PyAPI: include the property name & type in registration errors

This gives useful context in errors,
also remove newline endings from exceptions.

2 files changed, 23 insertions, 9 deletions

diff --git a/source/blender/python/intern/bpy_props.h b/source/blender/python/intern/bpy_props.h
index bc7f0cfe416..e6bbd6f708d 100644
--- a/source/blender/python/intern/bpy_props.h
+++ b/source/blender/python/intern/bpy_props.h
@@ -33,7 +33,10 @@ StructRNA *pointer_type_from_py(PyObject *value, const char *error_prefix);
 
 typedef struct {
   PyObject_HEAD
-  /* This isn't GC tracked, it's a function from `bpy.props` so it's not going away. */
+  /**
+   * Internally a #PyCFunctionObject type.
+   * \note This isn't GC tracked, it's a function from `bpy.props` so it's not going away.
+   */
   void *fn;
   PyObject *kw;
 } BPy_PropDeferred;
diff --git a/source/blender/python/intern/bpy_rna.c b/source/blender/python/intern/bpy_rna.c
index 759630b73ac..dff96f74d62 100644
--- a/source/blender/python/intern/bpy_rna.c
+++ b/source/blender/python/intern/bpy_rna.c
@@ -8040,14 +8040,21 @@ static int deferred_register_prop(StructRNA *srna, PyObject *key, PyObject *item
   PyObject *py_kw = ((BPy_PropDeferred *)item)->kw;
   PyObject *py_srna_cobject, *py_ret;
 
+  /* Show the function name in errors to help give context. */
+  BLI_assert(PyCFunction_CheckExact(py_func));
+  PyMethodDef *py_func_method_def = ((PyCFunctionObject *)py_func)->m_ml;
+  const char *func_name = py_func_method_def->ml_name;
+
   PyObject *args_fake;
+  const char *key_str = PyUnicode_AsUTF8(key);
 
-  if (*PyUnicode_AsUTF8(key) == '_') {
+  if (*key_str == '_') {
     PyErr_Format(PyExc_ValueError,
                  "bpy_struct \"%.200s\" registration error: "
-                 "%.200s could not register because the property starts with an '_'\n",
+                 "'%.200s' %.200s could not register because it starts with an '_'",
                  RNA_struct_identifier(srna),
-                 PyUnicode_AsUTF8(key));
+                 key_str,
+                 func_name);
     return -1;
   }
   py_srna_cobject = PyCapsule_New(srna, NULL, NULL);
@@ -8066,8 +8073,12 @@ static int deferred_register_prop(StructRNA *srna, PyObject *key, PyObject *item
          *(PyCFunctionWithKeywords)PyCFunction_GET_FUNCTION(py_func) == BPy_CollectionProperty) &&
         RNA_struct_idprops_contains_datablock(type_srna)) {
       PyErr_Format(PyExc_ValueError,
-                   "bpy_struct \"%.200s\" doesn't support datablock properties\n",
-                   RNA_struct_identifier(srna));
+                   "bpy_struct \"%.200s\" registration error: "
+                   "'%.200s' %.200s could not register because "
+                   "this type doesn't support data-block properties",
+                   RNA_struct_identifier(srna),
+                   key_str,
+                   func_name);
       return -1;
     }
   }
@@ -8085,12 +8096,12 @@ static int deferred_register_prop(StructRNA *srna, PyObject *key, PyObject *item
 
     Py_DECREF(args_fake); /* Free's py_srna_cobject too. */
 
-    // PyC_LineSpit();
     PyErr_Format(PyExc_ValueError,
                  "bpy_struct \"%.200s\" registration error: "
-                 "%.200s could not register\n",
+                 "'%.200s' %.200s could not register (see previous error)",
                  RNA_struct_identifier(srna),
-                 PyUnicode_AsUTF8(key));
+                 key_str,
+                 func_name);
     return -1;
   }