feat: simplifies the replFrege task

The replFregeTask has the following new logic:
1. Compiles the specified fregeRepl module (either in the
   `build.gradle` via command line option `--replModule=...`) and all
   its dependencies.
2. Sets up the correct classpath so that dependent modules don't have
to be imported manually. In addition, it solves the shadowing problem by
removing the replModule java and class file from the classpath.
3. It prints one single command to directly start the repl and load the
   specified module.

Bonus: I designed the task so that you can even automate step 3 with
the following bash command: `eval $(./gradlew -q replFrege)`.

6 files changed, 179 insertions, 34 deletions

diff --git a/src/functionalTest/java/ch/fhnw/thga/gradleplugins/CompileFregeTaskFunctionalTest.java b/src/functionalTest/java/ch/fhnw/thga/gradleplugins/CompileFregeTaskFunctionalTest.java
index 31e6d05..90a459c 100644
--- a/src/functionalTest/java/ch/fhnw/thga/gradleplugins/CompileFregeTaskFunctionalTest.java
+++ b/src/functionalTest/java/ch/fhnw/thga/gradleplugins/CompileFregeTaskFunctionalTest.java
@@ -8,6 +8,7 @@ import static ch.fhnw.thga.gradleplugins.SharedFunctionalTestLogic.runGradleTask
 import static ch.fhnw.thga.gradleplugins.SharedFunctionalTestLogic.NEW_LINE;
 import static ch.fhnw.thga.gradleplugins.SharedFunctionalTestLogic.MINIMAL_BUILD_FILE_CONFIG;
 import static ch.fhnw.thga.gradleplugins.SharedFunctionalTestLogic.COMPLETION_FR;
+import static ch.fhnw.thga.gradleplugins.SharedFunctionalTestLogic.assertFileExists;
 import static org.gradle.testkit.runner.TaskOutcome.FAILED;
 import static org.gradle.testkit.runner.TaskOutcome.FROM_CACHE;
 import static org.gradle.testkit.runner.TaskOutcome.SUCCESS;
@@ -31,17 +32,6 @@ import ch.fhnw.thga.gradleplugins.fregeproject.FregeSourceFile;
 
 public class CompileFregeTaskFunctionalTest
 {
-    private static final boolean assertFileExists(
-        File testProjectDir,
-        String relativeFilePath)
-    {
-        return testProjectDir
-        .toPath()
-        .resolve(relativeFilePath)
-        .toFile()
-        .exists();
-    }
-
     @Nested
     @IndicativeSentencesGeneration(
         separator = " -> ",
@@ -159,11 +149,11 @@ public class CompileFregeTaskFunctionalTest
             );
             assertFileExists(
                 testProjectDir,
-                "build/classes/main/frege/ch/fhnw/thga/Completion.java"
+                "build/frege/ch/fhnw/thga/Completion.java"
             );
             assertFileExists(
                 testProjectDir,
-                "build/classes/main/frege/ch/fhnw/thga/Completion.class"
+                "build/frege/ch/fhnw/thga/Completion.class"
             );
         }
         @Test
diff --git a/src/functionalTest/java/ch/fhnw/thga/gradleplugins/ReplFregeTaskFunctionalTest.java b/src/functionalTest/java/ch/fhnw/thga/gradleplugins/ReplFregeTaskFunctionalTest.java
index 979d1d4..52bfbff 100644
--- a/src/functionalTest/java/ch/fhnw/thga/gradleplugins/ReplFregeTaskFunctionalTest.java
+++ b/src/functionalTest/java/ch/fhnw/thga/gradleplugins/ReplFregeTaskFunctionalTest.java
@@ -1,15 +1,18 @@
 package ch.fhnw.thga.gradleplugins;
 
+import static ch.fhnw.thga.gradleplugins.FregeExtension.DEFAULT_RELATIVE_SOURCE_DIR;
 import static ch.fhnw.thga.gradleplugins.FregePlugin.REPL_FREGE_TASK_NAME;
 import static ch.fhnw.thga.gradleplugins.SharedFunctionalTestLogic.COMPLETION_FR;
 import static ch.fhnw.thga.gradleplugins.SharedFunctionalTestLogic.MINIMAL_BUILD_FILE_CONFIG;
+import static ch.fhnw.thga.gradleplugins.SharedFunctionalTestLogic.NEW_LINE;
+import static ch.fhnw.thga.gradleplugins.SharedFunctionalTestLogic.assertFileDoesNotExist;
+import static ch.fhnw.thga.gradleplugins.SharedFunctionalTestLogic.assertFileExists;
 import static ch.fhnw.thga.gradleplugins.SharedFunctionalTestLogic.createFregeSection;
 import static ch.fhnw.thga.gradleplugins.SharedFunctionalTestLogic.runAndFailGradleTask;
 import static ch.fhnw.thga.gradleplugins.SharedFunctionalTestLogic.runGradleTask;
 import static org.gradle.testkit.runner.TaskOutcome.FAILED;
 import static org.gradle.testkit.runner.TaskOutcome.SUCCESS;
 import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.io.File;
@@ -24,6 +27,7 @@ import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;
 
