default to dont_write_bytecode and let the launcher set it to false

Author: timfel

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

@@ -51,9 +51,6 @@
 import java.util.Date;
 import java.util.List;
 
-import com.oracle.graal.python.util.OverflowException;
-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;
@@ -85,6 +82,7 @@
 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.OverflowException;
 import com.oracle.graal.python.util.PythonUtils;
 import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
 import com.oracle.truffle.api.Truffle;
@@ -99,6 +97,8 @@
 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.";
@@ -193,13 +193,13 @@ public void postInitialize(PythonCore core) {
             sys.setAttribute("executable", context.getOption(PythonOptions.Executable));
             sys.setAttribute("_base_executable", context.getOption(PythonOptions.Executable));
         }
-        sys.setAttribute("dont_write_bytecode", ImageInfo.inImageBuildtimeCode() || context.getOption(PythonOptions.DontWriteBytecodeFlag));
+        sys.setAttribute("dont_write_bytecode", context.getOption(PythonOptions.DontWriteBytecodeFlag));
         String pycachePrefix = context.getOption(PythonOptions.PyCachePrefix);
         sys.setAttribute("pycache_prefix", pycachePrefix.isEmpty() ? PNone.NONE : pycachePrefix);
         sys.setAttribute("__flags__", core.factory().createTuple(new Object[]{
                         false, // bytes_warning
                         !context.getOption(PythonOptions.PythonOptimizeFlag), // debug
-                        ImageInfo.inImageBuildtimeCode() || context.getOption(PythonOptions.DontWriteBytecodeFlag),  // dont_write_bytecode
+                        context.getOption(PythonOptions.DontWriteBytecodeFlag),  // dont_write_bytecode
                         false, // hash_randomization
                         context.getOption(PythonOptions.IgnoreEnvironmentFlag), // ignore_environment
                         context.getOption(PythonOptions.InspectFlag), // inspect

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/runtime/PythonOptions.java

@@ -107,7 +107,7 @@ private PythonOptions() {
     public static final OptionKey<Boolean> IsolateFlag = new OptionKey<>(false);
 
     @Option(category = OptionCategory.USER, help = "Equivalent to the Python -B flag. Don't write bytecode files.", stability = OptionStability.STABLE) //
-    public static final OptionKey<Boolean> DontWriteBytecodeFlag = new OptionKey<>(false);
+    public static final OptionKey<Boolean> DontWriteBytecodeFlag = new OptionKey<>(true);
 
     @Option(category = OptionCategory.USER, help = "If this is set, GraalPython will write .pyc files in a mirror directory tree at this path, " +
                     "instead of in __pycache__ directories within the source tree. " +