Fail

Description

Exits the current build (just throwing a BuildException), optionally printing additional information.

The message of the Exception can be set via the message attribute or character data nested into the element.

Parameters

Attribute Description Required
message A message giving further information on why the build exited No
if Only fail if a property of the given name exists in the current project No
unless Only fail if a property of the given name doesn't exist in the current project No
status Exit using the specified status code; assuming the generated Exception is not caught, the JVM will exit with this status. Since Ant 1.6.2 No

Parameters specified as nested elements

As an alternative to the if/unless attributes, conditional failure can be achieved using a single nested <condition> element, which should contain exactly one core or custom condition. For information about conditions, see here.
Since Ant 1.6.2

Examples

  <fail/>

will exit the current build with no further information given.

BUILD FAILED

build.xml:4: No message

  <fail message="Something wrong here."/>

will exit the current build and print something like the following to wherever your output goes: 

BUILD FAILED

build.xml:4: Something wrong here.

  <fail>Something wrong here.</fail>

will give the same result as above.

  <fail unless="thisdoesnotexist"/>

will exit the current build and print something like the following to wherever your output goes: 

BUILD FAILED

build.xml:2: unless=thisdoesnotexist
Using a condition to achieve the same effect: 
  <fail>
     <condition>
       <not>
         <isset property="thisdoesnotexist"/>
       </not>
     </condition>
   </fail>

Output:

BUILD FAILED

build.xml:2: condition satisfied