When I run ant from the command-line, if I get a failure, I get a non-zero exit status ($? on UNIX, %ERRORLEVEL% on Windows). But we have a Java program which is running ant (through ProcessBuilder), and when ant fails, on Windows we cannot get the exit status.
I just verified this with this simple ant test file:
<project name="x" default="a">
<target name="a">
<fail/>
</target>
</project>
On UNIX, running ant prints a failure message, and echoing $? afterward prints 1. On Windows, running ant or ant.bat prints a failure message, and echoing %ERRORLEVEL% afterward prints 1.
Now, using the test program below: On UNIX, java Run ant prints a failure message, and echoing $? afterward prints 1. On Windows, java Run ant can't find a program named ant to run, but java Run ant.bat prints a failure message, yet echoing %ERRORLEVEL% afterward prints 0. What gives?
We're relying on being able to check the exit status after running ant. We were, anyway. Why can't we rely on this, programmatically?
Test program:
import java.io.*;
public class Run {
public static void main(String[] args) throws IOException, InterruptedException {
ProcessBuilder pb = new ProcessBuilder(args);
Process p = pb.start();
ProcThread stdout = new ProcThread(p.getInputStream(), System.out);
ProcThread stderr = new ProcThread(p.getErrorStream(), System.err);
stdout.start();
stderr.start();
int errorLevel = p.waitFor();
stdout.join();
stderr.join();
IOException outE = stdout.getException();
if (outE != null)
throw(outE);
IOException errE = stdout.getException();
if (errE != null)
throw(errE);
System.exit(errorLevel);
}
static class ProcThread extends Thread {
BufferedReader input;
PrintStream out;
IOException ex;
ProcThread(InputStream is, PrintStream out) {
input = new BufferedReader(new InputStreamReader(is));
this.out = out;
}
@Override
public void run() {
String line;
try {
while ((line = input.readLine()) != null)
out.println(line);
} catch (IOException e) {
setException(e);
}
}
private void setException(IOException e) {
this.ex = e;
}
public IOException getException() {
return ex;
}
}
}