ERROR with antlr4-maven-plugin

[Hans Uhlig]

While attempting to build a test project from here https://github.com/huhlig/essex
<plugin>
  <groupId>org.antlr</groupId>
  <artifactId>antlr4-maven-plugin</artifactId>
  <version>4.0-SNAPSHOT</version>
  <executions>
    <execution>
      <goals>
        <goal>antlr</goal>
      </goals>
    </execution>
  </executions>
  <configuration>
    <sourceDirectory>${project.basedir}/src/main/antlr4</sourceDirectory>
    <outputDirectory>${project.basedir}/target/generated-sources/antlr4</outputDirectory>
  </configuration>
</plugin>

I am getting the following output:

ANTLR: Output: C:\Users\huhlig\Dropbox\Projects\Essex\target\generated-sources\antlr4
ANTLR: Library: C:\Users\huhlig\Dropbox\Projects\Essex\src\main\antlr4\imports
ANTLR: report              : false
ANTLR: printGrammar        : false
ANTLR: debug               : false
ANTLR: profile             : false
ANTLR: atn                 : false
ANTLR: trace               : false
ANTLR: messageFormat       : antlr
ANTLR: maxSwitchCaseLabels : 300
ANTLR: minSwitchAlts       : 0
ANTLR: verbose             : true
Grammar file 'C:\Users\huhlig\Dropbox\Projects\Essex\src\main\antlr4\Essex.g4' detected.
  ... relative path is: null\Essex.g4
Output directory base will be C:\Users\huhlig\Dropbox\Projects\Essex\target\generated-sources\antlr4
ANTLR 4: Processing source directory C:\Users\huhlig\Dropbox\Projects\Essex\src\main\antlr4
Message{errorType=CANNOT_OPEN_FILE, args=[null\Essex.g4], e=java.io.FileNotFoundException: C:\Users\huhlig\Dropbox\Projects\Essex\src\main\antlr4\null\Essex.g4 (The system cannot find the path specified), fileName='null', line=-1, charPosition=-1}

The the listed directories I think should be the defaults but it seems to act the same way with or without explicitly specifying them.

[Hans Uhlig]

Adding the debug property to the configuration for antlr4-maven-plugin appears to add another error as well..

ANTLR: Output: C:\Users\huhlig\Dropbox\Projects\Essex\target\generated-sources\antlr4

ANTLR: Library: C:\Users\huhlig\Dropbox\Projects\Essex\src\main\antlr4\imports

ANTLR: report              : false

ANTLR: printGrammar        : false

ANTLR: debug               : true

ANTLR: profile             : false

ANTLR: atn                 : false

ANTLR: trace               : false

ANTLR: messageFormat       : antlr

ANTLR: maxSwitchCaseLabels : 300

ANTLR: minSwitchAlts       : 0

ANTLR: verbose             : true

Grammar file 'C:\Users\huhlig\Dropbox\Projects\Essex\src\main\antlr4\Essex.g4' detected.

  ... relative path is: null\Essex.g4

error(2):  unknown command-line option -debug

Output directory base will be C:\Users\huhlig\Dropbox\Projects\Essex\target\generated-sources\antlr4

ANTLR 4: Processing source directory C:\Users\huhlig\Dropbox\Projects\Essex\src\main\antlr4

Message{errorType=CANNOT_OPEN_FILE, args=[null\Essex.g4], e=java.io.FileNotFoundException: C:\Users\huhlig\Dropbox\Projects\Essex\src\main\antlr4\null\Essex.g4 (The system cannot find the path specified), fileName='null', line=-1, charPosition=-1}