Further thread safety changes for Python 3.13 free threading

See #1683

panda/src/collide/collisionPolygon_ext.cxx

@@ -72,6 +72,9 @@ convert_points(pvector<LPoint3> &vec, PyObject *points) {
     return false;
   }
 
+  bool success = true;
+
+  Py_BEGIN_CRITICAL_SECTION(seq);
   PyObject **items = PySequence_Fast_ITEMS(seq);
   Py_ssize_t len = PySequence_Fast_GET_SIZE(seq);
   void *ptr;
@@ -90,13 +93,14 @@ convert_points(pvector<LPoint3> &vec, PyObject *points) {
     }
     else {
       Dtool_Raise_TypeError("Argument must be of LPoint3 type.");
-      Py_DECREF(seq);
-      return false;
+      success = false;
+      break;
     }
   }
 
+  Py_END_CRITICAL_SECTION();
   Py_DECREF(seq);
-  return true;
+  return success;
 }
 
 #endif

panda/src/express/pointerToArray_ext.I

@@ -106,12 +106,13 @@ __init__(PyObject *self, PyObject *source) {
   // We need to initialize the this pointer before we can call push_back.
   DtoolInstance_INIT_PTR(self, this->_this);
 
+  Py_BEGIN_CRITICAL_SECTION(source);
   Py_ssize_t size = PySequence_Size(source);
   this->_this->reserve(size);
   for (Py_ssize_t i = 0; i < size; ++i) {
     PyObject *item = PySequence_GetItem(source, i);
     if (item == nullptr) {
-      return;
+      break;
     }
     PyObject *result = PyObject_CallFunctionObjArgs(push_back, self, item, nullptr);
     Py_DECREF(item);
@@ -121,10 +122,11 @@ __init__(PyObject *self, PyObject *source) {
       PyErr_Format(PyExc_TypeError,
                    "Element %zd in sequence passed to PointerToArray "
                    "constructor could not be added", i);
-      return;
+      break;
     }
     Py_DECREF(result);
   }
+  Py_END_CRITICAL_SECTION();
 }
 
 /**

panda/src/gobj/textureCollection_ext.cxx

@@ -31,13 +31,14 @@ __init__(PyObject *self, PyObject *sequence) {
     return;
   }
 
+  Py_BEGIN_CRITICAL_SECTION(fast);
   Py_ssize_t size = PySequence_Fast_GET_SIZE(fast);
   _this->reserve(size);
 
   for (int i = 0; i < size; ++i) {
     PyObject *item = PySequence_Fast_GET_ITEM(fast, i);
     if (item == nullptr) {
-      return;
+      break;
     }
 
     Texture *tex;
@@ -48,13 +49,12 @@ __init__(PyObject *self, PyObject *sequence) {
       stream << "Element " << i << " in sequence passed to TextureCollection constructor is not a Texture";
       std::string str = stream.str();
       PyErr_SetString(PyExc_TypeError, str.c_str());
-      Py_DECREF(fast);
-      return;
+      break;
     } else {
       _this->add_texture(tex);
     }
   }
-
+  Py_END_CRITICAL_SECTION();
   Py_DECREF(fast);
 }
 

panda/src/pgraph/nodePathCollection_ext.cxx

@@ -36,13 +36,14 @@ __init__(PyObject *self, PyObject *sequence) {
     return;
   }
 
+  Py_BEGIN_CRITICAL_SECTION(fast);
   Py_ssize_t size = PySequence_Fast_GET_SIZE(fast);
   _this->reserve(size);
 
   for (int i = 0; i < size; ++i) {
     PyObject *item = PySequence_Fast_GET_ITEM(fast, i);
     if (item == nullptr) {
-      return;
+      break;
     }
 
     NodePath *path;
@@ -52,13 +53,12 @@ __init__(PyObject *self, PyObject *sequence) {
       stream << "Element " << i << " in sequence passed to NodePathCollection constructor is not a NodePath";
       std::string str = stream.str();
       PyErr_SetString(PyExc_TypeError, str.c_str());
-      Py_DECREF(fast);
-      return;
+      break;
     } else {
       _this->add_path(*path);
     }
   }
-
+  Py_END_CRITICAL_SECTION();
   Py_DECREF(fast);
 }
 

