fix starting multiple threads again

Author: timfel

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/PythonLanguage.java

@@ -127,6 +127,13 @@ public final class PythonLanguage extends TruffleLanguage<PythonContext> {
 
     private static final Object[] CONTEXT_INSENSITIVE_SINGLETONS = new Object[]{PNone.NONE, PNone.NO_VALUE, PEllipsis.INSTANCE, PNotImplemented.NOT_IMPLEMENTED};
 
+    /*
+     * We need to store this here, because the check is on the language and can
+     * come from a thread that has no context, but we enable or disable threads
+     * with a context option. So we store this here when a context is created.
+     */
+    private Boolean isWithThread = null;
+
     public static int getNumberOfSpecialSingletons() {
         return CONTEXT_INSENSITIVE_SINGLETONS.length;
     }
@@ -159,14 +166,14 @@ protected void finalizeContext(PythonContext context) {
     protected boolean areOptionsCompatible(OptionValues firstOptions, OptionValues newOptions) {
         // internal sources were marked during context initialization
         return (firstOptions.get(PythonOptions.ExposeInternalSources).equals(newOptions.get(PythonOptions.ExposeInternalSources)) &&
+                        // we cache WithThread on the lanugage
+                        firstOptions.get(PythonOptions.WithThread).equals(newOptions.get(PythonOptions.WithThread)) &&
                         // we cache CatchAllExceptions hard on TryExceptNode
                         firstOptions.get(PythonOptions.CatchAllExceptions).equals(newOptions.get(PythonOptions.CatchAllExceptions)));
     }
 
     private boolean areOptionsCompatibleWithPreinitializedContext(OptionValues firstOptions, OptionValues newOptions) {
         return (areOptionsCompatible(firstOptions, newOptions) &&
-                        // we cache WithThread in SysConfigModuleBuiltins
-                        firstOptions.get(PythonOptions.WithThread).equals(newOptions.get(PythonOptions.WithThread)) &&
                         // disabling TRegex has an effect on the _sre Python functions that are
                         // dynamically created
                         firstOptions.get(PythonOptions.WithTRegex).equals(newOptions.get(PythonOptions.WithTRegex)));
@@ -186,6 +193,8 @@ protected boolean patchContext(PythonContext context, Env newEnv) {
 
     @Override
     protected PythonContext createContext(Env env) {
+        assert this.isWithThread == null || this.isWithThread == PythonOptions.isWithThread() : "conflicting thread options in the same language!";
+        this.isWithThread = PythonOptions.isWithThread(env);
         ensureHomeInOptions(env);
         Python3Core newCore = new Python3Core(new PythonParserImpl());
         return new PythonContext(this, env, newCore);
@@ -614,7 +623,7 @@ protected boolean isThreadAccessAllowed(Thread thread, boolean singleThreaded) {
         if (singleThreaded) {
             return super.isThreadAccessAllowed(thread, singleThreaded);
         }
-        return PythonOptions.isWithThread();
+        return isWithThread;
     }
 
     @Override

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

@@ -28,6 +28,7 @@
 import com.oracle.graal.python.PythonLanguage;
 import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
 import com.oracle.truffle.api.Option;
+import com.oracle.truffle.api.TruffleLanguage.Env;
 
 import org.graalvm.options.OptionCategory;
 import org.graalvm.options.OptionDescriptors;
@@ -162,6 +163,11 @@ public static <T> T getOption(PythonContext context, OptionKey<T> key) {
         return context.getOptions().get(key);
     }
 
+    @TruffleBoundary
+    public static <T> T getOption(Env env, OptionKey<T> key) {
+        return env.getOptions().get(key);
+    }
+
     @TruffleBoundary
     public static int getIntOption(PythonContext context, OptionKey<Integer> key) {
         if (context == null) {
@@ -202,6 +208,10 @@ public static boolean isWithThread() {
         return getOption(PythonLanguage.getContextRef().get(), WithThread);
     }
 
+    public static boolean isWithThread(Env env) {
+        return getOption(env, WithThread);
+    }
+
     public static boolean getEnableForcedSplits() {
         return getOption(PythonLanguage.getContextRef().get(), EnableForcedSplits);
     }

graalpython/lib-graalpython/_thread.py

@@ -55,10 +55,10 @@ def _set_sentinel():
 
 
 def load():
-    import sys
-    filename = sys.graal_python_stdlib_home + ("/_dummy_thread.py")
-    _dummy_thread = __import__(filename, "_thread")
     if not _sysconfig.get_config_vars().get('WITH_THREAD'):
+        import sys
+        filename = sys.graal_python_stdlib_home + ("/_dummy_thread.py")
+        _dummy_thread = __import__(filename, "_thread")
         sys.modules["_thread"] = _dummy_thread
 load()
 del load