Fix sys.getfilesystemencoding

Author: msimacek

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/modules/SysModuleBuiltins.java

@@ -51,6 +51,8 @@
 import java.util.Date;
 import java.util.List;
 
+import org.graalvm.nativeimage.ImageInfo;
+
 import com.oracle.graal.python.PythonLanguage;
 import com.oracle.graal.python.builtins.Builtin;
 import com.oracle.graal.python.builtins.CoreFunctions;
@@ -82,6 +84,7 @@
 import com.oracle.graal.python.runtime.PythonOptions;
 import com.oracle.graal.python.runtime.exception.PException;
 import com.oracle.graal.python.runtime.object.PythonObjectFactory;
+import com.oracle.graal.python.util.CharsetMapping;
 import com.oracle.graal.python.util.OverflowException;
 import com.oracle.graal.python.util.PythonUtils;
 import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
@@ -97,8 +100,6 @@
 import com.oracle.truffle.api.library.CachedLibrary;
 import com.oracle.truffle.api.profiles.ConditionProfile;
 
-import org.graalvm.nativeimage.ImageInfo;
-
 @CoreFunctions(defineModule = "sys")
 public class SysModuleBuiltins extends PythonBuiltins {
     private static final String LICENSE = "Copyright (c) Oracle and/or its affiliates. Licensed under the Universal Permissive License v 1.0 as shown at http://oss.oracle.com/licenses/upl.";
@@ -413,7 +414,10 @@ public abstract static class GetFileSystemEncodingNode extends PythonBuiltinNode
         @Specialization
         @TruffleBoundary
         protected String getFileSystemEncoding() {
-            return System.getProperty("file.encoding");
+            String javaEncoding = System.getProperty("file.encoding");
+            String pythonEncoding = CharsetMapping.getPythonEncodingNameFromJavaName(javaEncoding);
+            // Fallback on returning the property value if no mapping found
+            return pythonEncoding != null ? pythonEncoding : javaEncoding;
         }
     }
 

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/util/CharsetMapping.java

@@ -55,6 +55,7 @@
 public class CharsetMapping {
     private static final Map<String, Charset> JAVA_CHARSETS = new HashMap<>();
     private static final Map<String, String> CHARSET_NAME_MAP = new HashMap<>();
+    private static final Map<String, String> CHARSET_NAME_MAP_REVERSE = new HashMap<>();
 
     @TruffleBoundary
     public static Charset getCharset(String encoding) {
@@ -65,6 +66,11 @@ public static Charset getCharset(String encoding) {
         return null;
     }
 
+    @TruffleBoundary
+    public static String getPythonEncodingNameFromJavaName(String javaEncodingName) {
+        return CHARSET_NAME_MAP_REVERSE.get(javaEncodingName.toLowerCase());
+    }
+
     public static String normalize(String encoding) {
         return encoding.toLowerCase(Locale.ENGLISH).replaceAll("[^\\w.]+", "_");
     }
@@ -84,6 +90,9 @@ private static Charset getJavaCharset(String name) {
 
     private static void addMapping(String pythonName, String javaName) {
         CHARSET_NAME_MAP.put(normalize(pythonName), javaName);
+        if (javaName != null) {
+            CHARSET_NAME_MAP_REVERSE.put(javaName.toLowerCase(), pythonName.replace('_', '-'));
+        }
     }
 
     private static void addAlias(String alias, String pythonName) {