Re_botcmd_fullmatch: Add re_botcmd_fullmatch

Closes #402

plugins/re_botcmd_fullmatch.plug

@@ -0,0 +1,10 @@
+[Core]
+name = re_botcmd_fullmatch
+module = re_botcmd_fullmatch
+
+[Documentation]
+description = Checks whether all re_botcmd regexes are fullmatches or not and warns the admins.
+
+[Python]
+version = 3
+

plugins/re_botcmd_fullmatch.py

@@ -0,0 +1,24 @@
+from errbot import BotPlugin, botcmd
+
+
+class Re_botcmd_fullmatch(BotPlugin):
+    """
+    Checks whether all re_botcmd regexes are fullmatches or not and warns the
+    admins.
+    """
+
+    @botcmd
+    def check_regexes(self, msg, args)
+        if hasattr(self.bot_config, 'RE_BOTCMD_FULLMATCH_IGNORES'):
+            ignores = self.bot_config.RE_BOTCMD_FULLMATCH_IGNORES
+        else:
+            ignores = tuple()
+
+        for name, func in dict(self._bot.re_commands).items():
+            pattern = func._err_command_re_pattern.pattern
+            if not (pattern.startswith('^') and pattern.endswith('$') and
+                    name not in ignores):
+                self.warn_admins('re_botcmd {} has a pattern `{}` that is not '
+                                 'a fullmatch. If it is intentional, please '
+                                 'add it to the `RE_BOTCMD_FULLMATCH_IGNORES` '
+                                 'config variable.'.format(name, pattern))