",");
-      Pattern p = Pattern.compile(Shell.getEnvironmentVariableRegex());
-      for (String cEnv : childEnvs) {
-        String[] parts = cEnv.split("="); // split on '='
-        Matcher m = p.matcher(parts[1]);
+      Matcher varValMatcher = VARVAL_SPLITTER.matcher(envString);
+      while (varValMatcher.find()) {
+        String envVar = varValMatcher.group(1);
+        Matcher m = VAR_SUBBER.matcher(varValMatcher.group(2));
         StringBuffer sb = new StringBuffer();
         while (m.find()) {
           String var = m.group(1);
@@ -93,7 +100,7 @@ public class Apps {
           m.appendReplacement(sb, Matcher.quoteReplacement(replace));
         }
         m.appendTail(sb);
-        addToEnvironment(env, parts[0], sb.toString(), classPathSeparator);
+        addToEnvironment(env, envVar, sb.toString(), classPathSeparator);
       }
     }
   }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/test/java/org/apache/hadoop/yarn/util/TestApps.java

@@ -0,0 +1,61 @@
+/**
+* Licensed to the Apache Software Foundation (ASF) under one
+* or more contributor license agreements.  See the NOTICE file
+* distributed with this work for additional information
+* regarding copyright ownership.  The ASF licenses this file
+* to you under the Apache License, Version 2.0 (the
+* "License"); you may not use this file except in compliance
+* with the License.  You may obtain a copy of the License at
+*
+*     http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+package org.apache.hadoop.yarn.util;
+
+import org.apache.hadoop.util.Shell;
+import org.junit.Test;
+
+import java.io.File;
+import java.util.HashMap;
+import java.util.Map;
+
+import static org.junit.Assert.assertEquals;
+
+public class TestApps {
+  @Test
+  public void testSetEnvFromInputString() {
+    Map<String, String> environment = new HashMap<String, String>();
+    environment.put("JAVA_HOME", "/path/jdk");
+    String goodEnv = "a1=1,b_2=2,_c=3,d=4,e=,f_win=%JAVA_HOME%"
+        + ",g_nix=$JAVA_HOME";
+    Apps.setEnvFromInputString(environment, goodEnv, File.pathSeparator);
+    assertEquals("1", environment.get("a1"));
+    assertEquals("2", environment.get("b_2"));
+    assertEquals("3", environment.get("_c"));
+    assertEquals("4", environment.get("d"));
+    assertEquals("", environment.get("e"));
+    if (Shell.WINDOWS) {
+      assertEquals("$JAVA_HOME", environment.get("g_nix"));
+      assertEquals("/path/jdk", environment.get("f_win"));
+    } else {
+      assertEquals("/path/jdk", environment.get("g_nix"));
+      assertEquals("%JAVA_HOME%", environment.get("f_win"));
+    }
+    String badEnv = "1,,2=a=b,3=a=,4==,5==a,==,c-3=3,=";
+    environment.clear();
+    Apps.setEnvFromInputString(environment, badEnv, File.pathSeparator);
+    assertEquals(environment.size(), 0);
+
+    // Test "=" in the value part
+    environment.clear();
+    Apps.setEnvFromInputString(environment, "b1,e1==,e2=a1=a2,b2",
+        File.pathSeparator);
+    assertEquals("=", environment.get("e1"));
+    assertEquals("a1=a2", environment.get("e2"));
+  }
+}