First stab at some migration creation commands

10 files changed, 203 insertions, 45 deletions

diff --git a/django/core/management/commands/makemigration.py b/django/core/management/commands/makemigration.py
new file mode 100644
index 0000000000..fd12652036
--- /dev/null
+++ b/django/core/management/commands/makemigration.py
@@ -0,0 +1,52 @@
+import sys
+from optparse import make_option
+
+from django.core.management.base import BaseCommand
+from django.core.management.color import color_style
+from django.core.exceptions import ImproperlyConfigured
+from django.db import connections
+from django.db.migrations.loader import MigrationLoader
+from django.db.migrations.autodetector import MigrationAutodetector, InteractiveMigrationQuestioner
+from django.db.migrations.state import ProjectState
+from django.db.models.loading import cache
+
+
+class Command(BaseCommand):
+    option_list = BaseCommand.option_list + (
+        make_option('--empty', action='store_true', dest='empty', default=False,
+            help='Make a blank migration.'),
+    )
+
+    help = "Creates new migration(s) for apps."
+    usage_str = "Usage: ./manage.py createmigration [--empty] [app [app ...]]"
+
+    def handle(self, *app_labels, **options):
+
+        self.verbosity = int(options.get('verbosity'))
+        self.interactive = options.get('interactive')
+        self.style = color_style()
+
+        # Make sure the app they asked for exists
+        app_labels = set(app_labels)
+        for app_label in app_labels:
+            try:
+                cache.get_app(app_label)
+            except ImproperlyConfigured:
+                self.stderr.write("The app you specified - '%s' - could not be found. Is it in INSTALLED_APPS?" % app_label)
+                sys.exit(2)
+
+        # Load the current graph state
+        loader = MigrationLoader(connections["default"])
+
+        # Detect changes
+        autodetector = MigrationAutodetector(
+            loader.graph.project_state(),
+            ProjectState.from_app_cache(cache),
+            InteractiveMigrationQuestioner(specified_apps=app_labels),
+        )
+        changes = autodetector.changes()
+        changes = autodetector.arrange_for_graph(changes, loader.graph)
+        if app_labels:
+            changes = autodetector.trim_to_apps(changes, app_labels)
+
+        print changes
diff --git a/django/core/management/commands/migrate.py b/django/core/management/commands/migrate.py
index 68897fe19c..0f12508559 100644
--- a/django/core/management/commands/migrate.py
+++ b/django/core/management/commands/migrate.py
@@ -5,7 +5,7 @@ import traceback
 from django.conf import settings
 from django.core.management import call_command
 from django.core.management.base import NoArgsCommand
-from django.core.management.color import color_style
+from django.core.management.color import color_style, no_style
 from django.core.management.sql import custom_sql_for_model, emit_post_sync_signal, emit_pre_sync_signal
 from django.db import connections, router, transaction, models, DEFAULT_DB_ALIAS
 from django.db.migrations.executor import MigrationExecutor
@@ -32,6 +32,7 @@ class Command(NoArgsCommand):
         self.interactive = options.get('interactive')
         self.show_traceback = options.get('traceback')
         self.load_initial_data = options.get('load_initial_data')
+        self.test_database = options.get('test_database', False)
 
         self.style = color_style()
 
