Fix #2436: Sphinx does not check version by :confval:needs_sphinx if loading extensions failed

CHANGES

@@ -12,6 +12,7 @@ Bugs fixed
 * #2370: the equations are slightly misaligned in LaTeX writer
 * #1817, #2077: suppress pep8 warnings on conf.py generated by sphinx-quickstart
 * #2407: building docs crash if document includes large data image URIs
+* #2436: Sphinx does not check version by :confval:`needs_sphinx` if loading extensions failed
 
 
 Release 1.4.1 (released Apr 12, 2016)

sphinx/application.py

@@ -133,6 +133,13 @@ class Sphinx(object):
         self.config.check_unicode(self.warn)
         # defer checking types until i18n has been initialized
 
+        # check the Sphinx version if requested
+        needs_sphinx = self.config.get_needs_sphinx()
+        if needs_sphinx and needs_sphinx > sphinx.__display_version__:
+            raise VersionRequirementError(
+                'This project needs at least Sphinx v%s and therefore cannot '
+                'be built with this version.' % needs_sphinx)
+
         # set confdir to srcdir if -C given (!= no confdir); a few pieces
         # of code expect a confdir to be set
         if self.confdir is None:
@@ -163,13 +170,6 @@ class Sphinx(object):
         # now that we know all config values, collect them from conf.py
         self.config.init_values(self.warn)
 
-        # check the Sphinx version if requested
-        if self.config.needs_sphinx and \
-           self.config.needs_sphinx > sphinx.__display_version__:
-            raise VersionRequirementError(
-                'This project needs at least Sphinx v%s and therefore cannot '
-                'be built with this version.' % self.config.needs_sphinx)
-
         # check extension versions if requested
         if self.config.needs_extensions:
             for extname, needs_ver in self.config.needs_extensions.items():

sphinx/config.py

@@ -338,6 +338,10 @@ class Config(object):
                      'characters; this can lead to Unicode errors occurring. '
                      'Please use Unicode strings, e.g. %r.' % (name, u'Content'))
 
+    def get_needs_sphinx(self):
+        """Obtain the value of ``needs_sphinx``"""
+        return self.overrides.get('needs_sphinx') or self._raw_config.get('needs_sphinx')
+
     def init_values(self, warn):
         config = self._raw_config
         for valname, value in iteritems(self.overrides):