loading after saving lazyconfig throws an error No module named 'detectron2._cfg_loader1c03'

[darwinharianto]

Instructions To Reproduce the 🐛 Bug:

1. Full runnable code or full changes you made:

from detectron2.config import LazyConfig from detectron2 import model_zoo from detectron2.config import LazyConfig, instantiate

model_name="new_baselines/mask_rcnn_regnetx_4gf_dds_FPN_100ep_LSJ.py"

cfg = LazyConfig.load(model_zoo.get_config_file(model_name)) dump_cfg_path = f'./test_conf.yaml' LazyConfig.save(cfg, dump_cfg_path) args = LazyConfig.load(dump_cfg_path)

2. What exact command you run:
Running above script
3. __Full logs__ or other relevant observations:

Traceback (most recent call last): File "~/lib/python3.7/site-packages/yaml/constructor.py", line 532, in find_python_name import(module_name) ModuleNotFoundError: No module named 'detectron2._cfg_loader1c03'

During handling of the above exception, another exception occurred:

Traceback (most recent call last): File "front_end/test.py", line 12, in args = LazyConfig.load(dump_cfg_path) File "~/lib/python3.7/site-packages/detectron2/config/lazy.py", line 207, in load obj = yaml.unsafe_load(f) File "~/lib/python3.7/site-packages/yaml/init.py", line 182, in unsafe_load return load(stream, UnsafeLoader) File "~/lib/python3.7/site-packages/yaml/init.py", line 114, in load return loader.get_single_data() File "~/lib/python3.7/site-packages/yaml/constructor.py", line 43, in get_single_data return self.construct_document(node) File "~/lib/python3.7/site-packages/yaml/constructor.py", line 52, in construct_document for dummy in generator: File "~/lib/python3.7/site-packages/yaml/constructor.py", line 404, in construct_yaml_map value = self.construct_mapping(node) File "~/lib/python3.7/site-packages/yaml/constructor.py", line 210, in construct_mapping return super().construct_mapping(node, deep=deep) File "~/lib/python3.7/site-packages/yaml/constructor.py", line 135, in construct_mapping value = self.construct_object(value_node, deep=deep) File "~/lib/python3.7/site-packages/yaml/constructor.py", line 94, in construct_object data = constructor(self, tag_suffix, node) File "~/lib/python3.7/site-packages/yaml/constructor.py", line 551, in construct_python_name return self.find_python_name(suffix, node.start_mark) File "~/lib/python3.7/site-packages/yaml/constructor.py", line 711, in find_python_name return super(UnsafeConstructor, self).find_python_name(name, mark, unsafe=True) File "~/lib/python3.7/site-packages/yaml/constructor.py", line 535, in find_python_name "cannot find module %r (%s)" % (module_name, exc), mark) yaml.constructor.ConstructorError: while constructing a Python object cannot find module 'detectron2._cfg_loader1c03.mask_rcnn_R_50_FPN_100ep_LSJ.py' (No module named 'detectron2._cfg_loader1c03') in "test_conf.yaml", line 99, column 18

4. please simplify the steps as much as possible so they do not require additional resources to
   run, such as a private dataset.

## Expected behavior:

Could load saved lazyconfig without error

## Environment:

Provide your environment information using the following command:

---

sys.platform linux Python 3.7.11 (default, Jul 27 2021, 14:32:16) [GCC 7.5.0] numpy 1.20.1 detectron2 0.5 @~/lib/python3.7/site-packages/detectron2 Compiler GCC 7.3 CUDA compiler CUDA 10.1 detectron2 arch flags 3.7, 5.0, 5.2, 6.0, 6.1, 7.0, 7.5 DETECTRON2_ENV_MODULE PyTorch 1.7.1+cu101 @~/lib/python3.7/site-packages/torch PyTorch debug build False GPU available Yes GPU 0 GeForce RTX 2080 (arch=7.5) CUDA_HOME /usr/local/cuda-10.1 Pillow 8.1.0 torchvision 0.8.2+cu101 @~/lib/python3.7/site-packages/torchvision torchvision arch flags 3.5, 5.0, 6.0, 7.0, 7.5 fvcore 0.1.5.post20210825 iopath 0.1.8 cv2 4.5.1

---

PyTorch built with:

• GCC 7.3
• C++ Version: 201402
• Intel(R) Math Kernel Library Version 2020.0.0 Product Build 20191122 for Intel(R) 64 architecture applications
• Intel(R) MKL-DNN v1.6.0 (Git Hash 5ef631a030a6f73131c77892041042805a06064f)
• OpenMP 201511 (a.k.a. OpenMP 4.5)
• NNPACK is enabled
• CPU capability usage: AVX2
• CUDA Runtime 10.1
• NVCC architecture flags: -gencode;arch=compute_37,code=sm_37;-gencode;arch=compute_50,code=sm_50;-gencode;arch=compute_60,code=sm_60;-gencode;arch=compute_70,code=sm_70;-gencode;arch=compute_75,code=sm_75
• CuDNN 7.6.3
• Magma 2.5.2
• Build settings: BLAS=MKL, BUILD_TYPE=Release, CXX_FLAGS= -Wno-deprecated -fvisibility-inlines-hidden -DUSE_PTHREADPOOL -fopenmp -DNDEBUG -DUSE_FBGEMM -DUSE_QNNPACK -DUSE_PYTORCH_QNNPACK -DUSE_XNNPACK -DUSE_VULKAN_WRAPPER -O2 -fPIC -Wno-narrowing -Wall -Wextra -Werror=return-type -Wno-missing-field-initializers -Wno-type-limits -Wno-array-bounds -Wno-unknown-pragmas -Wno-sign-compare -Wno-unused-parameter -Wno-unused-variable -Wno-unused-function -Wno-unused-result -Wno-unused-local-typedefs -Wno-strict-overflow -Wno-strict-aliasing -Wno-error=deprecated-declarations -Wno-stringop-overflow -Wno-psabi -Wno-error=pedantic -Wno-error=redundant-decls -Wno-error=old-style-cast -fdiagnostics-color=always -faligned-new -Wno-unused-but-set-variable -Wno-maybe-uninitialized -fno-math-errno -fno-trapping-math -Werror=format -Wno-stringop-overflow, PERF_WITH_AVX=1, PERF_WITH_AVX2=1, PERF_WITH_AVX512=1, USE_CUDA=ON, USE_EXCEPTION_PTR=1, USE_GFLAGS=OFF, USE_GLOG=OFF, USE_MKL=ON, USE_MKLDNN=ON, USE_MPI=OFF, USE_NCCL=ON, USE_NNPACK=ON, USE_OPENMP=ON,

If your issue looks like an installation issue / environment issue,
please first try to solve it yourself with the instructions in
https://detectron2.readthedocs.io/tutorials/install.html#common-installation-issues

[ppwwyyxx]

This is as expected. Because the config is a python file, there is no way to guarantee the config can be correctly saved to a yaml file since yaml has much more limited syntax.