[Bug] Unable to build documentation on local machine

[N00bcak]

🐛 Describe the bug

Bug

sanity-check: I did run python setup.py develop after cloning

Running make html-noplot on a fresh clone of the torchvision documentation on my local machine results in the following error:

...
reading sources... [ 69%] models/generated/torchvision.models.alexnet                                                                                                                   
====================== slowest reading durations =======================
0.332 models
0.205 generated/torchvision.transforms.v2.RandomErasing
0.179 generated/torchvision.transforms.RandomResizedCrop
0.157 datasets
0.139 generated/torchvision.ops.DropBlock3d

Exception occurred:
  File "/home/n00bcak/Desktop/programming/venvs/torchvision-dev/lib/python3.11/site-packages/sphinx/ext/autodoc/__init__.py", line 347, in add_line
    if line.strip():  # not a blank line
       ^^^^^^^^^^
AttributeError: 'NoneType' object has no attribute 'strip'

Expected Result

Sphinx continues building as usual.

(Guessed) Source of Problem

I am not familiar with Sphinx, perhaps it is something to do with the configs?

Versions

2024-08-09 22:14:52 (16.3 MB/s) - ‘collect_env.py.1’ saved [23357/23357]

Collecting environment information...
PyTorch version: 2.4.0+cu121
Is debug build: False
CUDA used to build PyTorch: 12.1
ROCM used to build PyTorch: N/A

OS: Ubuntu 24.04 LTS (x86_64)
GCC version: (Ubuntu 13.2.0-23ubuntu4) 13.2.0
Clang version: Could not collect
CMake version: version 3.28.3
Libc version: glibc-2.39

Python version: 3.11.9 (main, Jul 25 2024, 10:33:02) [GCC 13.2.0] (64-bit runtime)
Python platform: Linux-6.8.0-39-generic-x86_64-with-glibc2.39
Is CUDA available: True
CUDA runtime version: 12.0.140
CUDA_MODULE_LOADING set to: LAZY
GPU models and configuration: GPU 0: NVIDIA GeForce RTX 3090
Nvidia driver version: 535.183.01
cuDNN version: Could not collect
HIP runtime version: N/A
MIOpen runtime version: N/A
Is XNNPACK available: True

CPU:
Architecture:                         x86_64
CPU op-mode(s):                       32-bit, 64-bit
Address sizes:                        39 bits physical, 48 bits virtual
Byte Order:                           Little Endian
CPU(s):                               24
On-line CPU(s) list:                  0-23
Vendor ID:                            GenuineIntel
Model name:                           13th Gen Intel(R) Core(TM) i7-13700KF
CPU family:                           6
Model:                                183
Thread(s) per core:                   2
Core(s) per socket:                   16
Socket(s):                            1
Stepping:                             1
CPU(s) scaling MHz:                   70%
CPU max MHz:                          5500.0000
CPU min MHz:                          800.0000
BogoMIPS:                             6835.20
Flags:                                fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc art arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc cpuid aperfmperf tsc_known_freq pni pclmulqdq dtes64 monitor ds_cpl vmx est tm2 ssse3 sdbg fma cx16 xtpr pdcm sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch cpuid_fault ssbd ibrs ibpb stibp ibrs_enhanced tpr_shadow flexpriority ept vpid ept_ad fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms invpcid rdseed adx smap clflushopt clwb intel_pt sha_ni xsaveopt xsavec xgetbv1 xsaves split_lock_detect user_shstk avx_vnni dtherm ida arat pln pts hwp hwp_notify hwp_act_window hwp_epp hwp_pkg_req hfi vnmi umip pku ospke waitpkg gfni vaes vpclmulqdq rdpid movdiri movdir64b fsrm md_clear serialize arch_lbr ibt flush_l1d arch_capabilities
Virtualization:                       VT-x
L1d cache:                            640 KiB (16 instances)
L1i cache:                            768 KiB (16 instances)
L2 cache:                             24 MiB (10 instances)
L3 cache:                             30 MiB (1 instance)
NUMA node(s):                         1
NUMA node0 CPU(s):                    0-23
Vulnerability Gather data sampling:   Not affected
Vulnerability Itlb multihit:          Not affected
Vulnerability L1tf:                   Not affected
Vulnerability Mds:                    Not affected
Vulnerability Meltdown:               Not affected
Vulnerability Mmio stale data:        Not affected
Vulnerability Reg file data sampling: Mitigation; Clear Register File
Vulnerability Retbleed:               Not affected
Vulnerability Spec rstack overflow:   Not affected
Vulnerability Spec store bypass:      Mitigation; Speculative Store Bypass disabled via prctl
Vulnerability Spectre v1:             Mitigation; usercopy/swapgs barriers and __user pointer sanitization
Vulnerability Spectre v2:             Mitigation; Enhanced / Automatic IBRS; IBPB conditional; RSB filling; PBRSB-eIBRS SW sequence; BHI BHI_DIS_S
Vulnerability Srbds:                  Not affected
Vulnerability Tsx async abort:        Not affected

Versions of relevant libraries:
[pip3] numpy==2.0.1
[pip3] numpy==2.0.1
[pip3] pytorch_sphinx_theme==0.0.24
[pip3] torch==2.4.0
[pip3] torchvision==0.20.0a0+0d80848
[pip3] triton==3.0.0
[conda] Could not collect

FWIW, error also observed on MacOS Sonoma.

[sclarkson]

The problem is here.

vision/docs/source/conf.py

Lines 386 to 389 in 0d80848

	if obj.__doc__ != "An enumeration.":
	# We only show the custom enum doc if it was overridden. The default one from Python is "An enumeration"
	lines.append("")
	lines.append(obj.__doc__)

In Python 3.11+, the model weight enums don't get that default docstring that the build is expecting.

Changing it to if obj.__doc__ is not None and obj.__doc__ != "An enumeration.": solves the problem.

[NicolasHug]

Thanks a lot @N00bcak for the report and @sclarkson for the suggested fix. I just merged #8583 which should fix the issue.