[Enhance] Update digit_version function. (open-mmlab#402)

* Update digit_version

* Add digit_version unit test

mmcls/__init__.py

@@ -1,18 +1,49 @@
+import warnings
+
 import mmcv
+from packaging.version import parse
 
 from .version import __version__
 
 
-def digit_version(version_str):
-    digit_version = []
-    for x in version_str.split('.'):
-        if x.isdigit():
-            digit_version.append(int(x))
-        elif x.find('rc') != -1:
-            patch_version = x.split('rc')
-            digit_version.append(int(patch_version[0]) - 1)
-            digit_version.append(int(patch_version[1]))
-    return digit_version
+def digit_version(version_str: str, length: int = 4):
+    """Convert a version string into a tuple of integers.
+
+    This method is usually used for comparing two versions. For pre-release
+    versions: alpha < beta < rc.
+
+    Args:
+        version_str (str): The version string.
+        length (int): The maximum number of version levels. Default: 4.
+
+    Returns:
+        tuple[int]: The version info in digits (integers).
+    """
+    version = parse(version_str)
+    assert version.release, f'failed to parse version {version_str}'
+    release = list(version.release)
+    release = release[:length]
+    if len(release) < length:
+        release = release + [0] * (length - len(release))
+    if version.is_prerelease:
+        mapping = {'a': -3, 'b': -2, 'rc': -1}
+        val = -4
+        # version.pre can be None
+        if version.pre:
+            if version.pre[0] not in mapping:
+                warnings.warn(f'unknown prerelease version {version.pre[0]}, '
+                              'version checking may go wrong')
+            else:
+                val = mapping[version.pre[0]]
+            release.extend([val, version.pre[-1]])
+        else:
+            release.extend([val, 0])
+
+    elif version.is_postrelease:
+        release.extend([1, version.post])
+    else:
+        release.extend([0, 0])
+    return tuple(release)
 
 
 mmcv_minimum_version = '1.3.8'
@@ -25,4 +56,4 @@ def digit_version(version_str):
     f'MMCV=={mmcv.__version__} is used but incompatible. ' \
     f'Please install mmcv>={mmcv_minimum_version}, <={mmcv_maximum_version}.'
 
-__all__ = ['__version__']
+__all__ = ['__version__', 'digit_version']

setup.cfg

@@ -14,6 +14,6 @@ line_length = 79
 multi_line_output = 0
 known_standard_library = pkg_resources,setuptools
 known_first_party = mmcls
-known_third_party = PIL,cv2,matplotlib,mmcv,mmdet,numpy,onnxruntime,pytest,seaborn,torch,torchvision,ts
+known_third_party = PIL,cv2,matplotlib,mmcv,mmdet,numpy,onnxruntime,packaging,pytest,seaborn,torch,torchvision,ts
 no_lines_before = STDLIB,LOCALFOLDER
 default_section = THIRDPARTY

tests/test_utils/test_version_utils.py

@@ -0,0 +1,20 @@
+from mmcls import digit_version
+
+
+def test_digit_version():
+    assert digit_version('0.2.16') == (0, 2, 16, 0, 0, 0)
+    assert digit_version('1.2.3') == (1, 2, 3, 0, 0, 0)
+    assert digit_version('1.2.3rc0') == (1, 2, 3, 0, -1, 0)
+    assert digit_version('1.2.3rc1') == (1, 2, 3, 0, -1, 1)
+    assert digit_version('1.0rc0') == (1, 0, 0, 0, -1, 0)
+    assert digit_version('1.0') == digit_version('1.0.0')
+    assert digit_version('1.5.0+cuda90_cudnn7.6.3_lms') == digit_version('1.5')
+    assert digit_version('1.0.0dev') < digit_version('1.0.0a')
+    assert digit_version('1.0.0a') < digit_version('1.0.0a1')
+    assert digit_version('1.0.0a') < digit_version('1.0.0b')
+    assert digit_version('1.0.0b') < digit_version('1.0.0rc')
+    assert digit_version('1.0.0rc1') < digit_version('1.0.0')
+    assert digit_version('1.0.0') < digit_version('1.0.0post')
+    assert digit_version('1.0.0post') < digit_version('1.0.0post1')
+    assert digit_version('v1') == (1, 0, 0, 0, 0, 0)
+    assert digit_version('v1.1.5') == (1, 1, 5, 0, 0, 0)