fix build docs

docs/requirements.txt

--f https://download.pytorch.org/whl/nightly/cpu/torch_nightly.html
-numpy
-torch_nightly
 sphinx
 sphinx_rtd_theme
 sphinx-autodoc-typehints

torch_scatter/__init__.py

@@ -19,7 +19,10 @@ except OSError as e:
             raise RuntimeError(
                 f'Expected PyTorch version {t_major}.{t_minor} but found '
                 f'version {major}.{minor}.')
-    raise OSError(e)
+    if os.getenv('BUILD_DOCS', '0') == '1':
+        pass
+    else:
+        raise OSError(e)
 
 from .scatter import (scatter_sum, scatter_add, scatter_mean, scatter_min,
                       scatter_max, scatter)

torch_scatter/scatter.py

+import os
 import importlib
 import os.path as osp
 from typing import Optional, Tuple
@@ -6,8 +7,14 @@ import torch
 
 from .utils import broadcast
 
-torch.ops.load_library(importlib.machinery.PathFinder().find_spec(
-    '_scatter', [osp.dirname(__file__)]).origin)
+try:
+    torch.ops.load_library(importlib.machinery.PathFinder().find_spec(
+        '_scatter', [osp.dirname(__file__)]).origin)
+except OSError as e:
+    if os.getenv('BUILD_DOCS', '0') == '1':
+        pass
+    else:
+        raise OSError(e)
 
 
 @torch.jit.script

torch_scatter/segment_coo.py

+import os
 import importlib
 import os.path as osp
 from typing import Optional, Tuple
 
 import torch
 
-torch.ops.load_library(importlib.machinery.PathFinder().find_spec(
-    '_segment_coo', [osp.dirname(__file__)]).origin)
+try:
+    torch.ops.load_library(importlib.machinery.PathFinder().find_spec(
+        '_segment_coo', [osp.dirname(__file__)]).origin)
+except OSError as e:
+    if os.getenv('BUILD_DOCS', '0') == '1':
+        pass
+    else:
+        raise OSError(e)
 
 
 @torch.jit.script

torch_scatter/segment_csr.py

+import os
 import importlib
 import os.path as osp
 from typing import Optional, Tuple
 
 import torch
 
-torch.ops.load_library(importlib.machinery.PathFinder().find_spec(
-    '_segment_csr', [osp.dirname(__file__)]).origin)
+try:
+    torch.ops.load_library(importlib.machinery.PathFinder().find_spec(
+        '_segment_csr', [osp.dirname(__file__)]).origin)
+except OSError as e:
+    if os.getenv('BUILD_DOCS', '0') == '1':
+        pass
+    else:
+        raise OSError(e)
 
 
 @torch.jit.script