Fix #2407: building docs crash if document includes large data image URIs

CHANGES

@@ -11,6 +11,7 @@ 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
 
 
 Release 1.4.1 (released Apr 12, 2016)

sphinx/environment.py

@@ -907,7 +907,11 @@ class BuildEnvironment:
             # The special key ? is set for nonlocal URIs.
             node['candidates'] = candidates = {}
             imguri = node['uri']
-            if imguri.find('://') != -1:
+            if imguri.startswith('data:'):
+                self.warn_node('image data URI found. some builders might not support', node)
+                candidates['?'] = imguri
+                continue
+            elif imguri.find('://') != -1:
                 self.warn_node('nonlocal image URI found: %s' % imguri, node)
                 candidates['?'] = imguri
                 continue