Improve javac error output parsing - Fix #336 (#337)

Instead of two separate 'while' loops, one inline and one in an extra
method, parsing stack traces after finding error messages specific to
the English locale of the JDK, now there is generic stack trace parsing,
which works in these two cases independent of locale and also in others
previously not covered.

For backward compatibility, the Javac localized message 'javac.msg.bug'
("An exception has occurred in the compiler ... Please file a bug") is
salvaged in a locale-independent way, matching on error reporting URLs
always occurring in all JDK locales (English, Japanese, Chinese, German
as of JDK 21).

Fixes #336

Author: kriegaex

plexus-compilers/plexus-compiler-javac/pom.xml

@@ -27,6 +27,11 @@
       <artifactId>junit-jupiter-api</artifactId>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter-params</artifactId>
+      <scope>test</scope>
+    </dependency>
     <dependency>
       <groupId>org.hamcrest</groupId>
       <artifactId>hamcrest</artifactId>

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

@@ -65,6 +65,7 @@
 import java.util.Properties;
 import java.util.StringTokenizer;
 import java.util.concurrent.ConcurrentLinkedDeque;
+import java.util.regex.Pattern;
 
 import org.codehaus.plexus.compiler.AbstractCompiler;
 import org.codehaus.plexus.compiler.CompilerConfiguration;
@@ -627,6 +628,16 @@ private static CompilerResult compileInProcess0(Class<?> javacClass, String[] ar
         return new CompilerResult(success, messages);
     }
 
+    // Match ~95% of existing JDK exception name patterns (last checked for JDK 21)
+    private static final Pattern STACK_TRACE_FIRST_LINE = Pattern.compile("^(?:[\\w+.-]+\\.)[\\w$]*?(?:"
+            + "Exception|Error|Throwable|Failure|Result|Abort|Fault|ThreadDeath|Overflow|Warning|"
+            + "NotSupported|NotFound|BadArgs|BadClassFile|Illegal|Invalid|Unexpected|Unchecked|Unmatched\\w+"
+            + ").*$");
+
+    // Match exception causes, existing and omitted stack trace elements
+    private static final Pattern STACK_TRACE_OTHER_LINE =
+            Pattern.compile("^(?:Caused by:\\s.*|\\s*at .*|\\s*\\.\\.\\.\\s\\d+\\smore)$");
+
     /**
      * Parse the output from the compiler into a list of CompilerMessage objects
      *
@@ -643,13 +654,14 @@ static List<CompilerMessage> parseModernStream(int exitCode, BufferedReader inpu
         StringBuilder buffer = new StringBuilder();
 
         boolean hasPointer = false;
+        int stackTraceLineCount = 0;
 
         while (true) {
             line = input.readLine();
 
             if (line == null) {
                 // javac output not detected by other parsing
-                // maybe better to ignore only the summary an mark the rest as error
+                // maybe better to ignore only the summary and mark the rest as error
                 String bufferAsString = buffer.toString();
                 if (buffer.length() > 0) {
                     if (bufferAsString.startsWith("javac:")) {
@@ -659,26 +671,44 @@ static List<CompilerMessage> parseModernStream(int exitCode, BufferedReader inpu
                     } else if (hasPointer) {
                         // A compiler message remains in buffer at end of parse stream
                         errors.add(parseModernError(exitCode, bufferAsString));
+                    } else if (stackTraceLineCount > 0) {
+                        // Extract stack trace from end of buffer
+                        String[] lines = bufferAsString.split("\\R");
+                        int linesTotal = lines.length;
+                        buffer = new StringBuilder();
+                        int firstLine = linesTotal - stackTraceLineCount;
+
+                        // Salvage Javac localized message 'javac.msg.bug' ("An exception has occurred in the
+                        // compiler ... Please file a bug")
+                        if (firstLine > 0) {
+                            final String lineBeforeStackTrace = lines[firstLine - 1];
+                            // One of those two URL substrings should always appear, without regard to JVM locale.
+                            // TODO: Update, if the URL changes, last checked for JDK 21.
+                            if (lineBeforeStackTrace.contains("java.sun.com/webapps/bugreport")
+                                    || lineBeforeStackTrace.contains("bugreport.java.com")) {
+                                firstLine--;
+                            }
+                        }
+
+                        // Note: For message 'javac.msg.proc.annotation.uncaught.exception' ("An annotation processor
+                        // threw an uncaught exception"), there is no locale-independent substring, and the header is
+                        // also multi-line. It was discarded in the removed method 'parseAnnotationProcessorStream',
+                        // and we continue to do so.
+
+                        for (int i = firstLine; i < linesTotal; i++) {
+                            buffer.append(lines[i]).append(EOL);
+                        }
+                        errors.add(new CompilerMessage(buffer.toString(), CompilerMessage.Kind.ERROR));
                     }
                 }
                 return errors;
             }
 
