Program: 64243
Project: 64243
Buggy source:
/** 
 * Determines if the OS on which Ant is executing matches the given OS family, name, architecture and version
 * @param family   The OS family
 * @param name   The OS name
 * @param arch   The OS architecture
 * @param version   The OS version
 * @since 1.7
 */
public static boolean isOs(String family,String name,String arch,String version){
  boolean retValue=false;
  if (family != null || name != null || arch != null || version != null) {
    boolean isFamily=true;
    boolean isName=true;
    boolean isArch=true;
    boolean isVersion=true;
    if (family != null) {
      if (family.equals("String_Node_Str")) {
        isFamily=osName.indexOf("String_Node_Str") > -1;
      }
 else       if (family.equals("String_Node_Str")) {
        isFamily=osName.indexOf("String_Node_Str") > -1;
      }
 else       if (family.equals("String_Node_Str")) {
        isFamily=osName.indexOf("String_Node_Str") > -1;
      }
 else       if (family.equals("String_Node_Str")) {
        isFamily=pathSep.equals("String_Node_Str") && !isFamily("String_Node_Str");
      }
 else       if (family.equals("String_Node_Str")) {
        isFamily=osName.indexOf("String_Node_Str") > -1;
      }
 else       if (family.equals("String_Node_Str")) {
        isFamily=pathSep.equals("String_Node_Str") && (!isFamily("String_Node_Str") || osName.endsWith("String_Node_Str"));
      }
 else       if (family.equals("String_Node_Str")) {
        isFamily=isFamily("String_Node_Str") && !(osName.indexOf("String_Node_Str") >= 0 || osName.indexOf("String_Node_Str") >= 0 || osName.indexOf("String_Node_Str") >= 0);
      }
 else       if (family.equals("String_Node_Str")) {
        isFamily=osName.indexOf("String_Node_Str") > -1 || osName.indexOf("String_Node_Str") > -1;
      }
 else       if (family.equals("String_Node_Str")) {
        isFamily=osName.indexOf("String_Node_Str") > -1;
      }
 else {
        throw new BuildException("String_Node_Str" + family + "String_Node_Str");
      }
    }
    if (name != null) {
      isName=name.equals(osName);
    }
    if (arch != null) {
      isArch=arch.equals(osArch);
    }
    if (version != null) {
      isVersion=version.equals(osVersion);
    }
    retValue=isFamily && isName && isArch&& isVersion;
  }
  return retValue;
}

Fixed version (ground truth):
/** 
 * Determines if the OS on which Ant is executing matches the given OS family, name, architecture and version
 * @param family   The OS family
 * @param name   The OS name
 * @param arch   The OS architecture
 * @param version   The OS version
 * @since 1.7
 */
public static boolean isOs(String family,String name,String arch,String version){
  boolean retValue=false;
  if (family != null || name != null || arch != null || version != null) {
    boolean isFamily=true;
    boolean isName=true;
    boolean isArch=true;
    boolean isVersion=true;
    if (family != null) {
      if (family.equals("String_Node_Str")) {
        isFamily=osName.indexOf("String_Node_Str") > -1;
      }
 else       if (family.equals("String_Node_Str")) {
        isFamily=osName.indexOf("String_Node_Str") > -1;
      }
 else       if (family.equals("String_Node_Str")) {
        isFamily=osName.indexOf("String_Node_Str") > -1;
      }
 else       if (family.equals("String_Node_Str")) {
        isFamily=pathSep.equals("String_Node_Str") && !isFamily("String_Node_Str");
      }
 else       if (family.equals("String_Node_Str")) {
        isFamily=osName.indexOf("String_Node_Str") > -1;
      }
 else       if (family.equals("String_Node_Str")) {
        isFamily=pathSep.equals("String_Node_Str") && (!isFamily("String_Node_Str") || osName.endsWith("String_Node_Str"));
      }
 else       if (family.equals("String_Node_Str")) {
        isFamily=isFamily("String_Node_Str") && !(osName.indexOf("String_Node_Str") >= 0 || osName.indexOf("String_Node_Str") >= 0 || osName.indexOf("String_Node_Str") >= 0 || osName.indexOf("String_Node_Str") >= 0);
      }
 else       if (family.equals("String_Node_Str")) {
        isFamily=osName.indexOf("String_Node_Str") > -1 || osName.indexOf("String_Node_Str") > -1;
      }
 else       if (family.equals("String_Node_Str")) {
        isFamily=osName.indexOf("String_Node_Str") > -1;
      }
 else {
        throw new BuildException("String_Node_Str" + family + "String_Node_Str");
      }
    }
    if (name != null) {
      isName=name.equals(osName);
    }
    if (arch != null) {
      isArch=arch.equals(osArch);
    }
    if (version != null) {
      isVersion=version.equals(osVersion);
    }
    retValue=isFamily && isName && isArch&& isVersion;
  }
  return retValue;
}