 import ch.fhnw.thga.gradleplugins.fregeproject.FregeProjectBuilder;
+import ch.fhnw.thga.gradleplugins.fregeproject.FregeSourceFile;
 
 public class ReplFregeTaskFunctionalTest
 {
@@ -64,7 +68,79 @@ public class ReplFregeTaskFunctionalTest
                 result.task(":" + REPL_FREGE_TASK_NAME).getOutcome());
             assertTrue(result.getOutput().contains("java -cp"));
             assertTrue(result.getOutput().contains("frege3.25.84.jar"));
-            assertFalse(result.getOutput().contains("Completion.class"));
+            assertTrue(result.getOutput().contains(COMPLETION_FR.getFregeModulePath()));
+            assertFileDoesNotExist(
+                testProjectDir,
+                "build/classes/main/frege/ch/fhnw/thga/Completion.java"
+            );
+            assertFileDoesNotExist(
+                testProjectDir,
+                "build/classes/main/frege/ch/fhnw/thga/Completion.class"
+            );
+        }
+
+        @Test
+        void given_dependent_frege_files_with_command_line_repl_module_option(
+            @TempDir File testProjectDir)
+            throws Exception
+        {
+            String frobCode = String.join(
+                NEW_LINE,
+                "module ch.fhnw.thga.Frob where",
+                NEW_LINE,
+                NEW_LINE,
+                "import ch.fhnw.thga.Completion (complete)",
+                NEW_LINE,
+                "frob i = complete $ i + i",
+                NEW_LINE
+            );
+            FregeSourceFile frob_FR = new FregeSourceFile(
+                String.format(
+                    "%s/%s",
+                    DEFAULT_RELATIVE_SOURCE_DIR,
+                    "ch/fhnw/thga/Frob.fr"
+                ),
+                frobCode);
+            Project project = FregeProjectBuilder
+                .builder()
+                .projectRoot(testProjectDir)
+                .buildFile(MINIMAL_BUILD_FILE_CONFIG)
+                .fregeSourceFiles(() -> Stream.of(COMPLETION_FR, frob_FR))
+                .build();
+            
+            BuildResult result = runGradleTask(
+                testProjectDir,
+                REPL_FREGE_TASK_NAME,
+                "--replModule=ch.fhnw.thga.Frob"
+            );
+            
+            assertTrue(
+                project
+                .getTasks()
+                .getByName(REPL_FREGE_TASK_NAME)
+                instanceof ReplFregeTask);
+            assertEquals(
+                SUCCESS,
+                result.task(":" + REPL_FREGE_TASK_NAME).getOutcome());
+            assertTrue(result.getOutput().contains("java -cp"));
+            assertTrue(result.getOutput().contains("frege3.25.84.jar"));
+            assertTrue(result.getOutput().contains(frob_FR.getFregeModulePath()));
+            assertFileExists(
+                testProjectDir,
+                "build/classes/main/frege/ch/fhnw/thga/Completion.java"
+            );
+            assertFileExists(
+                testProjectDir,
+                "build/classes/main/frege/ch/fhnw/thga/Completion.class"
+            );
+            assertFileDoesNotExist(
+                testProjectDir,
+                "build/classes/main/frege/ch/fhnw/thga/Frob.java"
+            );
+            assertFileDoesNotExist(
+                testProjectDir,
+                "build/classes/main/frege/ch/fhnw/thga/Frob.class"
+            );
         }
     }
 
