diff --git a/django/core/management.py b/django/core/management.py index 06c31abe13c..e474072e838 100644 --- a/django/core/management.py +++ b/django/core/management.py @@ -646,6 +646,13 @@ def get_validation_errors(outfile): if not type(c) in (tuple, list) or len(c) != 2: e.add(opts, '"%s" field: "choices" should be a sequence of two-tuples.' % f.name) + # Check for multiple ManyToManyFields to the same object, and + # verify "singular" is set in that case. + for i, f in enumerate(opts.many_to_many): + for previous_f in opts.many_to_many[:i]: + if f.rel.to == previous_f.rel.to and f.rel.singular == previous_f.rel.singular: + e.add(opts, 'The "%s" field requires a "singular" parameter, because the %s model has more than one ManyToManyField to the same model (%s).' % (f.name, opts.object_name, previous_f.rel.to.object_name)) + # Check admin attribute. if opts.admin is not None: if not isinstance(opts.admin, meta.Admin):