@@ -144,14 +145,14 @@ class Command(NoArgsCommand):
                     # Create the model's database table, if it doesn't already exist.
                     if self.verbosity >= 3:
                         self.stdout.write("    Processing %s.%s model\n" % (app_name, model._meta.object_name))
-                    sql, references = connection.creation.sql_create_model(model, self.style, seen_models)
+                    sql, references = connection.creation.sql_create_model(model, no_style(), seen_models)
                     seen_models.add(model)
                     created_models.add(model)
                     for refto, refs in references.items():
                         pending_references.setdefault(refto, []).extend(refs)
                         if refto in seen_models:
-                            sql.extend(connection.creation.sql_for_pending_references(refto, self.style, pending_references))
-                    sql.extend(connection.creation.sql_for_pending_references(model, self.style, pending_references))
+                            sql.extend(connection.creation.sql_for_pending_references(refto, no_style(), pending_references))
+                    sql.extend(connection.creation.sql_for_pending_references(model, no_style(), pending_references))
                     if self.verbosity >= 1 and sql:
                         self.stdout.write("    Creating table %s\n" % model._meta.db_table)
                     for statement in sql:
@@ -172,7 +173,7 @@ class Command(NoArgsCommand):
         for app_name, model_list in manifest.items():
             for model in model_list:
                 if model in created_models:
-                    custom_sql = custom_sql_for_model(model, self.style, connection)
+                    custom_sql = custom_sql_for_model(model, no_style(), connection)
                     if custom_sql:
                         if self.verbosity >= 2:
                             self.stdout.write("    Installing custom SQL for %s.%s model\n" % (app_name, model._meta.object_name))
@@ -194,7 +195,7 @@ class Command(NoArgsCommand):
         for app_name, model_list in manifest.items():
             for model in model_list:
                 if model in created_models:
-                    index_sql = connection.creation.sql_indexes_for_model(model, self.style)
+                    index_sql = connection.creation.sql_indexes_for_model(model, no_style())
                     if index_sql:
                         if self.verbosity >= 2:
                             self.stdout.write("    Installing index for %s.%s model\n" % (app_name, model._meta.object_name))
diff --git a/django/db/migrations/autodetector.py b/django/db/migrations/autodetector.py
index be3e1c561f..f89634f57b 100644
--- a/django/db/migrations/autodetector.py
+++ b/django/db/migrations/autodetector.py
@@ -1,6 +1,8 @@
 import re
+from django.utils.six.moves import input
 from django.db.migrations import operations
 from django.db.migrations.migration import Migration
+from django.db.models.loading import cache
 
 
 class MigrationAutodetector(object):
@@ -16,9 +18,10 @@ class MigrationAutodetector(object):
     if it wishes, with the caveat that it may not always be possible.
     """
 
-    def __init__(self, from_state, to_state):
+    def __init__(self, from_state, to_state, questioner=None):
         self.from_state = from_state
         self.to_state = to_state
+        self.questioner = questioner or MigrationQuestioner()
 
     def changes(self):
         """
@@ -54,7 +57,7 @@ class MigrationAutodetector(object):
                     model_state.name,
                 )
             )
-        # Alright, now sort out and return the migrations
+        # Alright, now add internal dependencies
         for app_label, migrations in self.migrations.items():
             for m1, m2 in zip(migrations, migrations[1:]):
                 m2.dependencies.append((app_label, m1.name))
@@ -68,34 +71,7 @@ class MigrationAutodetector(object):
             migrations.append(instance)
         migrations[-1].operations.append(operation)
 