diff --git a/src/functionalTest/java/ch/fhnw/thga/gradleplugins/SharedFunctionalTestLogic.java b/src/functionalTest/java/ch/fhnw/thga/gradleplugins/SharedFunctionalTestLogic.java
index 51fa256..f935b28 100644
--- a/src/functionalTest/java/ch/fhnw/thga/gradleplugins/SharedFunctionalTestLogic.java
+++ b/src/functionalTest/java/ch/fhnw/thga/gradleplugins/SharedFunctionalTestLogic.java
@@ -3,6 +3,8 @@ package ch.fhnw.thga.gradleplugins;
 import static ch.fhnw.thga.gradleplugins.FregePlugin.FREGE_EXTENSION_NAME;
 import static ch.fhnw.thga.gradleplugins.FregePlugin.FREGE_PLUGIN_ID;
 import static ch.fhnw.thga.gradleplugins.GradleBuildFileConversionTest.createPluginsSection;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 import static ch.fhnw.thga.gradleplugins.FregeExtension.DEFAULT_RELATIVE_SOURCE_DIR;
 
 import java.io.BufferedWriter;
@@ -44,6 +46,32 @@ public class SharedFunctionalTestLogic
             NEW_LINE
         )
     );
+
+    public static final boolean fileExists(
+        File testProjectDir,
+        String relativeFilePath)
+    {
+        return testProjectDir
+        .toPath()
+        .resolve(relativeFilePath)
+        .toFile()
+        .exists();
+    }
+
+    public static final void assertFileExists(
+        File testProjectDir,
+        String relativeFilePath)
+    {
+        assertTrue(fileExists(testProjectDir, relativeFilePath));
+    }
+
+
+    public static final void assertFileDoesNotExist(
+        File testProjectDir,
+        String relativeFilePath)
+    {
+        assertFalse(fileExists(testProjectDir, relativeFilePath));
+    }
     
     static String createFregeSection(FregeDTO fregeDTO) 
    {
diff --git a/src/main/java/ch/fhnw/thga/gradleplugins/CompileFregeTask.java b/src/main/java/ch/fhnw/thga/gradleplugins/CompileFregeTask.java
index a3c42d2..a39a07b 100644
--- a/src/main/java/ch/fhnw/thga/gradleplugins/CompileFregeTask.java
+++ b/src/main/java/ch/fhnw/thga/gradleplugins/CompileFregeTask.java
@@ -11,6 +11,7 @@ import javax.inject.Inject;
 import org.gradle.api.DefaultTask;
 import org.gradle.api.file.DirectoryProperty;
 import org.gradle.api.file.RegularFileProperty;
+import org.gradle.api.logging.LogLevel;
 import org.gradle.api.model.ObjectFactory;
 import org.gradle.api.provider.ListProperty;
 import org.gradle.api.provider.Property;
@@ -30,7 +31,7 @@ import org.gradle.api.tasks.options.Option;
 @CacheableTask
 public abstract class CompileFregeTask extends DefaultTask {
     private static final String FREGE_FILES_GLOB_PATTERN = "**/*.fr";
-    private final JavaExec javaExec;
+    private JavaExec javaExec;
 
     @InputFile
     @PathSensitive(PathSensitivity.RELATIVE)
@@ -113,12 +114,18 @@ public abstract class CompileFregeTask extends DefaultTask {
     }
 
     @TaskAction
-    public void compileFrege() {
+    public void compileFrege()
+    {
+        this.getLogging().captureStandardOutput(LogLevel.LIFECYCLE);
         List<String> targetDirectoryArg = List.of(
             "-d",
-            getFregeOutputDir().getAsFile().get().getAbsolutePath());
-
-        javaExec.setClasspath(getProject().files(getFregeCompilerJar()))
-                .setArgs(buildCompilerArgsFromProperties(targetDirectoryArg)).exec();
+            getFregeOutputDir().getAsFile().get().getAbsolutePath()
+        );
+        javaExec.setClasspath(
+            getProject()
+            .files(getFregeCompilerJar()))
+            .setErrorOutput(System.out)
+            .setArgs(buildCompilerArgsFromProperties(targetDirectoryArg))
+            .exec();
     }
 }
\ No newline at end of file
diff --git a/src/main/java/ch/fhnw/thga/gradleplugins/FregePlugin.java b/src/main/java/ch/fhnw/thga/gradleplugins/FregePlugin.java
index 9b725ac..e1f410a 100644
--- a/src/main/java/ch/fhnw/thga/gradleplugins/FregePlugin.java
+++ b/src/main/java/ch/fhnw/thga/gradleplugins/FregePlugin.java
@@ -94,6 +94,7 @@ public class FregePlugin implements Plugin<Project>
                     setupFregeCompilerTask.get().getFregeCompilerOutputPath());
                 task.getFregeOutputDir().set(extension.getOutputDir());
                 task.getFregeDependencies().set(implementation.getAsPath());
+                task.getFregeMainSourceDir().set(extension.getMainSourceDir());
             }
         );
     }
diff --git a/src/main/java/ch/fhnw/thga/gradleplugins/ReplFregeTask.java b/src/main/java/ch/fhnw/thga/gradleplugins/ReplFregeTask.java
index 67af55e..1a47f8f 100644
--- a/src/main/java/ch/fhnw/thga/gradleplugins/ReplFregeTask.java
+++ b/src/main/java/ch/fhnw/thga/gradleplugins/ReplFregeTask.java
@@ -5,6 +5,8 @@ import org.gradle.api.DefaultTask;
 import org.gradle.api.file.DirectoryProperty;
 import org.gradle.api.file.FileTree;
 import org.gradle.api.file.RegularFileProperty;
+import org.gradle.api.logging.Logger;
+import org.gradle.api.logging.Logging;
 import org.gradle.api.provider.Property;
 import org.gradle.api.provider.Provider;
 import org.gradle.api.tasks.Input;
@@ -15,6 +17,7 @@ import org.gradle.api.tasks.TaskAction;
 import org.gradle.api.tasks.options.Option;
 
