Write raw javac output to a log file

Author: mensinda

plexus-compilers/plexus-compiler-javac/src/main/java/org/codehaus/plexus/compiler/javac/JavacCompiler.java

@@ -56,8 +56,13 @@
 import java.net.MalformedURLException;
 import java.net.URL;
 import java.net.URLClassLoader;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.text.SimpleDateFormat;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Date;
 import java.util.Deque;
 import java.util.HashSet;
 import java.util.List;
@@ -643,6 +648,14 @@ protected CompilerResult compileOutOfProcess(CompilerConfiguration config, Strin
                 getLog().debug("Compiler output:{}{}", EOL, out.getOutput());
             }
 
+            Path logsDir = config.getBuildDirectory().toPath().resolve("compiler-logs");
+            if (!Files.exists(logsDir)) {
+                Files.createDirectories(logsDir);
+            }
+            SimpleDateFormat dateFormat = new SimpleDateFormat("'javac'_yyyy-MM-dd'T'HH_mm_ss.'log'");
+            String logFileName = dateFormat.format(new Date());
+            Files.write(logsDir.resolve(logFileName), out.getOutput().getBytes(StandardCharsets.UTF_8));
+
             messages = parseModernStream(returnCode, new BufferedReader(new StringReader(out.getOutput())));
         } catch (CommandLineException | IOException e) {
             throw new CompilerException("Error while executing the external compiler.", e);