-            // A compiler error occurred, treat everything that follows as part of the error.
-            if (line.startsWith("An exception has occurred in the compiler")) {
-                buffer = new StringBuilder();
-
-                while (line != null) {
-                    buffer.append(line);
-                    buffer.append(EOL);
-                    line = input.readLine();
-                }
-
-                errors.add(new CompilerMessage(buffer.toString(), CompilerMessage.Kind.ERROR));
-                return errors;
-            } else if (line.startsWith("An annotation processor threw an uncaught exception.")) {
-                CompilerMessage annotationProcessingError = parseAnnotationProcessorStream(input);
-                errors.add(annotationProcessingError);
+            if (stackTraceLineCount == 0 && STACK_TRACE_FIRST_LINE.matcher(line).matches()
+                    || STACK_TRACE_OTHER_LINE.matcher(line).matches()) {
+                stackTraceLineCount++;
+            } else {
+                stackTraceLineCount = 0;
             }
 
             // new error block?
@@ -714,21 +744,6 @@ static List<CompilerMessage> parseModernStream(int exitCode, BufferedReader inpu
         }
     }
 
-    private static CompilerMessage parseAnnotationProcessorStream(final BufferedReader input) throws IOException {
-        String line = input.readLine();
-        final StringBuilder buffer = new StringBuilder();
-
-        while (line != null) {
-            if (!line.startsWith("Consult the following stack trace for details.")) {
-                buffer.append(line);
-                buffer.append(EOL);
-            }
-            line = input.readLine();
-        }
-
-        return new CompilerMessage(buffer.toString(), CompilerMessage.Kind.ERROR);
-    }
-
     private static boolean isMisc(String line) {
         return startsWithPrefix(line, MISC_PREFIXES);
     }

plexus-compilers/plexus-compiler-javac/src/test/java/org/codehaus/plexus/compiler/javac/ErrorMessageParserTest.java

@@ -28,20 +28,25 @@
 import java.io.StringReader;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.stream.Stream;
 
 import org.codehaus.plexus.compiler.CompilerMessage;
 import org.codehaus.plexus.util.Os;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
+import static org.hamcrest.CoreMatchers.endsWith;
+import static org.hamcrest.CoreMatchers.startsWith;
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.hasSize;
 import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.notNullValue;
-import static org.hamcrest.core.StringEndsWith.endsWith;
-import static org.hamcrest.core.StringStartsWith.startsWith;
 
 /**
  * @author <a href="mailto:trygvis@inamo.no">Trygve Laugst&oslash;l</a>
+ * @author Alexander Kriegisch
  */
 public class ErrorMessageParserTest {
     private static final String EOL = System.getProperty("line.separator");
@@ -775,19 +780,79 @@ public void testJava7Error() throws Exception {
         assertThat(message2.getEndLine(), is(3));
     }
 
