Provide fake ast classes for backwards compatibility

Author: otethal

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/modules/ast/AstModuleBuiltins.java

@@ -44,23 +44,27 @@
 import static com.oracle.graal.python.builtins.modules.BuiltinFunctions.CompileNode.PyCF_ONLY_AST;
 import static com.oracle.graal.python.builtins.modules.BuiltinFunctions.CompileNode.PyCF_TYPE_COMMENTS;
 import static com.oracle.graal.python.util.PythonUtils.EMPTY_OBJECT_ARRAY;
+import static com.oracle.graal.python.util.PythonUtils.toTruffleStringUncached;
 import static com.oracle.graal.python.util.PythonUtils.tsLiteral;
 
 import java.util.ArrayList;
 import java.util.List;
 
+import com.oracle.graal.python.PythonLanguage;
 import com.oracle.graal.python.builtins.CoreFunctions;
 import com.oracle.graal.python.builtins.Python3Core;
 import com.oracle.graal.python.builtins.PythonBuiltinClassType;
 import com.oracle.graal.python.builtins.PythonBuiltins;
 import com.oracle.graal.python.builtins.objects.module.PythonModule;
 import com.oracle.graal.python.builtins.objects.tuple.PTuple;
+import com.oracle.graal.python.builtins.objects.type.PythonAbstractClass;
 import com.oracle.graal.python.builtins.objects.type.PythonBuiltinClass;
 import com.oracle.graal.python.builtins.objects.type.PythonClass;
 import com.oracle.graal.python.nodes.attributes.ReadAttributeFromObjectNode;
 import com.oracle.graal.python.nodes.function.PythonBuiltinBaseNode;
 import com.oracle.graal.python.pegparser.sst.ModTy;
 import com.oracle.graal.python.runtime.PythonContext;
+import com.oracle.graal.python.runtime.object.PythonObjectFactory;
 import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
 import com.oracle.truffle.api.dsl.NodeFactory;
 import com.oracle.truffle.api.object.HiddenKey;
@@ -98,6 +102,32 @@ public void initialize(Python3Core core) {
         AstTypeFactory astTypeFactory = new AstTypeFactory(core.getLanguage(), core.factory(), astModule);
         AstState state = new AstState(astTypeFactory, core.lookupType(PythonBuiltinClassType.AST));
         astModule.setAttribute(AST_STATE_KEY, state);
+
+        createBackwardCompatibilityClasses(core, astModule, state);
+    }
+
+    private void createBackwardCompatibilityClasses(Python3Core core, PythonModule astModule, AstState state) {
+        // ast.py from cpython 3.10.5 defines classes for backwards compatibility
+        // As long as we are still using ast.py from 3.8.6, we need to provide these classes somehow.
+        PythonLanguage language = core.getLanguage();
+        PythonObjectFactory factory = core.factory();
+
+        makeType(language, factory, astModule, "Suite", state.clsModTy);
+
+        PythonClass slice_type = makeType(language, factory, astModule, "slice", state.clsAst);
+        makeType(language, factory, astModule, "ExtSlice", slice_type);
+        makeType(language, factory, astModule, "Index", slice_type);
+
+        makeType(language, factory, astModule, "AugLoad", state.clsExprContextTy);
+        makeType(language, factory, astModule, "AugStore", state.clsExprContextTy);
+        makeType(language, factory, astModule, "Param", state.clsExprContextTy);
+    }
+
+    private static PythonClass makeType(PythonLanguage language, PythonObjectFactory factory, PythonModule astModule, String name, PythonAbstractClass base) {
+        TruffleString tsName = toTruffleStringUncached(name);
+        PythonClass newType = factory.createPythonClassAndFixupSlots(language, PythonBuiltinClassType.PythonClass, tsName, new PythonAbstractClass[]{base});
+        astModule.setAttribute(tsName, newType);
+        return newType;
     }
 
     private static AstState getAstState(PythonContext context) {