Make handling of setuptools-scm in setup more robust

Fixes #181

setup.py

@@ -19,64 +19,66 @@ requirements_setup = read_req('setup.txt')
 requirements_validation = read_req('validation.txt')
 
 
-try:
-    # this is a workaround for being able to install the package from source without working from a git checkout
-    # it is needed for building succesfully on Heroku
-    from setuptools_scm import get_version
-except ImportError:
-    get_version = None
+def drf_yasg_setup(**kwargs):
+    setup(
+        name='drf-yasg',
+        packages=find_packages('src'),
+        package_dir={'': 'src'},
+        include_package_data=True,
+        install_requires=requirements,
+        setup_requires=requirements_setup,
+        extras_require={
+            'validation': requirements_validation,
+        },
+        license='BSD License',
+        description='Automated generation of real Swagger/OpenAPI 2.0 schemas from Django Rest Framework code.',
+        long_description=description,
+        url='https://github.com/axnsan12/drf-yasg',
+        author='Cristi V.',
+        author_email='cristi@cvjd.me',
+        keywords='drf django django-rest-framework schema swagger openapi codegen swagger-codegen '
+                 'documentation drf-yasg django-rest-swagger drf-openapi',
+        python_requires=">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*",
+        classifiers=[
+            'Intended Audience :: Developers',
+            'License :: OSI Approved :: BSD License',
+            'Development Status :: 5 - Production/Stable',
+            'Operating System :: OS Independent',
+            'Environment :: Web Environment',
+            'Programming Language :: Python',
+            'Programming Language :: Python :: 2',
+            'Programming Language :: Python :: 2.7',
+            'Programming Language :: Python :: 3',
+            'Programming Language :: Python :: 3.4',
+            'Programming Language :: Python :: 3.5',
+            'Programming Language :: Python :: 3.6',
+            'Programming Language :: Python :: 3.7',
+            'Framework :: Django',
+            'Framework :: Django :: 1.11',
+            'Framework :: Django :: 2.0',
+            'Framework :: Django :: 2.1',
+            'Topic :: Documentation',
+            'Topic :: Software Development :: Code Generators',
+        ],
+        **kwargs
+    )
+
 
 try:
-    version = get_version()
-    version_kwargs = {'use_scm_version': True}
-except Exception:
-    if any(any(dist in arg for dist in ['sdist', 'bdist']) for arg in sys.argv):
+    drf_yasg_setup(use_scm_version=True)
+except LookupError as e:
+    if os.getenv('CI', 'false') == 'true' or os.getenv('TRAVIS', 'false') == 'true':
         raise
 
-    import time
-    timestamp_ms = int(time.time() * 1000)
-    timestamp_str = hex(timestamp_ms)[2:].zfill(16)
-    version_kwargs = {'version': '0.0.0rc0+dummy.' + timestamp_str}
+    if 'setuptools-scm' in str(e):
+        import time
 
-setup(
-    name='drf-yasg',
-    packages=find_packages('src'),
-    package_dir={'': 'src'},
-    include_package_data=True,
-    install_requires=requirements,
-    setup_requires=requirements_setup,
-    extras_require={
-        'validation': requirements_validation,
-    },
-    license='BSD License',
-    description='Automated generation of real Swagger/OpenAPI 2.0 schemas from Django Rest Framework code.',
-    long_description=description,
-    url='https://github.com/axnsan12/drf-yasg',
-    author='Cristi V.',
-    author_email='cristi@cvjd.me',
-    keywords='drf django django-rest-framework schema swagger openapi codegen swagger-codegen '
-             'documentation drf-yasg django-rest-swagger drf-openapi',
-    python_requires=">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*",
-    classifiers=[
-        'Intended Audience :: Developers',
-        'License :: OSI Approved :: BSD License',
-        'Development Status :: 5 - Production/Stable',
-        'Operating System :: OS Independent',
-        'Environment :: Web Environment',
-        'Programming Language :: Python',
-        'Programming Language :: Python :: 2',
-        'Programming Language :: Python :: 2.7',
-        'Programming Language :: Python :: 3',
-        'Programming Language :: Python :: 3.4',
-        'Programming Language :: Python :: 3.5',
-        'Programming Language :: Python :: 3.6',
-        'Programming Language :: Python :: 3.7',
-        'Framework :: Django',
-        'Framework :: Django :: 1.11',
-        'Framework :: Django :: 2.0',
-        'Framework :: Django :: 2.1',
-        'Topic :: Documentation',
-        'Topic :: Software Development :: Code Generators',
-    ],
-    **version_kwargs
-)
+        timestamp_ms = int(time.time() * 1000)
+        timestamp_str = hex(timestamp_ms)[2:].zfill(16)
+        dummy_version = '0.0.0rc0+noscm' + timestamp_str
+
+        drf_yasg_setup(version=dummy_version)
+        print(str(e), file=sys.stderr)
+        print("failed to detect version, build was done using dummy version " + dummy_version, file=sys.stderr)
+    else:
+        raise