Add feature flip for setuptools latest version

readthedocs/doc_builder/python_environments.py

@@ -117,7 +117,13 @@ def install_core_requirements(self):
         """Install basic Read the Docs requirements into the virtualenv."""
         requirements = [
             'Pygments==2.2.0',
-            'setuptools==28.8.0',
+            # Assume semver for setuptools version, support up to next backwards
+            # incompatible release
+            self.project.get_feature_value(
+                Feature.USE_SETUPTOOLS_LATEST,
+                positive='setuptools<37',
+                negative='setuptools==28.8.0',
+            ),
             'docutils==0.13.1',
             'mock==1.0.1',
             'pillow==2.6.1',
@@ -129,13 +135,14 @@ def install_core_requirements(self):
         if self.project.documentation_type == 'mkdocs':
             requirements.append('mkdocs==0.15.0')
         else:
-            if self.project.has_feature(Feature.USE_SPHINX_LATEST):
-                # We will assume semver here and only automate up to the next
-                # backward incompatible release: 2.x
-                requirements.append('sphinx<2')
-            else:
-                requirements.append('sphinx==1.5.6')
+            # We will assume semver here and only automate up to the next
+            # backward incompatible release: 2.x
             requirements.extend([
+                self.project.get_feature_value(
+                    Feature.USE_SPHINX_LATEST,
+                    positive='sphinx<2',
+                    negative='sphinx==1.5.6',
+                ),
                 'sphinx-rtd-theme<0.3',
                 'readthedocs-sphinx-ext<0.6'
             ])

readthedocs/projects/models.py

@@ -835,6 +835,14 @@ def has_feature(self, feature_id):
         """
         return self.features.filter(feature_id=feature_id).exists()
 
+    def get_feature_value(self, feature, positive, negative):
+        """Look up project feature, return corresponding value
+
+        If a project has a feature, return ``positive``, otherwise return
+        ``negative``
+        """
+        return positive if self.has_feature(feature) else negative
+
 
 class APIProject(Project):
 
@@ -994,9 +1002,11 @@ def add_features(sender, **kwargs):
     # Feature constants - this is not a exhaustive list of features, features
     # may be added by other packages
     USE_SPHINX_LATEST = 'use_sphinx_latest'
+    USE_SETUPTOOLS_LATEST = 'use_setuptools_latest'
 
     FEATURES = (
         (USE_SPHINX_LATEST, _('Use latest version of Sphinx')),
+        (USE_SETUPTOOLS_LATEST, _('Use latest version of setuptools')),
     )
 
     projects = models.ManyToManyField(