 public abstract class ReplFregeTask extends DefaultTask {
+    private static final Logger LOGGER         = Logging.getLogger(ReplFregeTask.class);
     public static final String REPL_MAIN_CLASS = "frege.repl.FregeRepl";
 
     @InputFile
@@ -26,6 +29,9 @@ public abstract class ReplFregeTask extends DefaultTask {
     @InputDirectory
     public abstract DirectoryProperty getFregeOutputDir();
 
+    @InputDirectory
+    public abstract DirectoryProperty getFregeMainSourceDir();
+
     @Input
     @Option(option     = "replModule",
            description = "The full name of the module which you want to load into the repl, e.g. 'my.mod.Name'")
@@ -39,30 +45,67 @@ public abstract class ReplFregeTask extends DefaultTask {
     }
 
     @Internal
-    public final Provider<FileTree> getClasspathWithoutReplClassFile()
+    public final Provider<FileTree> getReplClassFiles()
     {
         return getFregeOutputDir()
             .map(outDir -> outDir.getAsFileTree())
-            .map(tree   -> tree.matching(pattern -> pattern.exclude("**/*.java")))
-            .map(tree   -> tree.matching(pattern -> pattern.exclude(
-                String.format(
-                    "**/%s.class",
-                    getReplClassName().get()
+            .map(tree   -> tree.matching(
+                pattern -> pattern.include(
+                    String.format(
+                        "**/%s.class",
+                        getReplClassName().get()
+                    )
                 )
-            )));
+            ));
+    }
+
+    @Internal
+    public final Provider<FileTree> getReplJavaFiles()
+    {
+        return getFregeOutputDir()
+            .map(outDir -> outDir.getAsFileTree())
+            .map(tree   -> tree.matching(
+                pattern -> pattern.include(
+                    String.format(
+                        "**/%s.java",
+                        getReplClassName().get()
+                    )
+                ))
+            );
+    }
+
+    @Internal
+    public final Provider<FileTree> getReplFregeFile()
+    {
+        return getFregeMainSourceDir()
+            .map(outDir -> outDir.getAsFileTree())
+            .map(tree   -> tree.matching(
+                pattern -> pattern.include(
+                    String.format(
+                        "**/%s.fr",
+                        getReplClassName().get()
+                    )
+                ))
+            );
     }
 
     @TaskAction
-    public void printStartFregeReplCommand() {
-        System.out.println("Execute the following command to start the Frege Repl:");
-        System.out.println(String.format(
-            "java -cp %s %s",
+    public void printStartFregeReplCommand()
+    {
+        getProject().delete(getReplJavaFiles());
+        getProject().delete(getReplClassFiles());
+        LOGGER.lifecycle(
+            "Execute the following command to start the Frege Repl and load the Frege module:");
+        LOGGER.quiet(String.format(
+            "(echo :l %s && cat) | java -cp %s %s",
+            getReplFregeFile().get().getAsPath(),
             SharedTaskLogic.setupClasspath(
                 getProject(),
                 getFregeDependencies(),
                 getFregeCompilerJar(),
-                getClasspathWithoutReplClassFile())
+                getFregeOutputDir())
             .get().getAsPath(),
-            REPL_MAIN_CLASS));
+            REPL_MAIN_CLASS)
+        );
     }
 }