panda/src/pgraph/pythonLoaderFileType.cxx

@@ -89,26 +89,25 @@ init(PyObject *loader) {
       return false;
     }
 
-    PyObject *sequence = PySequence_Fast(extensions, "extensions must be a sequence");
-    PyObject **items = PySequence_Fast_ITEMS(sequence);
-    Py_ssize_t num_items = PySequence_Fast_GET_SIZE(sequence);
+    PyObject *tuple = PySequence_Tuple(extensions);
+    Py_ssize_t num_items = PyTuple_GET_SIZE(tuple);
     Py_DECREF(extensions);
 
     if (num_items == 0) {
       PyErr_SetString(PyExc_ValueError, "extensions list may not be empty");
-      Py_DECREF(sequence);
+      Py_DECREF(tuple);
       return false;
     }
 
     bool found_extension = false;
 
     for (Py_ssize_t i = 0; i < num_items; ++i) {
-      PyObject *extension = items[i];
+      PyObject *extension = PyTuple_GET_ITEM(tuple, i);
       const char *extension_str;
       Py_ssize_t extension_len;
       extension_str = PyUnicode_AsUTF8AndSize(extension, &extension_len);
       if (extension_str == nullptr) {
-        Py_DECREF(sequence);
+        Py_DECREF(tuple);
         return false;
       }
 
@@ -127,7 +126,7 @@ init(PyObject *loader) {
         }
       }
     }
-    Py_DECREF(sequence);
+    Py_DECREF(tuple);
 
     if (!found_extension) {
       PyObject *repr = PyObject_Repr(loader);

panda/src/pgraph/shaderInput_ext.cxx

@@ -269,12 +269,20 @@ __init__(CPT_InternalName name, PyObject *value, int priority) {
 
   } else if (PySequence_Check(value) && !PyUnicode_CheckExact(value)) {
     // Iterate over the sequence to make sure all have the same type.
+#ifdef Py_GIL_DISABLED
+    PyObject *fast = PySequence_Tuple(value);
+#else
     PyObject *fast = PySequence_Fast(value, "unknown type passed to ShaderInput");
+#endif
     if (fast == nullptr) {
       return;
     }
 
+#ifdef Py_GIL_DISABLED
+    Py_ssize_t num_items = PyTuple_GET_SIZE(fast);
+#else
     Py_ssize_t num_items = PySequence_Fast_GET_SIZE(fast);
+#endif
     if (num_items <= 0) {
       // We can't determine the type of a list of size 0.
       _this->_type = ShaderInput::M_numeric;
@@ -289,6 +297,9 @@ __init__(CPT_InternalName name, PyObject *value, int priority) {
     for (Py_ssize_t i = 0; i < num_items; ++i) {
       PyObject *item = items[i];
 
+      //FIXME: if these items are not tuples, this is not thread-safe in the
+      // free-threaded build.  Convert everything to tuples, and push to a
+      // vector?
       if (PySequence_Check(item)) {
         Py_ssize_t itemsize = PySequence_Size(item);
         if (known_itemsize >= 0 && itemsize != known_itemsize) {
@@ -310,7 +321,7 @@ __init__(CPT_InternalName name, PyObject *value, int priority) {
             Dtool_Raise_TypeError("unknown element type in sequence passed as element of sequence passed to ShaderInput");
             Py_DECREF(subitem);
             Py_DECREF(fast);
-            break;
+            return;
           }
           Py_DECREF(subitem);
         }

panda/src/putil/typedWritable_ext.cxx

@@ -349,17 +349,24 @@ find_global_decode(PyObject *this_class, const char *func_name) {
 
   PyObject *bases = PyObject_GetAttrString(this_class, "__bases__");
   if (bases != nullptr) {
-    if (PySequence_Check(bases)) {
-      Py_ssize_t size = PySequence_Size(bases);
-      for (Py_ssize_t i = 0; i < size; ++i) {
-        PyObject *base = PySequence_GetItem(bases, i);
-        if (base != nullptr) {
-          PyObject *func = find_global_decode(base, func_name);
-          Py_DECREF(base);
-          if (func != nullptr) {
-            Py_DECREF(bases);
-            return func;
-          }
+    {
+      PyObject *tuple = PySequence_Tuple(bases);
+      Py_DECREF(bases);
+      if (tuple == nullptr) {
+        PyErr_Clear();
+        return nullptr;
+      }
+      bases = tuple;
+    }
+
+    Py_ssize_t size = PyTuple_GET_SIZE(bases);
+    for (Py_ssize_t i = 0; i < size; ++i) {
+      PyObject *base = PyTuple_GET_ITEM(bases, i);
+      if (base != nullptr) {
+        PyObject *func = find_global_decode(base, func_name);
+        if (func != nullptr) {
+          Py_DECREF(bases);
+          return func;
         }
       }
     }