          ("book", models.ForeignKey("otherapp.Book")),
      ])
      edition = ModelState("thirdapp", "Edition", [
          ("id", models.AutoField(primary_key=True)),
          ("book", models.ForeignKey("otherapp.Book")),
      ])
      custom_user = ModelState("thirdapp", "CustomUser", [
          ("id", models.AutoField(primary_key=True)),
          ("username", models.CharField(max_length=255)),
      ], bases=(AbstractBaseUser, ))
 
</s> remove         ("author", models.ForeignKey("testapp.Author")),
        ("book", models.ForeignKey("otherapp.Book")),
 </s> add         ("author", models.ForeignKey("testapp.Author", models.CASCADE)),
        ("book", models.ForeignKey("otherapp.Book", models.CASCADE)), </s> remove         ("book", models.ForeignKey("otherapp.Book")),
 </s> add         ("book", models.ForeignKey("otherapp.Book", models.CASCADE)), </s> remove         ("book", models.ForeignKey("otherapp.Book")),
 </s> add         ("book", models.ForeignKey("otherapp.Book", models.CASCADE)), </s> remove         ("book", models.ForeignKey("otherapp.Book")),
 </s> add         ("book", models.ForeignKey("otherapp.Book", models.CASCADE)), </s> remove         ("author", models.ForeignKey("otherapp.Book")),
 </s> add         ("author", models.ForeignKey("otherapp.Book", models.CASCADE)),
        ("book", models.ForeignKey("otherapp.Book", models.CASCADE)),
          ("book", models.ForeignKey("otherapp.Book")),
      ])
      edition = ModelState("thirdapp", "Edition", [
          ("id", models.AutoField(primary_key=True)),
        ("book", models.ForeignKey("otherapp.Book", models.CASCADE)),
      ])
      custom_user = ModelState("thirdapp", "CustomUser", [
          ("id", models.AutoField(primary_key=True)),
          ("username", models.CharField(max_length=255)),
      ], bases=(AbstractBaseUser, ))
keep keep keep keep replace keep keep keep keep keep
 Fixed #21127 -- Started deprecation toward requiring on_delete for ForeignKey/OneToOneField 
tests/migrations/test_autodetector.py