From f9ba471da18307ca98c3b8d617275b089961b7b8 Mon Sep 17 00:00:00 2001
From: Andrew Fiddian-Green <software@whitebear.ch>
Date: Sat, 16 Jan 2021 21:20:09 +0000
Subject: [PATCH] [executeCommandLine] should return STDERR if STDOUT is empty
 (#2114)

Signed-off-by: Andrew Fiddian-Green <software@whitebear.ch>
---
 .../openhab/core/io/net/exec/ExecUtil.java    | 31 +++----------------
 .../core/io/net/exec/ExecUtilTest.java        | 13 ++++++++
 2 files changed, 17 insertions(+), 27 deletions(-)

diff --git a/bundles/org.openhab.core.io.net/src/main/java/org/openhab/core/io/net/exec/ExecUtil.java b/bundles/org.openhab.core.io.net/src/main/java/org/openhab/core/io/net/exec/ExecUtil.java
index afc0b51b62f..0b568e0e094 100644
--- a/bundles/org.openhab.core.io.net/src/main/java/org/openhab/core/io/net/exec/ExecUtil.java
+++ b/bundles/org.openhab.core.io.net/src/main/java/org/openhab/core/io/net/exec/ExecUtil.java
@@ -78,9 +78,8 @@ public static void executeCommandLine(String... commandLine) {
 
         Process processTemp = null;
         Future<String> outputFuture = null;
-        Future<String> errorFuture = null;
         cleanup: try {
-            Process process = processTemp = new ProcessBuilder(commandLine).start();
+            Process process = processTemp = new ProcessBuilder(commandLine).redirectErrorStream(true).start();
 
             outputFuture = executor.submit(() -> {
                 try (InputStream inputStream = process.getInputStream();
@@ -91,32 +90,13 @@ public static void executeCommandLine(String... commandLine) {
                 }
             });
 
-            errorFuture = executor.submit(() -> {
-                try (InputStream inputStream = process.getErrorStream();
-                        BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream))) {
-                    StringWriter output = new StringWriter();
-                    reader.transferTo(output);
-                    return output.toString();
-                }
-            });
-            int exitCode;
             if (timeout == null) {
-                exitCode = process.waitFor();
-            } else if (process.waitFor(timeout.toMillis(), TimeUnit.MILLISECONDS)) {
-                exitCode = process.exitValue();
-            } else {
+                process.waitFor();
+            } else if (!process.waitFor(timeout.toMillis(), TimeUnit.MILLISECONDS)) {
                 logger.warn("Timeout occurred when executing commandLine '{}'", Arrays.toString(commandLine));
                 break cleanup;
             }
-            if (exitCode == 0) {
-                return outputFuture.get();
-            } else {
-                if (logger.isDebugEnabled()) {
-                    logger.debug("exit code '{}', result '{}', errors '{}'", exitCode, outputFuture.get(),
-                            errorFuture.get());
-                }
-                return errorFuture.get();
-            }
+            return outputFuture.get();
         } catch (ExecutionException e) {
             if (logger.isDebugEnabled()) {
                 logger.warn("Error occurred when executing commandLine '{}'", Arrays.toString(commandLine),
@@ -139,9 +119,6 @@ public static void executeCommandLine(String... commandLine) {
         if (outputFuture != null) {
             outputFuture.cancel(true);
         }
-        if (errorFuture != null) {
-            errorFuture.cancel(true);
-        }
         return null;
     }
 }
diff --git a/bundles/org.openhab.core.io.net/src/test/java/org/openhab/core/io/net/exec/ExecUtilTest.java b/bundles/org.openhab.core.io.net/src/test/java/org/openhab/core/io/net/exec/ExecUtilTest.java
index 8c5373c035f..93fe5e474d7 100644
--- a/bundles/org.openhab.core.io.net/src/test/java/org/openhab/core/io/net/exec/ExecUtilTest.java
+++ b/bundles/org.openhab.core.io.net/src/test/java/org/openhab/core/io/net/exec/ExecUtilTest.java
@@ -62,4 +62,17 @@ private boolean isWindowsSystem() {
         String osName = System.getProperty("os.name").toLowerCase();
         return osName.indexOf("windows") >= 0;
     }
+
+    @Test
+    public void testExecuteCommandLineAndWaitStdErrRedirection() {
+        final String result;
+        if (isWindowsSystem()) {
+            result = ExecUtil.executeCommandLineAndWaitResponse(Duration.ofSeconds(1), "cmd", "/c", "dir", "xxx.xxx",
+                    "1>", "nul");
+        } else {
+            result = ExecUtil.executeCommandLineAndWaitResponse(Duration.ofSeconds(1), "ls", "xxx.xxx");
+        }
+        assertNotNull(result);
+        assertNotEquals("", result);
+    }
 }