Cryptic error message when the Findbugs jar is missing in the classpath

[ipkiss42]

Lombok fails with a non-intuitive error message when findbugs is missing in the classpath.

Here is a script to reproduce the bug, explanations follow:

#!/bin/sh

# Where to reproduce the bug. Do not choose an existing directory!
WORK_DIR=/tmp/lombok-bug
# Configure the paths here
JAVA_HOME=/path/to/jdk1.8
LOMBOK_JAR=/path/to/lombok.jar
FINDBUGS_JAR=/path/to/findbugs.jar

# Secondary variables
OUTPUT_DIR=$WORK_DIR/output
IMPORTED_FILE=$WORK_DIR/tmp/Foo.java
MAIN_FILE=$WORK_DIR/Bar.java

rm -rf $WORK_DIR

echo "Creating files"

# Create imported file
mkdir -p $WORK_DIR/tmp
cat > $IMPORTED_FILE << EOF
package tmp;

import lombok.Value;

@Value
public class Foo {}
EOF

# Create main file
cat > $MAIN_FILE << EOF
import tmp.Foo;
import lombok.Value;

@Value
public class Bar {}
EOF

# Create Lombok config file
echo "lombok.extern.findbugs.addSuppressFBWarnings = true" > $WORK_DIR/lombok.config

# Compile
echo "Compiling $IMPORTED_FILE"
mkdir -p "$OUTPUT_DIR"
$JAVA_HOME/bin/javac -d "$OUTPUT_DIR" -classpath "$FINDBUGS_JAR:$LOMBOK_JAR" "$IMPORTED_FILE"
echo "Compiling $MAIN_FILE"
$JAVA_HOME/bin/javac -d "$OUTPUT_DIR" -classpath "$OUTPUT_DIR:$LOMBOK_JAR" "$MAIN_FILE"

Note: to run the script, do not forget to update the 4 first variables appropriately.

The script creates 2 almost empty Java files (tmp.Foo and Bar). The first one is compiled with Findbugs in its classpath, but the second one is compiled without.
In addition, the script creates a lombok config file with lombok.extern.findbugs.addSuppressFBWarnings set to true.

The second file (Bar.java) imports the tmp.Foo class. When compiling it, javac is completely confused and thinks it has a bug. Here is the output of the script:

Creating files
Compiling /tmp/lombok-bug/tmp/Foo.java
Compiling /tmp/lombok-bug/Bar.java
warning: Error during the transformation of 'Bar'; post-compiler 'lombok.bytecode.PreventNullAnalysisRemover' caused an exception: java.lang.ArrayIndexOutOfBoundsException: 8
warning: Error during the transformation of 'Bar'; post-compiler 'lombok.bytecode.SneakyThrowsRemover' caused an exception: java.lang.ArrayIndexOutOfBoundsException: 8
An exception has occurred in the compiler (1.8.0_77). Please file a bug against the Java compiler via the Java bug reporting page (http://bugreport.java.com) after checking the Bug Database (http://bugs.java.com) for duplicates. Include your program and the following diagnostic in your report. Thank you.
java.lang.AssertionError: typeSig ERROR
        at com.sun.tools.javac.code.Types$SignatureGenerator.assembleSig(Types.java:4796)
        at com.sun.tools.javac.jvm.ClassWriter$CWSignatureGenerator.assembleSig(ClassWriter.java:299)
        at com.sun.tools.javac.jvm.ClassWriter.typeSig(ClassWriter.java:342)
        at com.sun.tools.javac.jvm.ClassWriter.writeCompoundAttribute(ClassWriter.java:891)
        at com.sun.tools.javac.jvm.ClassWriter.writeJavaAnnotations(ClassWriter.java:759)
        at com.sun.tools.javac.jvm.ClassWriter.writeMemberAttrs(ClassWriter.java:628)
        at com.sun.tools.javac.jvm.ClassWriter.writeMethod(ClassWriter.java:1133)
        at com.sun.tools.javac.jvm.ClassWriter.writeMethods(ClassWriter.java:1603)
        at com.sun.tools.javac.jvm.ClassWriter.writeClassFile(ClassWriter.java:1693)
        at com.sun.tools.javac.jvm.ClassWriter.writeClass(ClassWriter.java:1621)
        at com.sun.tools.javac.main.JavaCompiler.genCode(JavaCompiler.java:746)
        at com.sun.tools.javac.main.JavaCompiler.generate(JavaCompiler.java:1572)
        at com.sun.tools.javac.main.JavaCompiler.generate(JavaCompiler.java:1536)
        at com.sun.tools.javac.main.JavaCompiler.compile2(JavaCompiler.java:901)
        at com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:860)
        at com.sun.tools.javac.main.Main.compile(Main.java:523)
        at com.sun.tools.javac.main.Main.compile(Main.java:381)
        at com.sun.tools.javac.main.Main.compile(Main.java:370)
        at com.sun.tools.javac.main.Main.compile(Main.java:361)
        at com.sun.tools.javac.Main.compile(Main.java:56)
        at com.sun.tools.javac.Main.main(Main.java:42)

Instead of this cryptic message, the expected behavior is simple: Lombok should tell me that the Findbugs jar is missing in the classpath, ideally by outputting the FQCN of the Findbugs class that it expects to find in the classpath.

[eatdrinksleepcode]

Just hit this with lombok 1.16.8 while making some changes to my Gradle configuration. This was the only search result; if it hadn't been here, there's no telling how long it would have taken me to find, if I found it at all.