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Merge pull request #3280 from Markush2010/ticket23556 

Fixed #23556 -- Raise a more meaningful error message when migrations refer to an unavailable node
This commit is contained in:
Andrew Godwin 2014-10-29 17:52:12 -07:00
parent 388c6038fd 85086c8158
commit aac594f65f
19 changed files with 369 additions and 18 deletions
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34
django/db/migrations/graph.py
View File

@ -1,7 +1,7 @@
from __future__ import unicode_literals
from django.utils.datastructures import OrderedSet
from django.db.migrations.state import ProjectState
from django.utils.datastructures import OrderedSet
class MigrationGraph(object):
@ -37,12 +37,14 @@ class MigrationGraph(object):
def add_dependency(self, migration, child, parent):
if child not in self.nodes:
raise KeyError(
"Migration %s dependencies reference nonexistent child node %r" % (migration, child)
raise NodeNotFoundError(
"Migration %s dependencies reference nonexistent child node %r" % (migration, child),
child
)
if parent not in self.nodes:
raise KeyError(
"Migration %s dependencies reference nonexistent parent node %r" % (migration, parent)
raise NodeNotFoundError(
"Migration %s dependencies reference nonexistent parent node %r" % (migration, parent),
parent
)
self.dependencies.setdefault(child, set()).add(parent)
self.dependents.setdefault(parent, set()).add(child)
@ -55,7 +57,7 @@ class MigrationGraph(object):
a database.
"""
if node not in self.nodes:
raise ValueError("Node %r not a valid node" % (node, ))
raise NodeNotFoundError("Node %r not a valid node" % (node, ), node)
return self.dfs(node, lambda x: self.dependencies.get(x, set()))
def backwards_plan(self, node):
@ -66,7 +68,7 @@ class MigrationGraph(object):
a database.
"""
if node not in self.nodes:
raise ValueError("Node %r not a valid node" % (node, ))
raise NodeNotFoundError("Node %r not a valid node" % (node, ), node)
return self.dfs(node, lambda x: self.dependents.get(x, set()))
def root_nodes(self, app=None):
@ -160,3 +162,21 @@ class CircularDependencyError(Exception):
Raised when there's an impossible-to-resolve circular dependency.
"""
pass
class NodeNotFoundError(LookupError):
"""
Raised when an attempt on a node is made that is not available in the graph.
"""
def __init__(self, message, node):
self.message = message
self.node = node
def __str__(self):
return self.message
__unicode__ = __str__
def __repr__(self):
return "NodeNotFoundError(%r)" % self.node

