Fixed #25850 -- Made migrate/makemigrations error on inconsistent history.

django/core/management/commands/makemigrations.py

@@ -5,6 +5,7 @@ from itertools import takewhile
 
 from django.apps import apps
 from django.core.management.base import BaseCommand, CommandError
+from django.db import connections
 from django.db.migrations import Migration
 from django.db.migrations.autodetector import MigrationAutodetector
 from django.db.migrations.loader import MigrationLoader
@@ -75,6 +76,10 @@ class Command(BaseCommand):
         # the loader doesn't try to resolve replaced migrations from DB.
         loader = MigrationLoader(None, ignore_no_migrations=True)
 
+        # Raise an error if any migrations are applied before their dependencies.
+        for db in connections:
+            loader.check_consistent_history(connections[db])
+
         # Before anything else, see if there's conflicting apps and drop out
         # hard if there are any and they don't want to merge
         conflicts = loader.detect_conflicts()

django/core/management/commands/migrate.py

@@ -65,6 +65,9 @@ class Command(BaseCommand):
         # Work out which apps have migrations and which do not
         executor = MigrationExecutor(connection, self.migration_progress_callback)
 
+        # Raise an error if any migrations are applied before their dependencies.
+        executor.loader.check_consistent_history(connection)
+
         # Before anything else, see if there's conflicting apps and drop out
         # hard if there are any
         conflicts = executor.loader.detect_conflicts()

django/db/migrations/exceptions.py

@@ -25,6 +25,13 @@ class CircularDependencyError(Exception):
     pass
 
 
+class InconsistentMigrationHistory(Exception):
+    """
+    Raised when an applied migration has some of its dependencies not applied.
+    """
+    pass
+
+
 class InvalidBasesError(ValueError):
     """
     Raised when a model's base classes can't be resolved.

django/db/migrations/loader.py

@@ -10,7 +10,10 @@ from django.db.migrations.graph import MigrationGraph
 from django.db.migrations.recorder import MigrationRecorder
 from django.utils import six
 
-from .exceptions import AmbiguityError, BadMigrationError, NodeNotFoundError
+from .exceptions import (
+    AmbiguityError, BadMigrationError, InconsistentMigrationHistory,
+    NodeNotFoundError,
+)
 
 MIGRATIONS_MODULE_NAME = 'migrations'
 
@@ -318,6 +321,25 @@ class MigrationLoader(object):
                         # "child" is not in there.
                         _reraise_missing_dependency(migration, child, e)
 
+    def check_consistent_history(self, connection):
+        """
+        Raise InconsistentMigrationHistory if any applied migrations have
+        unapplied dependencies.
+        """
+        recorder = MigrationRecorder(connection)
+        applied = recorder.applied_migrations()
+        for migration in applied:
+            # If the migration is unknown, skip it.
+            if migration not in self.graph.nodes:
+                continue
+            for parent in self.graph.node_map[migration].parents:
+                if parent not in applied:
+                    raise InconsistentMigrationHistory(
+                        "Migration {}.{} is applied before its dependency {}.{}".format(
+                            migration[0], migration[1], parent[0], parent[1],
+                        )
+                    )
+
     def detect_conflicts(self):
         """
         Looks through the loaded graph and detects any conflicts - apps