-    @classmethod
-    def suggest_name(cls, ops):
-        """
-        Given a set of operations, suggests a name for the migration
-        they might represent. Names not guaranteed to be unique; they
-        must be prefixed by a number or date.
-        """
-        if len(ops) == 1:
-            if isinstance(ops[0], operations.CreateModel):
-                return ops[0].name.lower()
-            elif isinstance(ops[0], operations.DeleteModel):
-                return "delete_%s" % ops[0].name.lower()
-        elif all(isinstance(o, operations.CreateModel) for o in ops):
-            return "_".join(sorted(o.name.lower() for o in ops))
-        return "auto"
-
-    @classmethod
-    def parse_number(cls, name):
-        """
-        Given a migration name, tries to extract a number from the
-        beginning of it. If no number found, returns None.
-        """
-        if re.match(r"^\d+_", name):
-            return int(name.split("_")[0])
-        return None
-
-    @classmethod
-    def arrange_for_graph(cls, changes, graph):
+    def arrange_for_graph(self, changes, graph):
         """
         Takes in a result from changes() and a MigrationGraph,
         and fixes the names and dependencies of the changes so they
@@ -103,7 +79,7 @@ class MigrationAutodetector(object):
         """
         leaves = graph.leaf_nodes()
         name_map = {}
-        for app_label, migrations in changes.items():
+        for app_label, migrations in list(changes.items()):
             if not migrations:
                 continue
             # Find the app label's current leaf node
@@ -112,11 +88,17 @@ class MigrationAutodetector(object):
                 if leaf[0] == app_label:
                     app_leaf = leaf
                     break
+            # Do they want an initial migration for this app?
+            if app_leaf is None and not self.questioner.ask_initial(app_label):
+                # They don't.
+                for migration in migrations:
+                    name_map[(app_label, migration.name)] = (app_label, "__first__")
+                del changes[app_label]
             # Work out the next number in the sequence
             if app_leaf is None:
                 next_number = 1
             else:
-                next_number = (cls.parse_number(app_leaf[1]) or 0) + 1
+                next_number = (self.parse_number(app_leaf[1]) or 0) + 1
             # Name each migration
             for i, migration in enumerate(migrations):
                 if i == 0 and app_leaf:
@@ -124,7 +106,7 @@ class MigrationAutodetector(object):
                 if i == 0 and not app_leaf:
                     new_name = "0001_initial"
                 else:
-                    new_name = "%04i_%s" % (next_number, cls.suggest_name(migration.operations))
+                    new_name = "%04i_%s" % (next_number, self.suggest_name(migration.operations))
                 name_map[(app_label, migration.name)] = (app_label, new_name)
                 migration.name = new_name
         # Now fix dependencies
@@ -132,3 +114,94 @@ class MigrationAutodetector(object):
             for migration in migrations:
                 migration.dependencies = [name_map.get(d, d) for d in migration.dependencies]
         return changes
+
+    def trim_to_apps(self, changes, app_labels):
+        """
+        Takes changes from arrange_for_graph and set of app labels and
+        returns a modified set of changes which trims out as many migrations
+        that are not in app_labels as possible.
+        Note that some other migrations may still be present, as they may be
+        required dependencies.
+        """
+        # Gather other app dependencies in a first pass
+        app_dependencies = {}
+        for app_label, migrations in changes.items():
+            for migration in migrations:
+                for dep_app_label, name in migration.dependencies:
+                    app_dependencies.setdefault(app_label, set()).add(dep_app_label)
+        required_apps = set(app_labels)
+        # Keep resolving till there's no change
+        old_required_apps = None
+        while old_required_apps != required_apps:
+            old_required_apps = set(required_apps)
+            for app_label in list(required_apps):
+                required_apps.update(app_dependencies.get(app_label, set()))
+        # Remove all migrations that aren't needed
+        for app_label in list(changes.keys()):
+            if app_label not in required_apps:
+                del changes[app_label]
+        return changes
+
+    @classmethod
+    def suggest_name(cls, ops):
+        """
+        Given a set of operations, suggests a name for the migration
+        they might represent. Names not guaranteed to be unique; they
+        must be prefixed by a number or date.
+        """
+        if len(ops) == 1:
+            if isinstance(ops[0], operations.CreateModel):
+                return ops[0].name.lower()
+            elif isinstance(ops[0], operations.DeleteModel):
+                return "delete_%s" % ops[0].name.lower()
+        elif all(isinstance(o, operations.CreateModel) for o in ops):
+            return "_".join(sorted(o.name.lower() for o in ops))
+        return "auto"
+
+    @classmethod
+    def parse_number(cls, name):
+        """
+        Given a migration name, tries to extract a number from the
+        beginning of it. If no number found, returns None.
+        """
+        if re.match(r"^\d+_", name):
+            return int(name.split("_")[0])
+        return None
+
+
+class MigrationQuestioner(object):
+    """
+    Gives the autodetector responses to questions it might have.
+    This base class has a built-in noninteractive mode, but the
+    interactive subclass is what the command-line arguments will use.
+    """
+
+    def __init__(self, defaults=None):
+        self.defaults = defaults or {}
+
+    def ask_initial(self, app_label):
+        "Should we create an initial migration for the app?"
+        return self.defaults.get("ask_initial", False)
+
+
+class InteractiveMigrationQuestioner(MigrationQuestioner):
+
+    def __init__(self, specified_apps=set()):
+        self.specified_apps = specified_apps
+
+    def _boolean_input(self, question):
+        result = input("%s " % question)
+        while len(result) < 1 or result[0].lower() not in "yn":
+            result = input("Please answer yes or no: ")
+        return result[0].lower() == "y"
+
+    def ask_initial(self, app_label):
+        # Don't ask for django.contrib apps
+        app = cache.get_app(app_label)
+        if app.__name__.startswith("django.contrib"):
+            return False
+        # If it was specified on the command line, definitely true
+        if app_label in self.specified_apps:
+            return True
+        # Now ask
+        return self._boolean_input("Do you want to enable migrations for app '%s'?" % app_label)
diff --git a/django/db/migrations/graph.py b/django/db/migrations/graph.py
index c1c3ba75bb..1bbe0092ae 100644
--- a/django/db/migrations/graph.py
+++ b/django/db/migrations/graph.py
@@ -49,7 +49,7 @@ class MigrationGraph(object):
         a database.
         """
         if node not in self.nodes:
-            raise ValueError("Node %r not a valid node" % node)
+            raise ValueError("Node %r not a valid node" % (node, ))
         return self.dfs(node, lambda x: self.dependencies.get(x, set()))
 
