gradle generated files fail to compile

Question

I am trying to get a JavaCC plugin working properly with Gradle. The plugin generates .java files correctly, but then during the compileJavaC task it crashes and burns with cannot find symbol errors. My JavaCC .jj file contains code that references other java files that are not generated, and I am guessing that the compileJava task tries to compile the generated code without providing a reference to the non-generated code.

Here is a minimum breaking example. build.gradle:

apply plugin: 'java'

//compile .jj file in src/main/javacc
buildscript {
    repositories {
        mavenCentral()
    }
    dependencies {
        classpath group: 'ca.coglinc', name: 'javacc-gradle-plugin', version: '1.0.0'
    }
}
apply plugin: 'javacc'

src/main/MyClass.java:

public class MyClass {
    public MyClass(){

    }
}

and src/main/javacc/MyParser.jj:

options
{}
PARSER_BEGIN(MyParser)
import java.util.*;
public class MyParser {
    public static void main(String[] args) throws ParseException {
        MyClass mc = new MyClass();
    }
}
PARSER_END(MyParser)

SKIP:
{
    " "
}

TOKEN:
{
     <ANYTHING:  ~[]>
}


void production():
{}
{
    (<ANYTHING>)+
}

Running gradle build gives the following:

gradle build
:compileJavacc
Java Compiler Compiler Version 5.0 (Parser Generator)
(type "javacc" with no arguments for help)
Reading from file C:\Users\Nate Glenn\Desktop\java_workspace\test-gradle-javacc\
src\main\javacc\MyParser.jj . . .
File "TokenMgrError.java" does not exist.  Will create one.
File "ParseException.java" does not exist.  Will create one.
File "Token.java" does not exist.  Will create one.
File "SimpleCharStream.java" does not exist.  Will create one.
Parser generated successfully.
:compileJavaC:\Users\Nate Glenn\Desktop\java_workspace\test-gradle-javacc\build\
generated\javacc\MyParser.java:5: error: cannot find symbol
        MyClass mc = new MyClass();
        ^
  symbol:   class MyClass
  location: class MyParser
C:\Users\Nate Glenn\Desktop\java_workspace\test-gradle-javacc\build\generated\ja
vacc\MyParser.java:5: error: cannot find symbol
        MyClass mc = new MyClass();
                         ^
  symbol:   class MyClass
  location: class MyParser
2 errors
 FAILED

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':compileJava'.
> Compilation failed; see the compiler error output for details.

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug
option to get more log output.

BUILD FAILED

Total time: 9.002 secs

How can I fix my Gradle build file so that javaCompileC correctly includes non-generated files when compiling the generated files?

Answer 1

Your source tree for MyClass is incorrect. It should be src/main/java/MyClass.java. In gradle, just like maven, convention is that java files by default are in src/main/java, and since you're not overriding this in your build.gradle file, I assume this is just an error on your part. The plugin correctly adds the JavaCC output path to the compileJava task's classpath, so if you create your java classes in the correct path for the compileJava task, everything should be fine :)

Just tried your example this way and it works.

By the way, thanks for your contribution to the plugin.