Fix DirEntry.stat

The attribute was not writable, it was missing follow_symlinks and its
return value was tuple instead of stat_result.

Author: msimacek

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/posix/DirEntryBuiltins.java

@@ -52,8 +52,6 @@
 import com.oracle.graal.python.builtins.objects.function.PArguments;
 import com.oracle.graal.python.builtins.objects.object.PythonObjectLibrary;
 import com.oracle.graal.python.nodes.SpecialMethodNames;
-import com.oracle.graal.python.nodes.attributes.ReadAttributeFromObjectNode;
-import com.oracle.graal.python.nodes.attributes.WriteAttributeToObjectNode;
 import com.oracle.graal.python.nodes.function.PythonBuiltinBaseNode;
 import com.oracle.graal.python.nodes.function.builtins.PythonBinaryBuiltinNode;
 import com.oracle.graal.python.nodes.function.builtins.PythonUnaryBuiltinNode;
@@ -150,22 +148,19 @@ boolean test(PDirEntry self) {
         }
     }
 
-    @Builtin(name = "stat", minNumOfPositionalArgs = 1, doc = "return stat_result object for the entry; cached per entry")
+    @Builtin(name = "stat", minNumOfPositionalArgs = 1, parameterNames = {"$self", "follow_symlinks"}, doc = "return stat_result object for the entry; cached per entry")
     @GenerateNodeFactory
-    abstract static class StatNode extends PythonUnaryBuiltinNode {
-        private static final String STAT_RESULT = "__stat_result__";
+    abstract static class StatNode extends PythonBinaryBuiltinNode {
 
         @Specialization
-        Object test(VirtualFrame frame, PDirEntry self,
-                        @Cached("create()") ReadAttributeFromObjectNode readNode,
-                        @Cached("create()") WriteAttributeToObjectNode writeNode,
+        Object test(VirtualFrame frame, PDirEntry self, Object followSymlinks,
                         @Cached("create()") PosixModuleBuiltins.StatNode statNode) {
-            Object stat_result = readNode.execute(self, STAT_RESULT);
-            if (stat_result == PNone.NO_VALUE) {
-                stat_result = statNode.execute(frame, self.getFile().getAbsoluteFile().getPath(), PNone.NO_VALUE);
-                writeNode.execute(self, STAT_RESULT, stat_result);
+            Object statResult = self.getCachedStatResult();
+            if (statResult == null) {
+                statResult = statNode.execute(frame, self.getFile().getAbsoluteFile().getPath(), followSymlinks);
+                self.setCachedStatResult(statResult);
             }
-            return stat_result;
+            return statResult;
         }
     }
 

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/posix/PDirEntry.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2020, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * The Universal Permissive License (UPL), Version 1.0
@@ -47,6 +47,7 @@
 public class PDirEntry extends PythonBuiltinObject {
     private final TruffleFile file;
     private final String name;
+    private Object cachedStatResult;
 
     public PDirEntry(LazyPythonClass cls, String name, TruffleFile file) {
         super(cls);
@@ -61,4 +62,12 @@ public TruffleFile getFile() {
     public String getName() {
         return name;
     }
+
+    public Object getCachedStatResult() {
+        return cachedStatResult;
+    }
+
+    public void setCachedStatResult(Object cachedStatResult) {
+        this.cachedStatResult = cachedStatResult;
+    }
 }

graalpython/lib-graalpython/posix.py

@@ -1,4 +1,4 @@
-# Copyright (c) 2018, 2019, Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 2018, 2020, Oracle and/or its affiliates. All rights reserved.
 # DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 #
 # The Universal Permissive License (UPL), Version 1.0
@@ -56,6 +56,12 @@ def stat(filename, follow_symlinks=True):
     return stat_result(old_stat(filename, follow_symlinks=follow_symlinks))
 
 
+__dir_entry_old_stat = DirEntry.stat
+def __dir_entry_stat(self, follow_symlinks=True):
+    return stat_result(__dir_entry_old_stat(self, follow_symlinks=follow_symlinks))
+DirEntry.stat = __dir_entry_stat
+
+
 @__builtin__
 def lstat(filename):
     if not graal_python_is_native: