Add exceptions.GenerateIDFailed.

etiquette/exceptions.py

@@ -187,6 +187,9 @@ class FeatureDisabled(EtiquetteException):
     '''
     error_message = 'This feature has been disabled. Requires {requires}.'
 
+class GenerateIDFailed(EtiquetteException):
+    error_message = 'Could not generate unique ID on {table}. You should increase ID bits.'
+
 class MinMaxInvalid(EtiquetteException):
     '''
     For when the user searches for e.g. width=a-b but the a-b can't be parsed.

etiquette/photodb.py

@@ -1236,10 +1236,11 @@ class PhotoDB(
         table = thing_class.table
 
         length = self.config['id_bits']
-        while True:
+        for retry in range(10):
             id = RNG.getrandbits(length)
             if not self.exists(f'SELECT 1 FROM {table} WHERE id == ?', [id]):
                 return id
+        raise exceptions.GenerateIDFailed(table=table)
 
     def load_config(self) -> None:
         log.debug('Loading config file.')