56
django/db/migrations/loader.py
View File

@ -6,7 +6,7 @@ import sys
from django.apps import apps
from django.db.migrations.recorder import MigrationRecorder
from django.db.migrations.graph import MigrationGraph
from django.db.migrations.graph import MigrationGraph, NodeNotFoundError
from django.utils import six
from django.conf import settings
@ -118,7 +118,7 @@ class MigrationLoader(object):
self.unmigrated_apps.add(app_config.label)
def get_migration(self, app_label, name_prefix):
"Gets the migration exactly named, or raises KeyError"
"Gets the migration exactly named, or raises `graph.NodeNotFoundError`"
return self.graph.nodes[app_label, name_prefix]
def get_migration_by_prefix(self, app_label, name_prefix):
@ -156,7 +156,7 @@ class MigrationLoader(object):
try:
if key[1] == "__first__":
return list(self.graph.root_nodes(key[0]))[0]
else:
else: # "__latest__"
return list(self.graph.leaf_nodes(key[0]))[0]
except IndexError:
if self.ignore_no_migrations:
@ -194,6 +194,12 @@ class MigrationLoader(object):
for key, migration in normal.items():
for parent in migration.dependencies:
reverse_dependencies.setdefault(parent, set()).add(key)
# Remeber the possible replacements to generate more meaningful error
# messages
reverse_replacements = {}
for key, migration in replacing.items():
for replaced in migration.replaces:
reverse_replacements.setdefault(replaced, set()).add(key)
# Carry out replacements if we can - that is, if all replaced migrations
# are either unapplied or missing.
for key, migration in replacing.items():
@ -225,6 +231,32 @@ class MigrationLoader(object):
self.graph = MigrationGraph()
for key, migration in normal.items():
self.graph.add_node(key, migration)
def _reraise_missing_dependency(migration, missing, exc):
"""
Checks if ``missing`` could have been replaced by any squash
migration but wasn't because the the squash migration was partially
applied before. In that case raise a more understandable exception.
#23556
"""
if missing in reverse_replacements:
candidates = reverse_replacements.get(missing, set())
is_replaced = any(candidate in self.graph.nodes for candidate in candidates)
if not is_replaced:
tries = ', '.join('%s.%s' % c for c in candidates)
exc_value = NodeNotFoundError(
"Migration {0} depends on nonexistent node ('{1}', '{2}'). "
"Django tried to replace migration {1}.{2} with any of [{3}] "
"but wasn't able to because some of the replaced migrations "
"are already applied.".format(
migration, missing[0], missing[1], tries
),
missing)
exc_value.__cause__ = exc
six.reraise(NodeNotFoundError, exc_value, sys.exc_info()[2])
raise exc
# Add all internal dependencies first to ensure __first__ dependencies
# find the correct root node.
for key, migration in normal.items():
@ -232,7 +264,15 @@ class MigrationLoader(object):
if parent[0] != key[0] or parent[1] == '__first__':
# Ignore __first__ references to the same app (#22325)
continue
try:
self.graph.add_dependency(migration, key, parent)
except NodeNotFoundError as e:
# Since we added "key" to the nodes before this implies
# "parent" is not in there. To make the raised exception
# more understandable we check if parent could have been
# replaced but hasn't (eg partially applied squashed
# migration)
_reraise_missing_dependency(migration, parent, e)
for key, migration in normal.items():
for parent in migration.dependencies:
if parent[0] == key[0]:
@ -240,11 +280,21 @@ class MigrationLoader(object):
continue
parent = self.check_key(parent, key[0])
if parent is not None:
try:
self.graph.add_dependency(migration, key, parent)
except NodeNotFoundError as e:
# Since we added "key" to the nodes before this implies
# "parent" is not in there.
_reraise_missing_dependency(migration, parent, e)
for child in migration.run_before:
child = self.check_key(child, key[0])
if child is not None:
try:
self.graph.add_dependency(migration, child, key)
except NodeNotFoundError as e:
# Since we added "key" to the nodes before this implies
# "child" is not in there.
_reraise_missing_dependency(migration, child, e)
def detect_conflicts(self):
"""

10
tests/migrations/test_graph.py
View File

@ -1,5 +1,5 @@
from django.test import TestCase
from django.db.migrations.graph import MigrationGraph, CircularDependencyError
from django.db.migrations.graph import CircularDependencyError, MigrationGraph, NodeNotFoundError
class GraphTests(TestCase):
@ -156,10 +156,10 @@ class GraphTests(TestCase):
graph = MigrationGraph()
message = "Node ('app_b', '0001') not a valid node"
with self.assertRaisesMessage(ValueError, message):
with self.assertRaisesMessage(NodeNotFoundError, message):
graph.forwards_plan(("app_b", "0001"))
with self.assertRaisesMessage(ValueError, message):
with self.assertRaisesMessage(NodeNotFoundError, message):
graph.backwards_plan(("app_b", "0001"))
def test_missing_parent_nodes(self):
@ -175,7 +175,7 @@ class GraphTests(TestCase):
graph.add_dependency("app_a.0003", ("app_a", "0003"), ("app_a", "0002"))
graph.add_dependency("app_a.0002", ("app_a", "0002"), ("app_a", "0001"))
msg = "Migration app_a.0001 dependencies reference nonexistent parent node ('app_b', '0002')"
with self.assertRaisesMessage(KeyError, msg):
with self.assertRaisesMessage(NodeNotFoundError, msg):
graph.add_dependency("app_a.0001", ("app_a", "0001"), ("app_b", "0002"))
def test_missing_child_nodes(self):
@ -186,5 +186,5 @@ class GraphTests(TestCase):
graph = MigrationGraph()
graph.add_node(("app_a", "0001"), None)
msg = "Migration app_a.0002 dependencies reference nonexistent child node ('app_a', '0002')"
with self.assertRaisesMessage(KeyError, msg):
with self.assertRaisesMessage(NodeNotFoundError, msg):
graph.add_dependency("app_a.0002", ("app_a", "0002"), ("app_a", "0001"))

