[HADOOP-12362] Set hadoop.tmp.dir and hadoop.log.dir in pom

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.7.1
• Fix Version/s: 2.8.0, 3.0.0-alpha1
• Target Version/s: 2.8.0
• Assignee: Charlie Helin
• Reporter: Charlie Helin
• Created: 18/Aug/15 19:38
• Updated: 30/Aug/16 01:23
• Resolved: 27/Aug/15 17:18

Description

There are some compelling features in later version of surefire which lets one exclude/include tests based the content of a file, re-running of test case etc.

However introduced in Surefire 2.18 is also https://issues.apache.org/jira/browse/SUREFIRE-649. Which changed the convention of null properties to empty string values (""). This only applies to forked tests such as the MapReduce tests and cause a couple of them to fail because of functionality that is directly or indirectly dependent on the value being null. One such example is Configuration.substituteVars() and TaskLog.getBaseLogDir().

substituteVars() shows the issue when the getProperty returns empty String, skipping the getRaw(var) expression. One way to work around this could be

 
   if (val == null || val.isEmpty()) {
        String raw = getRaw(var);
        if (raw != null) {
          // raw contains a value, otherwise default to whatever System.getProperty returned
          // since it could be an empty string
          val = raw;
        }
      }

getBaseLogDir, similarly when returns an empty string the schematics of java.io.File differs dependent on whether parent is null or "". A null value is interpreted as new File(file); whereas "" will be interpreted as new File(defaultParent /* / */, file);

This could simply be addressed with

  static String getBaseLogDir() {
    String logDir = System.getProperty("hadoop.log.dir");
    // there is a difference how null and "" is treated as a parent
    // directory when creating a file
    return logDir == null || logDir.isEmpty() ? null : logDir;
  }