id summary reporter owner description type status component version severity resolution keywords cc stage has_patch needs_docs needs_tests needs_better_patch easy ui_ux 22229 Invalid data can cause InlineFormSet.is_valid to throw ValueError anonymous Jake Rothenbuhler "The InlineFormSet's foreign key field ("""") seems to assume that its data is valid for all of the initial data. Thus, if it is altered, the database layer will fail to convert it and throw an exception, instead of reporting that the form is invalid. For an integer foreign key, this takes form of a ValueError thrown by the int function. I've created a test demonstrating the issue here: https://gist.github.com/ColonelThirtyTwo/edbc575b10b068397dc7" Bug closed Forms 1.6 Normal fixed InlineFormSet Accepted 1 0 0 0 0 0