Fixed #22823 (and partly #22563) - FKs from unmigrated apps breaking state.

Thanks to bendavis78 for the test and diagnostic work.

django/db/migrations/state.py

@@ -44,11 +44,13 @@ class ProjectState(object):
             # Any apps in self.real_apps should have all their models included
             # in the render. We don't use the original model instances as there
             # are some variables that refer to the Apps object.
+            # FKs/M2Ms from real apps are also not included as they just
+            # mess things up with partial states (due to lack of dependencies)
             real_models = []
             for app_label in self.real_apps:
                 app = global_apps.get_app_config(app_label)
                 for model in app.get_models():
-                    real_models.append(ModelState.from_model(model))
+                    real_models.append(ModelState.from_model(model, exclude_rels=True))
             # Populate the app registry with a stub for each application.
             app_labels = set(model_state.app_label for model_state in self.models.values())
             self.apps = Apps([AppConfigStub(label) for label in sorted(self.real_apps + list(app_labels))])
@@ -155,13 +157,15 @@ class ModelState(object):
                 )
 
     @classmethod
-    def from_model(cls, model):
+    def from_model(cls, model, exclude_rels=False):
         """
         Feed me a model, get a ModelState representing it out.
         """
         # Deconstruct the fields
         fields = []
         for field in model._meta.local_fields:
+            if getattr(field, "rel", None) and exclude_rels:
+                continue
             name, path, args, kwargs = field.deconstruct()
             field_class = import_string(path)
             try:
@@ -173,17 +177,18 @@ class ModelState(object):
                     model._meta.object_name,
                     e,
                 ))
-        for field in model._meta.local_many_to_many:
-            name, path, args, kwargs = field.deconstruct()
-            field_class = import_string(path)
-            try:
-                fields.append((name, field_class(*args, **kwargs)))
-            except TypeError as e:
-                raise TypeError("Couldn't reconstruct m2m field %s on %s: %s" % (
-                    name,
-                    model._meta.object_name,
-                    e,
-                ))
+        if not exclude_rels:
+            for field in model._meta.local_many_to_many:
+                name, path, args, kwargs = field.deconstruct()
+                field_class = import_string(path)
+                try:
+                    fields.append((name, field_class(*args, **kwargs)))
+                except TypeError as e:
+                    raise TypeError("Couldn't reconstruct m2m field %s on %s: %s" % (
+                        name,
+                        model._meta.object_name,
+                        e,
+                    ))
         # Extract the options
         options = {}
         for name in DEFAULT_NAMES:

tests/migrations/migrations_test_apps/migrated_app/migrations/0001_initial.py

+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    operations = [
+
+        migrations.CreateModel(
+            "Author",
+            [
+                ("id", models.AutoField(primary_key=True)),
+                ("name", models.CharField(max_length=255)),
+                ("slug", models.SlugField(null=True)),
+                ("age", models.IntegerField(default=0)),
+                ("silly_field", models.BooleanField(default=False)),
+            ],
+        ),
+
+        migrations.CreateModel(
+            "Tribble",
+            [
+                ("id", models.AutoField(primary_key=True)),
+                ("fluffy", models.BooleanField(default=True)),
+            ],
+        )
+
+    ]

tests/migrations/migrations_test_apps/migrated_unapplied_app/migrations/0001_initial.py

+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    operations = [
+
+        migrations.CreateModel(
+            "OtherAuthor",
+            [
+                ("id", models.AutoField(primary_key=True)),
+                ("name", models.CharField(max_length=255)),
+                ("slug", models.SlugField(null=True)),
+                ("age", models.IntegerField(default=0)),
+                ("silly_field", models.BooleanField(default=False)),
+            ],
+        ),
+
+    ]

tests/migrations/migrations_test_apps/migrated_unapplied_app/models.py

+from django.db import models
+
+
+class OtherAuthor(models.Model):
+    id = models.AutoField(primary_key=True)
+    name = models.CharField(max_length=255)
+    slug = models.SlugField(null=True)
+    age = models.IntegerField(default=0)
+    silly_field = models.BooleanField(default=False)
+
+    class Meta:
+        app_label = "migrated_unapplied_app"

tests/migrations/migrations_test_apps/unmigrated_app/models.py

+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+from django.db import models
+
+
+class SillyModel(models.Model):
+    silly_field = models.BooleanField(default=False)
+    silly_tribble = models.ForeignKey("migrations.Tribble")
+    is_trouble = models.BooleanField(default=True)

tests/migrations/test_commands.py

@@ -102,6 +102,29 @@ class MigrateTests(MigrationTestBase):
         call_command("sqlmigrate", "migrations", "0001", stdout=stdout, backwards=True)
         self.assertIn("drop table", stdout.getvalue().lower())
 
+    @override_system_checks([])
+    @override_settings(
+        INSTALLED_APPS=[
+            "migrations.migrations_test_apps.migrated_app",
+            "migrations.migrations_test_apps.migrated_unapplied_app",
+            "migrations.migrations_test_apps.unmigrated_app"])
+    def test_regression_22823_unmigrated_fk_to_migrated_model(self):
+        """
+        https://code.djangoproject.com/ticket/22823
+
+        Assuming you have 3 apps, `A`, `B`, and `C`, such that:
+
+        * `A` has migrations
+        * `B` has a migration we want to apply
+        * `C` has no migrations, but has an FK to `A`
+
+        When we try to migrate "B", an exception occurs because the
+        "B" was not included in the ProjectState that is used to detect
+        soft-applied migrations.
+        """
+        stdout = six.StringIO()
+        call_command("migrate", "migrated_unapplied_app", stdout=stdout)
+
 
 class MakeMigrationsTests(MigrationTestBase):
     """