104
tests/migrations/test_loader.py
View File

@ -1,7 +1,10 @@
from __future__ import unicode_literals
from unittest import skipIf
from django.test import TestCase, override_settings
from django.db import connection, connections
from django.db.migrations.graph import NodeNotFoundError
from django.db.migrations.loader import MigrationLoader, AmbiguityError
from django.db.migrations.recorder import MigrationRecorder
from django.test import modify_settings
@ -187,3 +190,104 @@ class LoaderTests(TestCase):
2,
)
recorder.flush()
@override_settings(MIGRATION_MODULES={"migrations": "migrations.test_migrations_squashed_complex"})
def test_loading_squashed_complex(self):
"Tests loading a complex set of squashed migrations"
loader = MigrationLoader(connection)
recorder = MigrationRecorder(connection)
def num_nodes():
plan = set(loader.graph.forwards_plan(('migrations', '7_auto')))
return len(plan - loader.applied_migrations)
# Empty database: use squashed migration
loader.build_graph()
self.assertEqual(num_nodes(), 5)
# Starting at 1 or 2 should use the squashed migration too
recorder.record_applied("migrations", "1_auto")
loader.build_graph()
self.assertEqual(num_nodes(), 4)
recorder.record_applied("migrations", "2_auto")
loader.build_graph()
self.assertEqual(num_nodes(), 3)
# However, starting at 3 to 5 cannot use the squashed migration
recorder.record_applied("migrations", "3_auto")
loader.build_graph()
self.assertEqual(num_nodes(), 4)
recorder.record_applied("migrations", "4_auto")
loader.build_graph()
self.assertEqual(num_nodes(), 3)
# Starting at 5 to 7 we are passed the squashed migrations
recorder.record_applied("migrations", "5_auto")
loader.build_graph()
self.assertEqual(num_nodes(), 2)
recorder.record_applied("migrations", "6_auto")
loader.build_graph()
self.assertEqual(num_nodes(), 1)
recorder.record_applied("migrations", "7_auto")
loader.build_graph()
self.assertEqual(num_nodes(), 0)
recorder.flush()
@override_settings(MIGRATION_MODULES={"migrations": "migrations.test_migrations_squashed_erroneous"})
def test_loading_squashed_erroneous(self):
"Tests loading a complex but erroneous set of squashed migrations"
loader = MigrationLoader(connection)
recorder = MigrationRecorder(connection)
def num_nodes():
plan = set(loader.graph.forwards_plan(('migrations', '7_auto')))
return len(plan - loader.applied_migrations)
# Empty database: use squashed migration
loader.build_graph()
self.assertEqual(num_nodes(), 5)
# Starting at 1 or 2 should use the squashed migration too
recorder.record_applied("migrations", "1_auto")
loader.build_graph()
self.assertEqual(num_nodes(), 4)
recorder.record_applied("migrations", "2_auto")
loader.build_graph()
self.assertEqual(num_nodes(), 3)
# However, starting at 3 or 4 we'd need to use non-existing migrations
msg = ("Migration migrations.6_auto depends on nonexistent node ('migrations', '5_auto'). "
"Django tried to replace migration migrations.5_auto with any of "
"[migrations.3_squashed_5] but wasn't able to because some of the replaced "
"migrations are already applied.")
recorder.record_applied("migrations", "3_auto")
with self.assertRaisesMessage(NodeNotFoundError, msg):
loader.build_graph()
recorder.record_applied("migrations", "4_auto")
with self.assertRaisesMessage(NodeNotFoundError, msg):
loader.build_graph()
# Starting at 5 to 7 we are passed the squashed migrations
recorder.record_applied("migrations", "5_auto")
loader.build_graph()
self.assertEqual(num_nodes(), 2)
recorder.record_applied("migrations", "6_auto")
loader.build_graph()
self.assertEqual(num_nodes(), 1)
recorder.record_applied("migrations", "7_auto")
loader.build_graph()
self.assertEqual(num_nodes(), 0)
recorder.flush()

11
tests/migrations/test_migrations_squashed_complex/1_auto.py Normal file
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@ -0,0 +1,11 @@
# -*- coding: utf-8 -*-
from __future__ import unicode_literals
from django.db import migrations
class Migration(migrations.Migration):
operations = [
migrations.RunPython(lambda apps, schema_editor: None)
]

13
tests/migrations/test_migrations_squashed_complex/2_auto.py Normal file
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@ -0,0 +1,13 @@
# -*- coding: utf-8 -*-
from __future__ import unicode_literals
from django.db import migrations
class Migration(migrations.Migration):
dependencies = [("migrations", "1_auto")]
operations = [
migrations.RunPython(lambda apps, schema_editor: None)
]