     def backwards_plan(self, node):
@@ -60,7 +60,7 @@ class MigrationGraph(object):
         a database.
         """
         if node not in self.nodes:
-            raise ValueError("Node %r not a valid node" % node)
+            raise ValueError("Node %r not a valid node" % (node, ))
         return self.dfs(node, lambda x: self.dependents.get(x, set()))
 
     def root_nodes(self):
@@ -120,11 +120,16 @@ class MigrationGraph(object):
     def __str__(self):
         return "Graph: %s nodes, %s edges" % (len(self.nodes), sum(len(x) for x in self.dependencies.values()))
 
-    def project_state(self, nodes, at_end=True):
+    def project_state(self, nodes=None, at_end=True):
         """
         Given a migration node or nodes, returns a complete ProjectState for it.
         If at_end is False, returns the state before the migration has run.
+        If nodes is not provided, returns the overall most current project state.
         """
+        if nodes is None:
+            nodes = list(self.leaf_nodes())
+        if len(nodes) == 0:
+            return ProjectState()
         if not isinstance(nodes[0], tuple):
             nodes = [nodes]
         plan = []
diff --git a/django/db/migrations/recorder.py b/django/db/migrations/recorder.py
index a1f111f2bc..65e4fbbda7 100644
--- a/django/db/migrations/recorder.py
+++ b/django/db/migrations/recorder.py
@@ -60,3 +60,10 @@ class MigrationRecorder(object):
         """
         self.ensure_schema()
         self.Migration.objects.filter(app=app, name=name).delete()
+
+    @classmethod
+    def flush(cls):
+        """
+        Deletes all migration records. Useful if you're testing migrations.
+        """
+        cls.Migration.objects.all().delete()
diff --git a/tests/migrations/test_autodetector.py b/tests/migrations/test_autodetector.py
index 1fc8f7aefb..2b9ce21a1d 100644
--- a/tests/migrations/test_autodetector.py
+++ b/tests/migrations/test_autodetector.py
@@ -1,12 +1,12 @@
 # encoding: utf8
-from django.test import TransactionTestCase
-from django.db.migrations.autodetector import MigrationAutodetector
+from django.test import TestCase
+from django.db.migrations.autodetector import MigrationAutodetector, MigrationQuestioner
 from django.db.migrations.state import ProjectState, ModelState
 from django.db.migrations.graph import MigrationGraph
 from django.db import models
 