-    @Test
-    public void testBugParade() throws Exception {
-        String out = "An exception has occurred in the compiler (1.7.0_80). "
-                + "Please file a bug at the Java Developer Connection (http://java.sun.com/webapps/bugreport)  after checking the Bug Parade for duplicates. "
-                + "Include your program and the following diagnostic in your report.  Thank you." + EOL
-                + "com.sun.tools.javac.code.Symbol$CompletionFailure: class file for java.util.Optional not found";
+    @ParameterizedTest(name = "{0}")
+    @MethodSource("testBugParade_args")
+    public void testBugParade(String jdkAndLocale, String stackTraceHeader) throws Exception {
+        String stackTraceWithHeader = stackTraceHeader + stackTraceInternalCompilerError;
 
-        List<CompilerMessage> compilerErrors =
-                JavacCompiler.parseModernStream(4, new BufferedReader(new StringReader(out)));
+        List<CompilerMessage> compilerMessages =
+                JavacCompiler.parseModernStream(4, new BufferedReader(new StringReader(stackTraceWithHeader)));
 
-        assertThat(compilerErrors, notNullValue());
+        assertThat(compilerMessages, notNullValue());
+        assertThat(compilerMessages, hasSize(1));
 
-        assertThat(compilerErrors.size(), is(1));
+        String message = compilerMessages.get(0).getMessage().replaceAll(EOL, "\n");
+        // Parser retains stack trace header
+        assertThat(message, startsWith(stackTraceHeader));
+        assertThat(message, endsWith(stackTraceInternalCompilerError));
+    }
+
+    private static final String stackTraceInternalCompilerError =
+            "\tat com.sun.tools.javac.comp.MemberEnter.baseEnv(MemberEnter.java:1388)\n"
+                    + "\tat com.sun.tools.javac.comp.MemberEnter.complete(MemberEnter.java:1046)\n"
+                    + "\tat com.sun.tools.javac.code.Symbol.complete(Symbol.java:574)\n"
+                    + "\tat com.sun.tools.javac.code.Symbol$ClassSymbol.complete(Symbol.java:1037)\n"
+                    + "\tat com.sun.tools.javac.code.Symbol$ClassSymbol.flags(Symbol.java:973)\n"
+                    + "\tat com.sun.tools.javac.code.Symbol$ClassSymbol.getKind(Symbol.java:1101)\n"
+                    + "\tat com.sun.tools.javac.code.Kinds.kindName(Kinds.java:162)\n"
+                    + "\tat com.sun.tools.javac.comp.Check.duplicateError(Check.java:329)\n"
+                    + "\tat com.sun.tools.javac.comp.Check.checkUnique(Check.java:3435)\n"
+                    + "\tat com.sun.tools.javac.comp.Enter.visitTypeParameter(Enter.java:454)\n"
+                    + "\tat com.sun.tools.javac.tree.JCTree$JCTypeParameter.accept(JCTree.java:2224)\n"
+                    + "\tat com.sun.tools.javac.comp.Enter.classEnter(Enter.java:258)\n"
+                    + "\tat com.sun.tools.javac.comp.Enter.classEnter(Enter.java:272)\n"
+                    + "\tat com.sun.tools.javac.comp.Enter.visitClassDef(Enter.java:418)\n"
+                    + "\tat com.sun.tools.javac.tree.JCTree$JCClassDecl.accept(JCTree.java:693)\n"
+                    + "\tat com.sun.tools.javac.comp.Enter.classEnter(Enter.java:258)\n"
+                    + "\tat com.sun.tools.javac.comp.Enter.classEnter(Enter.java:272)\n"
+                    + "\tat com.sun.tools.javac.comp.Enter.visitTopLevel(Enter.java:334)\n"
+                    + "\tat com.sun.tools.javac.tree.JCTree$JCCompilationUnit.accept(JCTree.java:518)\n"
+                    + "\tat com.sun.tools.javac.comp.Enter.classEnter(Enter.java:258)\n"
