i3bar has some issues with locale-handling I guess.

It reliably crashes i3pystatus, but only if started by i3bar. Meh.
I can't tell if this locale issue is local (ha-ha) or everyone is affected.

i3pystatus/__init__.py

@@ -109,6 +109,10 @@ class Module(SettingsBase):
     def registered(self, status_handler):
         """Called when this module is registered with a status handler"""
 
+    def inject(self, json):
+        if self.output:
+            json.insert(self.position, self.output)
+
 class AsyncModule(Module):
     def registered(self, status_handler):
         self.thread = Thread(target=self.mainloop)
@@ -298,5 +302,5 @@ class i3pystatus:
     def run(self):
         for j in JSONIO(self.io).read():
             for module in self.modules:
-                j.insert(module.position, module.output)
+                module.inject(j)
 I3statusHandler = i3pystatus

i3pystatus/clock.py

@@ -14,10 +14,21 @@ class Clock(IntervalModule):
     format = None
 
     def init(self):
+        if self.format is None:
+            #
+            # WARNING
+            # i3bar does something with the locale, wich probably
+            # crashes i3pystatus when the code block below is run.
+            # I don't know how to debug i3bar (I doubt it has any
+            # debugging facilities).
+            #
+            # If your i3bar stays blank after enabling clock, well,
+            # just set the format string and it should work :-)
+            #
+
             lang = os.environ.get('LANG', None)
             if lang:
                 locale.setlocale(locale.LC_ALL, lang)
-        if self.format is None:
             lang = locale.getlocale()[0]
             if lang == 'en_US':
                 # MDY format - United States of America