 
-class AutodetectorTests(TransactionTestCase):
+class AutodetectorTests(TestCase):
     """
     Tests the migration autodetector.
     """
@@ -14,6 +14,7 @@ class AutodetectorTests(TransactionTestCase):
     author_empty = ModelState("testapp", "Author", [("id", models.AutoField(primary_key=True))])
     other_pony = ModelState("otherapp", "Pony", [("id", models.AutoField(primary_key=True))])
     other_stable = ModelState("otherapp", "Stable", [("id", models.AutoField(primary_key=True))])
+    third_thing = ModelState("thirdapp", "Thing", [("id", models.AutoField(primary_key=True))])
 
     def make_project_state(self, model_states):
         "Shortcut to make ProjectStates from lists of predefined models"
@@ -44,6 +45,23 @@ class AutodetectorTests(TransactionTestCase):
         self.assertEqual(changes["otherapp"][0].name, "0002_pony_stable")
         self.assertEqual(changes["otherapp"][0].dependencies, [("otherapp", "0001_initial")])
 
+    def test_trim_apps(self):
+        "Tests that trim does not remove dependencies but does remove unwanted apps"
+        # Use project state to make a new migration change set
+        before = self.make_project_state([])
+        after = self.make_project_state([self.author_empty, self.other_pony, self.other_stable, self.third_thing])
+        autodetector = MigrationAutodetector(before, after, MigrationQuestioner({"ask_initial": True}))
+        changes = autodetector.changes()
+        # Run through arrange_for_graph
+        graph = MigrationGraph()
+        changes = autodetector.arrange_for_graph(changes, graph)
+        changes["testapp"][0].dependencies.append(("otherapp", "0001_initial"))
+        changes = autodetector.trim_to_apps(changes, set(["testapp"]))
+        # Make sure there's the right set of migrations
+        self.assertEqual(changes["testapp"][0].name, "0001_initial")
+        self.assertEqual(changes["otherapp"][0].name, "0001_initial")
+        self.assertNotIn("thirdapp", changes)
+
     def test_new_model(self):
         "Tests autodetection of new models"
         # Make state
diff --git a/tests/migrations/migrations/0001_initial.py b/tests/migrations/test_migrations/0001_initial.py
index e2ed8559a6..e2ed8559a6 100644
--- a/tests/migrations/migrations/0001_initial.py
+++ b/tests/migrations/test_migrations/0001_initial.py
diff --git a/tests/migrations/migrations/0002_second.py b/tests/migrations/test_migrations/0002_second.py
index ace9a83347..ace9a83347 100644
--- a/tests/migrations/migrations/0002_second.py
+++ b/tests/migrations/test_migrations/0002_second.py
diff --git a/tests/migrations/migrations/__init__.py b/tests/migrations/test_migrations/__init__.py
index e69de29bb2..e69de29bb2 100644
--- a/tests/migrations/migrations/__init__.py
+++ b/tests/migrations/test_migrations/__init__.py
diff --git a/tests/schema/tests.py b/tests/schema/tests.py
index f643f3ed68..89853088ac 100644
--- a/tests/schema/tests.py
+++ b/tests/schema/tests.py
@@ -17,6 +17,8 @@ class SchemaTests(TransactionTestCase):
     as sometimes the code to check if a test has worked is almost as complex
     as the code it is testing.
     """
+    
+    available_apps = []
 
     models = [Author, AuthorWithM2M, Book, BookWithSlug, BookWithM2M, Tag, TagUniqueRename, UniqueTest]
     no_table_strings = ["no such table", "unknown table", "does not exist"]