SCANJLIB-250 Preserve stderr/stdout when the command fails early

Author: henryju

lib/src/main/java/org/sonarsource/scanner/lib/internal/facade/forked/JavaRunner.java

@@ -56,15 +56,15 @@ public boolean execute(List<String> args, @Nullable String input, Consumer<Strin
         LOG.debug("Executing: {}", String.join(" ", command));
       }
       Process process = new ProcessBuilder(command).start();
-      if (input != null) {
-        try (var stdin = process.getOutputStream(); var osw = new OutputStreamWriter(stdin, StandardCharsets.UTF_8)) {
-          osw.write(input);
-        }
-      }
       var stdoutConsummer = new StreamGobbler(process.getInputStream(), stdOutConsummer);
       var stdErrConsummer = new StreamGobbler(process.getErrorStream(), stderr -> LOG.error("[stderr] {}", stderr));
       stdErrConsummer.start();
       stdoutConsummer.start();
+      if (input != null && process.isAlive()) {
+        try (var stdin = process.getOutputStream(); var osw = new OutputStreamWriter(stdin, StandardCharsets.UTF_8)) {
+          osw.write(input);
+        }
+      }
       var exitCode = process.waitFor();
       stdoutConsummer.join();
       stdErrConsummer.join();

lib/src/test/java/org/sonarsource/scanner/lib/internal/facade/forked/JavaRunnerTest.java

@@ -59,6 +59,15 @@ void execute_shouldLogProcessStdError() {
     assertThat(logTester.logs(Level.ERROR)).isNotEmpty().allMatch(s -> s.startsWith("[stderr] "));
   }
 
+  @Test
+  void execute_shouldLogProcessStdError_and_skip_writing_to_stdin_when_process_fails_early() {
+    JavaRunner runner = new JavaRunner(Paths.get("java"), JreCacheHit.DISABLED);
+    List<String> command = List.of("-xyz");
+    assertThat(runner.execute(command, "test", stdOut::add)).isFalse();
+
+    assertThat(logTester.logs(Level.ERROR)).anyMatch(s -> s.startsWith("[stderr] Unrecognized option: -xyz"));
+  }
+
   @Test
   void execute_whenInvalidRunner_shouldFail() {
     JavaRunner runner = new JavaRunner(Paths.get("invalid-runner"), JreCacheHit.DISABLED);