Fix blocking reads from System.in in command line execution

src/main/java/org/codehaus/plexus/util/cli/CommandLineUtils.java

@@ -146,13 +146,13 @@ public void run() {
 
             @Override
             public Integer call() throws CommandLineException {
-                StreamFeeder inputFeeder = null;
+                StreamPollFeeder inputFeeder = null;
                 StreamPumper outputPumper = null;
                 StreamPumper errorPumper = null;
                 boolean success = false;
                 try {
                     if (systemIn != null) {
-                        inputFeeder = new StreamFeeder(systemIn, p.getOutputStream());
+                        inputFeeder = new StreamPollFeeder(systemIn, p.getOutputStream());
                         inputFeeder.start();
                     }
 
@@ -288,11 +288,11 @@ private static void handleException(final StreamPumper streamPumper, final Strin
         }
     }
 
-    private static void handleException(final StreamFeeder streamFeeder, final String streamName)
+    private static void handleException(final StreamPollFeeder streamPollFeeder, final String streamName)
             throws CommandLineException {
-        if (streamFeeder.getException() != null) {
+        if (streamPollFeeder.getException() != null) {
             throw new CommandLineException(
-                    String.format("Failure processing %s.", streamName), streamFeeder.getException());
+                    String.format("Failure processing %s.", streamName), streamPollFeeder.getException());
         }
     }
 

src/main/java/org/codehaus/plexus/util/cli/StreamFeeder.java

@@ -24,8 +24,9 @@
  * Read from an InputStream and write the output to an OutputStream.
  *
  * @author <a href="mailto:trygvis@inamo.no">Trygve Laugst&oslash;l</a>
- *
+ * @deprecated Use {@link StreamPollFeeder} instead. This class can block when used with System.in
  */
+@Deprecated
 public class StreamFeeder extends AbstractStreamHandler {
 
     private InputStream input;

src/main/java/org/codehaus/plexus/util/cli/StreamPollFeeder.java

@@ -0,0 +1,133 @@
+package org.codehaus.plexus.util.cli;
+
+/*
+ * Copyright The Codehaus Foundation.
+ *
+ * Licensed 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.
+ */
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+
+/**
+ * Poll InputStream for available data and write the output to an OutputStream.
+ * <p>
+ * This class is designed to avoid blocking when reading from streams like System.in.
+ * It polls the input stream for available data instead of blocking on read operations.
+ *
+ * @author <a href="mailto:trygvis@inamo.no">Trygve Laugst&oslash;l</a>
+ */
+public class StreamPollFeeder extends AbstractStreamHandler {
+
+    public static final int BUF_LEN = 80;
+
+    private InputStream input;
+
+    private OutputStream output;
+
+    private volatile Throwable exception = null;
+
+    private final Object lock = new Object();
+
+    /**
+     * Create a new StreamPollFeeder
+     *
+     * @param input Stream to read from
+     * @param output Stream to write to
+     */
+    public StreamPollFeeder(InputStream input, OutputStream output) {
+        super();
+        this.input = input;
+        this.output = output;
+    }
+
+    @Override
+    public void run() {
+        byte[] buf = new byte[BUF_LEN];
+
+        try {
+            while (!isDone()) {
+                if (input.available() > 0) {
+                    int i = input.read(buf);
+                    if (i > 0) {
+                        output.write(buf, 0, i);
+                        output.flush();
+                    } else {
+                        setDone();
+                    }
+                } else {
+                    synchronized (lock) {
+                        if (!isDone()) {
+                            lock.wait(100);
+                        }
+                    }
+                }
+            }
+        } catch (IOException e) {
+            exception = e;
+        } catch (InterruptedException e) {
+            Thread.currentThread().interrupt();
+        } finally {
+            close();
+        }
+    }
+
+    public void close() {
+        if (input != null) {
+            synchronized (input) {
+                try {
+                    input.close();
+                } catch (IOException ex) {
+                    if (exception == null) {
+                        exception = ex;
+                    }
+                }
+
+                input = null;
+            }
+        }
+
+        if (output != null) {
+            synchronized (output) {
+                try {
+                    output.close();
+                } catch (IOException ex) {
+                    if (exception == null) {
+                        exception = ex;
+                    }
+                }
+
+                output = null;
+            }
+        }
+    }
+
+    /**
+     * @since 3.1.0
+     * @return the Exception
+     */
+    public Throwable getException() {
+        return exception;
+    }
+
+    @Override
+    public synchronized void waitUntilDone() throws InterruptedException {
+        synchronized (lock) {
+            setDone();
+            lock.notifyAll();
+        }
+
+        join();
+    }
+}

src/test/java/org/codehaus/plexus/util/cli/StreamPollFeederTest.java

@@ -0,0 +1,57 @@
+package org.codehaus.plexus.util.cli;
+
+/*
+ * Copyright The Codehaus Foundation.
+ *
+ * Licensed 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.
+ */
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+public class StreamPollFeederTest {
+
+    @Test
+    public void dataShouldBeCopied() throws InterruptedException, IOException {
+
+        StringBuilder TEST_DATA = new StringBuilder();
+        for (int i = 0; i < 100; i++) {
+            TEST_DATA.append("TestData");
+        }
+
+        ByteArrayInputStream inputStream =
+                new ByteArrayInputStream(TEST_DATA.toString().getBytes());
+        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+
+        StreamPollFeeder streamPollFeeder = new StreamPollFeeder(inputStream, outputStream);
+
+        streamPollFeeder.start();
+
+        //  wait until all data from steam will be read
+        while (outputStream.size() < TEST_DATA.length()) {
+            Thread.sleep(100);
+        }
+
+        // wait until process finish
+        streamPollFeeder.waitUntilDone();
+        assertNull(streamPollFeeder.getException());
+
+        assertEquals(TEST_DATA.toString(), outputStream.toString());
+    }
+}