When Blender is built against a debug Python library the following steps cause a negative reference count and asserts.
This can be redone with the following steps:
- Run Blender with factory settings.
- Press W once (to set the circle select tool).
- Ctrl-N, Enter (to make a new file).
Blender exits with the following error.
source/blender/python/intern/bpy_rna_callback.c:267: _Py_NegativeRefcount: Assertion failed: object has negative ref count Enable tracemalloc to get the memory block allocation traceback object address : 0x7fda4ad5dcc0 object refcount : -1 object type : 0x55a5d0f754a0 object type name: tuple object repr : <refcnt -1 at 0x7fda4ad5dcc0> Fatal Python error: _PyObject_AssertFailed: _PyObject_AssertFailed Python runtime state: initialized Current thread 0x00007fda712548c0 (most recent call first): File "/src/cmake_debug/bin/3.1/scripts/startup/bl_ui/space_toolsystem_common.py", line 1073 in _activate_by_item File "/src/cmake_debug/bin/3.1/scripts/startup/bl_ui/space_toolsystem_common.py", line 1091 in activate_by_id File "/src/cmake_debug/bin/3.1/scripts/startup/bl_operators/wm.py", line 2119 in execute Extension modules: bpy.props, bpy.app.icons, bpy.app.timers, bpy.utils.units, bpy.types, mathutils.geometry, mathutils.interpolate, mathutils.noise, mathutils, idprop, gpu.capabilities, gpu.matrix, gpu.platform, gpu.select, gpu.shader, gpu.state, gpu.texture (total: 17)
Reporting this for reference.