copy JYTHONPATH to sys.path in Jython engine

extends feature request #112

Author: Gubaer

build.gradle

@@ -290,6 +290,7 @@ tasks.register('testJSR223EnginePresent', Test) {
     useJUnitPlatform()
     jvmArgs JVM_ARGS
     systemProperty "python.import.site", false
+    environment "JYTHONPATH", ["/foo/bar/jythonpath1", "/foo/bar/jythonpath2"].join(File.pathSeparator)
     scanForTestClasses = false
     include "org/openstreetmap/josm/plugins/scripting/jsr223/*.class"
     testLogging {

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

@@ -19,9 +19,11 @@
 import java.awt.*;
 import java.io.*;
 import java.nio.charset.StandardCharsets;
+import java.util.Arrays;
 import java.util.Objects;
 import java.util.logging.Level;
 import java.util.logging.Logger;
+import java.util.stream.Collectors;
 
 import static org.openstreetmap.josm.plugins.scripting.ui.SwingUtil.runOnSwingEDT;
 import static org.openstreetmap.josm.tools.I18n.tr;
@@ -101,17 +103,36 @@ public void runScriptWithPluggedEngine(
         }
         final Runnable task = () -> {
             final var bindings = engine.createBindings();
-            // For a python script we initialize the bindings as follows:
-            //    __file__ = <full path to script file>
-            //    add the script's parent directory to sys.path
             if (desc.isJython()) {
+                // For a python script we initialize the bindings as follows:
+                //    __file__ = <full path to script file>
                 bindings.put("__file__", scriptFile.getPath());
+
+                // For a python script we initialize the Jython engine as follows:
+                //    add the script's parent directory to sys.path
+                //    add the paths in JYTHONPATH to sys.path
                 final var sysPathStatement = format("import sys; sys.path.append(''{0}'')", scriptFile.getParent());
                 try {
                     engine.eval(sysPathStatement);
                 } catch(ScriptException e) {
                     logger.log(Level.WARNING, format("Failed to add ''{0}'' to sys.path", scriptFile.getParent()), e);
                 }
+                final var jythonPath = System.getenv("JYTHONPATH");
+                if (jythonPath != null) {
+                    final var paths = jythonPath.split(File.pathSeparator);
+                    if (paths.length > 0) {
+                        final var script = "import sys; " +
+                            Arrays.stream(paths)
+                                .distinct()
+                                .map(path -> format("sys.path.append(''{0}'')", path))
+                                .collect(Collectors.joining("; "));
+                        try {
+                            engine.eval(script);
+                        } catch(ScriptException e) {
+                            logger.log(Level.WARNING, format("Failed to add JYTHONPATH ''{0}'' to sys.path", jythonPath), e);
+                        }
+                    }
+                }
             }
             try {
                 if (engine instanceof Compilable) {

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

@@ -14,14 +14,19 @@ class JythonBindingsTest extends JOSMFixtureBasedTest {
     public static String __file__holder = null
     public static boolean scriptPathInSysPath = false
     public static int sum = 0
+    public static boolean jythonPathInSysPath = true
 
-    @Test
-    void ensure__file__IsSet() {
-        final jythonDesc = ScriptEngineMetaDataProvider
+    static def getJythonDescriptor() {
+        return  ScriptEngineMetaDataProvider
             .getAvailablePluggedScriptEngines()
             .filter(desc -> desc.isJython())
             .findAny()
             .orElseThrow(() -> new IllegalStateException("No Jython scripting engine found"))
+    }
+
+    @Test
+    void ensure__file__IsSet() {
+        final jythonDesc = jythonDescriptor
 
         final executor = new ScriptExecutor(MainApplication.getMainFrame())
 
@@ -38,11 +43,7 @@ JythonBindingsTest.__file__holder = __file__
 
     @Test
     void ensureSysPathIsSet() {
-        final jythonDesc = ScriptEngineMetaDataProvider
-                .getAvailablePluggedScriptEngines()
-                .filter(desc -> desc.isJython())
-                .findAny()
-                .orElseThrow(() -> new IllegalStateException("No Jython scripting engine found"))
+        final jythonDesc = jythonDescriptor
 
         final executor = new ScriptExecutor(MainApplication.getMainFrame())
 
@@ -62,11 +63,7 @@ for path in sys.path:
 
     @Test
     void ensureImportFromSysPathWorks() {
-        final jythonDesc = ScriptEngineMetaDataProvider
-                .getAvailablePluggedScriptEngines()
-                .filter(desc -> desc.isJython())
-                .findAny()
-                .orElseThrow(() -> new IllegalStateException("No Jython scripting engine found"))
+        final jythonDesc = jythonDescriptor
 
         final executor = new ScriptExecutor(MainApplication.getMainFrame())
 
@@ -91,4 +88,30 @@ JythonBindingsTest.sum = add(5,3)
         moduleFile.delete()
 
     }
+
+    @Test
+    void ensureJYTHONPATHinSysPath() {
+        final jythonDesc = jythonDescriptor
+
+        final executor = new ScriptExecutor(MainApplication.getMainFrame())
+
+        // generate temporary script file
+        final scriptFile = File.createTempFile("test-script", "")
+        scriptFile.write("""
+import sys
+from java.lang import System
+from java.io import File
+from org.openstreetmap.josm.plugins.scripting.jsr223 import JythonBindingsTest
+jythonpath = System.getenv('JYTHONPATH')
+if jythonpath:
+    paths = jythonpath.split(File.pathSeparator)
+    result = True 
+    for path in paths:
+        result = result and path in sys.path
+    JythonBindingsTest.jythonPathInSysPath = result    
+        """)
+        executor.runScriptWithPluggedEngine(jythonDesc, scriptFile)
+        assertTrue(jythonPathInSysPath)
+        scriptFile.delete()
+    }
 }