implement #112 - Init __file__ in JSR223 bindings for Jython

Author: Gubaer

.gitignore

@@ -24,3 +24,4 @@ software
 package.json
 releases.generated.yml
 set-env.ps1
+.jython_cache

build.gradle

@@ -45,7 +45,7 @@ dependencies {
     testImplementation group: 'org.apache.groovy', name: 'groovy-test', version: project.property('dep.groovy')
 
     testRuntimeOnly group: 'org.junit.jupiter', name: 'junit-jupiter-engine', version: project.property('dep.jupiter')
-    testRuntimeOnly group: "org.python", name: "jython", version: "2.7.3"
+    testRuntimeOnly group: "org.python", name: "jython", version: "2.7.4"
 
     testRuntimeOnly 'org.junit.platform:junit-platform-launcher'
 }
@@ -289,9 +289,9 @@ tasks.register('testWithGraalVMJDK', Test) {
 tasks.register('testJSR223EnginePresent', Test) {
     useJUnitPlatform()
     jvmArgs JVM_ARGS
-    // groovy and python are on the classpath
+    systemProperty "python.import.site", false
     scanForTestClasses = false
-    include "org/openstreetmap/josm/plugins/scripting/jsr223/JSR223CompatibleEnginePresentTest.class"
+    include "org/openstreetmap/josm/plugins/scripting/jsr223/*.class"
     testLogging {
         events TestLogEvent.FAILED, TestLogEvent.PASSED
         exceptionFormat = TestExceptionFormat.FULL

src/main/java/org/openstreetmap/josm/plugins/scripting/model/ScriptEngineDescriptor.java

@@ -393,6 +393,15 @@ public boolean isDescribingGraalJS() {
         return this.engineType.equals(ScriptEngineType.GRAALVM) && "js".equals(this.engineId);
     }
 
+    /**
+     * Replies true if this descriptor describes the JSR223-compatible Jython-engine
+     *
+     * @return true if this descriptor describes the JSR223-compatible Jython-engine
+     */
+    public boolean isJython() {
+        return contentMimeTypes.contains("text/python");
+    }
+
     public enum ScriptEngineType {
         /**
          * a scripting engine supplied as JSR233 compliant scripting engine

src/main/java/org/openstreetmap/josm/plugins/scripting/ui/ScriptExecutor.java

@@ -86,31 +86,35 @@ private void warnOpenScriptFileFailed(File f, Exception e) {
      * @throws NullPointerException     if <code>scriptFile</code> is null
      * @throws IllegalArgumentException if <code>scriptFile</code> isn't a readable file
      */
-    void runScriptWithPluggedEngine(
+    public void runScriptWithPluggedEngine(
             @NotNull final ScriptEngineDescriptor desc,
             @NotNull final File scriptFile) throws IllegalArgumentException {
         Objects.requireNonNull(desc);
         Objects.requireNonNull(scriptFile);
         Assert.assertArg(scriptFile.isFile(), "Expected a script file, got ''{0}''", scriptFile);
         Assert.assertArg(scriptFile.canRead(), "Expected a readable script file, got ''{0}''", scriptFile);
 
-        logger.info(format(""));
-
         final ScriptEngine engine = JSR223ScriptEngineProvider.getInstance().getScriptEngine(desc);
         if (engine == null) {
             warnScriptingEngineNotFound();
             return;
         }
         final Runnable task = () -> {
+            final var bindings = engine.createBindings();
+            // For a python script we initialize the bindings as follows:
+            //    __file__ = <full path to script file>
+            if (desc.isJython()) {
+                bindings.put("__file__", scriptFile.getPath());
+            }
             try {
                 if (engine instanceof Compilable) {
                     JSR223CompiledScriptCache
                         .getInstance()
                         .compile((Compilable) engine, scriptFile)
-                        .eval();
+                        .eval(bindings);
                 } else {
                     try (var reader = new InputStreamReader(new FileInputStream(scriptFile), StandardCharsets.UTF_8)) {
-                        engine.eval(reader);
+                        engine.eval(reader, bindings);
                     }
                 }
             } catch (ScriptException e) {

src/test/unit/groovy/org/openstreetmap/josm/plugins/scripting/jsr223/JythonBindingsTest.groovy

@@ -0,0 +1,35 @@
+package org.openstreetmap.josm.plugins.scripting.jsr223
+
+import org.junit.jupiter.api.Test
+import org.openstreetmap.josm.gui.MainApplication
+import org.openstreetmap.josm.plugins.scripting.JOSMFixtureBasedTest
+import org.openstreetmap.josm.plugins.scripting.model.ScriptEngineMetaDataProvider
+import org.openstreetmap.josm.plugins.scripting.ui.ScriptExecutor
+
+import static org.junit.Assert.assertEquals
+
+class JythonBindingsTest extends JOSMFixtureBasedTest {
+
+    public static String __file__holder = null
+
+    @Test
+    void ensureDefaultBindingsAreSet() {
+        final jythonDesc = ScriptEngineMetaDataProvider
+            .getAvailablePluggedScriptEngines()
+            .filter(desc -> desc.isJython())
+            .findAny()
+            .orElseThrow(() -> new IllegalStateException("No Jython scripting engine found"))
+
+        final executor = new ScriptExecutor(MainApplication.getMainFrame())
+
+        // generate temporary script file
+        final scriptFile = File.createTempFile("test-script", "")
+        scriptFile.write("""
+from org.openstreetmap.josm.plugins.scripting.jsr223 import JythonBindingsTest
+JythonBindingsTest.__file__holder = __file__
+        """)
+        executor.runScriptWithPluggedEngine(jythonDesc, scriptFile)
+        assertEquals(scriptFile.getPath(), __file__holder)
+        scriptFile.delete()
+    }
+}