13
tests/migrations/test_migrations_squashed_complex/3_auto.py Normal file
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@ -0,0 +1,13 @@
# -*- coding: utf-8 -*-
from __future__ import unicode_literals
from django.db import migrations
class Migration(migrations.Migration):
dependencies = [("migrations", "2_auto")]
operations = [
migrations.RunPython(lambda apps, schema_editor: None)
]

19
tests/migrations/test_migrations_squashed_complex/3_squashed_5.py Normal file
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@ -0,0 +1,19 @@
# -*- coding: utf-8 -*-
from __future__ import unicode_literals
from django.db import migrations
class Migration(migrations.Migration):
replaces = [
("migrations", "3_auto"),
("migrations", "4_auto"),
("migrations", "5_auto"),
]
dependencies = [("migrations", "2_auto")]
operations = [
migrations.RunPython(lambda apps, schema_editor: None)
]

13
tests/migrations/test_migrations_squashed_complex/4_auto.py Normal file
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@ -0,0 +1,13 @@
# -*- coding: utf-8 -*-
from __future__ import unicode_literals
from django.db import migrations
class Migration(migrations.Migration):
dependencies = [("migrations", "3_auto")]
operations = [
migrations.RunPython(lambda apps, schema_editor: None)
]

13
tests/migrations/test_migrations_squashed_complex/5_auto.py Normal file
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@ -0,0 +1,13 @@
# -*- coding: utf-8 -*-
from __future__ import unicode_literals
from django.db import migrations
class Migration(migrations.Migration):
dependencies = [("migrations", "4_auto")]
operations = [
migrations.RunPython(lambda apps, schema_editor: None)
]

13
tests/migrations/test_migrations_squashed_complex/6_auto.py Normal file
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@ -0,0 +1,13 @@
# -*- coding: utf-8 -*-
from __future__ import unicode_literals
from django.db import migrations
class Migration(migrations.Migration):
dependencies = [("migrations", "5_auto")]
operations = [
migrations.RunPython(lambda apps, schema_editor: None)
]

13
tests/migrations/test_migrations_squashed_complex/7_auto.py Normal file
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@ -0,0 +1,13 @@
# -*- coding: utf-8 -*-
from __future__ import unicode_literals
from django.db import migrations
class Migration(migrations.Migration):
dependencies = [("migrations", "6_auto")]
operations = [
migrations.RunPython(lambda apps, schema_editor: None)
]

0
tests/migrations/test_migrations_squashed_complex/__init__.py Normal file
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11
tests/migrations/test_migrations_squashed_erroneous/1_auto.py Normal file
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@ -0,0 +1,11 @@
# -*- coding: utf-8 -*-
from __future__ import unicode_literals
from django.db import migrations
class Migration(migrations.Migration):
operations = [
migrations.RunPython(lambda apps, schema_editor: None)
]

13
tests/migrations/test_migrations_squashed_erroneous/2_auto.py Normal file
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@ -0,0 +1,13 @@
# -*- coding: utf-8 -*-
from __future__ import unicode_literals
from django.db import migrations
class Migration(migrations.Migration):
dependencies = [("migrations", "1_auto")]
operations = [
migrations.RunPython(lambda apps, schema_editor: None)
]

19
tests/migrations/test_migrations_squashed_erroneous/3_squashed_5.py Normal file
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@ -0,0 +1,19 @@
# -*- coding: utf-8 -*-
from __future__ import unicode_literals
from django.db import migrations
class Migration(migrations.Migration):
replaces = [
("migrations", "3_auto"),
("migrations", "4_auto"),
("migrations", "5_auto"),
]
dependencies = [("migrations", "2_auto")]
operations = [
migrations.RunPython(lambda apps, schema_editor: None)
]

13
tests/migrations/test_migrations_squashed_erroneous/6_auto.py Normal file
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@ -0,0 +1,13 @@
# -*- coding: utf-8 -*-
from __future__ import unicode_literals
from django.db import migrations
class Migration(migrations.Migration):
dependencies = [("migrations", "5_auto")]
operations = [
migrations.RunPython(lambda apps, schema_editor: None)
]

13
tests/migrations/test_migrations_squashed_erroneous/7_auto.py Normal file
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@ -0,0 +1,13 @@
# -*- coding: utf-8 -*-
from __future__ import unicode_literals
from django.db import migrations
class Migration(migrations.Migration):
dependencies = [("migrations", "6_auto")]
operations = [
migrations.RunPython(lambda apps, schema_editor: None)
]

0
tests/migrations/test_migrations_squashed_erroneous/__init__.py Normal file
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