+                    + "\tat com.sun.tools.javac.comp.Enter.classEnter(Enter.java:272)\n"
+                    + "\tat com.sun.tools.javac.comp.Enter.complete(Enter.java:486)\n"
+                    + "\tat com.sun.tools.javac.comp.Enter.main(Enter.java:471)\n"
+                    + "\tat com.sun.tools.javac.main.JavaCompiler.enterTrees(JavaCompiler.java:982)\n"
+                    + "\tat com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:857)\n"
+                    + "\tat com.sun.tools.javac.main.Main.compile(Main.java:523)\n"
+                    + "\tat com.sun.tools.javac.main.Main.compile(Main.java:381)\n"
+                    + "\tat com.sun.tools.javac.main.Main.compile(Main.java:370)\n"
+                    + "\tat com.sun.tools.javac.main.Main.compile(Main.java:361)\n"
+                    + "\tat com.sun.tools.javac.Main.compile(Main.java:56)\n"
+                    + "\tat com.sun.tools.javac.Main.main(Main.java:42)\n";
+
+    private static Stream<Arguments> testBugParade_args() {
+        return Stream.of(
+                Arguments.of(
+                        "JDK 8 English",
+                        "An exception has occurred in the compiler ({0}). Please file a bug at the Java Developer Connection (http://java.sun.com/webapps/bugreport)  after checking the Bug Parade for duplicates. Include your program and the following diagnostic in your report.  Thank you.\n"),
+                Arguments.of(
+                        "JDK 8 Japanese",
+                        "コンパイラで例外が発生しました({0})。Bug Paradeで重複がないかをご確認のうえ、Java Developer Connection (http://java.sun.com/webapps/bugreport)でbugの登録をお願いいたします。レポートには、そのプログラムと下記の診断内容を含めてください。ご協力ありがとうございます。\n"),
+                Arguments.of(
+                        "JDK 8 Chinese",
+                        "编译器 ({0}) 中出现异常错误。 如果在 Bug Parade 中没有找到该错误, 请在 Java Developer Connection (http://java.sun.com/webapps/bugreport) 中建立 Bug。请在报告中附上您的程序和以下诊断信息。谢谢。\n"),
+                Arguments.of(
+                        "JDK 21 English",
+                        "An exception has occurred in the compiler ({0}). Please file a bug against the Java compiler via the Java bug reporting page (https://bugreport.java.com) after checking the Bug Database (https://bugs.java.com) for duplicates. Include your program, the following diagnostic, and the parameters passed to the Java compiler in your report. Thank you.\n"),
+                Arguments.of(
+                        "JDK 21 Japanese",
+                        "コンパイラで例外が発生しました({0})。バグ・データベース(https://bugs.java.com)で重複がないかをご確認のうえ、Javaのバグ・レポート・ページ(https://bugreport.java.com)から、Javaコンパイラに対するバグの登録をお願いいたします。レポートには、該当のプログラム、次の診断内容、およびJavaコンパイラに渡されたパラメータをご入力ください。ご協力ありがとうございます。\n"),
+                Arguments.of(
+                        "JDK 21 Chinese",
+                        "编译器 ({0}) 中出现异常错误。如果在 Bug Database (https://bugs.java.com) 中没有找到有关该错误的 Java 编译器 Bug，请通过 Java Bug 报告页 (https://bugreport.java.com) 提交 Java 编译器 Bug。请在报告中附上您的程序、以下诊断信息以及传递到 Java 编译器的参数。谢谢。\n"),
+                Arguments.of(
+                        "JDK 21 German",
+                        "Im Compiler ({0}) ist eine Ausnahme aufgetreten. Erstellen Sie auf der Java-Seite zum Melden von Bugs (https://bugreport.java.com) einen Bugbericht, nachdem Sie die Bugdatenbank (https://bugs.java.com) auf Duplikate geprüft haben. Geben Sie in Ihrem Bericht Ihr Programm, die folgende Diagnose und die Parameter an, die Sie dem Java-Compiler übergeben haben. Vielen Dank.\n"));
     }
 
     @Test