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from __future__ import annotations
import contextlib
import logging
import re
from typing import Any
from typing import cast
from typing import Dict
from typing import Iterator
from typing import List
from typing import Mapping
from typing import Optional
from typing import Set
from typing import Tuple
from typing import TYPE_CHECKING
from typing import Union
from sqlalchemy import event
from sqlalchemy import inspect
from sqlalchemy import schema as sa_schema
from sqlalchemy import text
from sqlalchemy import types as sqltypes
from sqlalchemy.sql import expression
from sqlalchemy.util import OrderedSet
from alembic.ddl.base import _fk_spec
from .. import util
from ..operations import ops
from ..util import sqla_compat
if TYPE_CHECKING:
from typing import Literal
from sqlalchemy.engine.reflection import Inspector
from sqlalchemy.sql.elements import quoted_name
from sqlalchemy.sql.elements import TextClause
from sqlalchemy.sql.schema import Column
from sqlalchemy.sql.schema import ForeignKeyConstraint
from sqlalchemy.sql.schema import Index
from sqlalchemy.sql.schema import Table
from sqlalchemy.sql.schema import UniqueConstraint
from alembic.autogenerate.api import AutogenContext
from alembic.ddl.impl import DefaultImpl
from alembic.operations.ops import AlterColumnOp
from alembic.operations.ops import MigrationScript
from alembic.operations.ops import ModifyTableOps
from alembic.operations.ops import UpgradeOps
log = logging.getLogger(__name__)
def _populate_migration_script(
autogen_context: AutogenContext, migration_script: MigrationScript
) -> None:
upgrade_ops = migration_script.upgrade_ops_list[-1]
downgrade_ops = migration_script.downgrade_ops_list[-1]
_produce_net_changes(autogen_context, upgrade_ops)
upgrade_ops.reverse_into(downgrade_ops)
comparators = util.Dispatcher(uselist=True)
def _produce_net_changes(
autogen_context: AutogenContext, upgrade_ops: UpgradeOps
) -> None:
connection = autogen_context.connection
assert connection is not None
include_schemas = autogen_context.opts.get("include_schemas", False)
inspector: Inspector = inspect(connection)
default_schema = connection.dialect.default_schema_name
schemas: Set[Optional[str]]
if include_schemas:
schemas = set(inspector.get_schema_names())
# replace default schema name with None
schemas.discard("information_schema")
# replace the "default" schema with None
schemas.discard(default_schema)
schemas.add(None)
else:
schemas = {None}
schemas = {
s for s in schemas if autogen_context.run_name_filters(s, "schema", {})
}
assert autogen_context.dialect is not None
comparators.dispatch("schema", autogen_context.dialect.name)(
autogen_context, upgrade_ops, schemas
)
@comparators.dispatch_for("schema")
def _autogen_for_tables(
autogen_context: AutogenContext,
upgrade_ops: UpgradeOps,
schemas: Union[Set[None], Set[Optional[str]]],
) -> None:
inspector = autogen_context.inspector
conn_table_names: Set[Tuple[Optional[str], str]] = set()
version_table_schema = (
autogen_context.migration_context.version_table_schema
)
version_table = autogen_context.migration_context.version_table
for schema_name in schemas:
tables = set(inspector.get_table_names(schema=schema_name))
if schema_name == version_table_schema:
tables = tables.difference(
[autogen_context.migration_context.version_table]
)
conn_table_names.update(
(schema_name, tname)
for tname in tables
if autogen_context.run_name_filters(
tname, "table", {"schema_name": schema_name}
)
)
metadata_table_names = OrderedSet(
[(table.schema, table.name) for table in autogen_context.sorted_tables]
).difference([(version_table_schema, version_table)])
_compare_tables(
conn_table_names,
metadata_table_names,
inspector,
upgrade_ops,
autogen_context,
)
def _compare_tables(
conn_table_names: set,
metadata_table_names: set,
inspector: Inspector,
upgrade_ops: UpgradeOps,
autogen_context: AutogenContext,
) -> None:
default_schema = inspector.bind.dialect.default_schema_name
# tables coming from the connection will not have "schema"
# set if it matches default_schema_name; so we need a list
# of table names from local metadata that also have "None" if schema
# == default_schema_name. Most setups will be like this anyway but
# some are not (see #170)
metadata_table_names_no_dflt_schema = OrderedSet(
[
(schema if schema != default_schema else None, tname)
for schema, tname in metadata_table_names
]
)
# to adjust for the MetaData collection storing the tables either
# as "schemaname.tablename" or just "tablename", create a new lookup
# which will match the "non-default-schema" keys to the Table object.
tname_to_table = {
no_dflt_schema: autogen_context.table_key_to_table[
sa_schema._get_table_key(tname, schema)
]
for no_dflt_schema, (schema, tname) in zip(
metadata_table_names_no_dflt_schema, metadata_table_names
)
}
metadata_table_names = metadata_table_names_no_dflt_schema
for s, tname in metadata_table_names.difference(conn_table_names):
name = "%s.%s" % (s, tname) if s else tname
metadata_table = tname_to_table[(s, tname)]
if autogen_context.run_object_filters(
metadata_table, tname, "table", False, None
):
upgrade_ops.ops.append(
ops.CreateTableOp.from_table(metadata_table)
)
log.info("Detected added table %r", name)
modify_table_ops = ops.ModifyTableOps(tname, [], schema=s)
comparators.dispatch("table")(
autogen_context,
modify_table_ops,
s,
tname,
None,
metadata_table,
)
if not modify_table_ops.is_empty():
upgrade_ops.ops.append(modify_table_ops)
removal_metadata = sa_schema.MetaData()
for s, tname in conn_table_names.difference(metadata_table_names):
name = sa_schema._get_table_key(tname, s)
exists = name in removal_metadata.tables
t = sa_schema.Table(tname, removal_metadata, schema=s)
if not exists:
event.listen(
t,
"column_reflect",
# fmt: off
autogen_context.migration_context.impl.
_compat_autogen_column_reflect
(inspector),
# fmt: on
)
sqla_compat._reflect_table(inspector, t)
if autogen_context.run_object_filters(t, tname, "table", True, None):
modify_table_ops = ops.ModifyTableOps(tname, [], schema=s)
comparators.dispatch("table")(
autogen_context, modify_table_ops, s, tname, t, None
)
if not modify_table_ops.is_empty():
upgrade_ops.ops.append(modify_table_ops)
upgrade_ops.ops.append(ops.DropTableOp.from_table(t))
log.info("Detected removed table %r", name)
existing_tables = conn_table_names.intersection(metadata_table_names)
existing_metadata = sa_schema.MetaData()
conn_column_info = {}
for s, tname in existing_tables:
name = sa_schema._get_table_key(tname, s)
exists = name in existing_metadata.tables
t = sa_schema.Table(tname, existing_metadata, schema=s)
if not exists:
event.listen(
t,
"column_reflect",
# fmt: off
autogen_context.migration_context.impl.
_compat_autogen_column_reflect(inspector),
# fmt: on
)
sqla_compat._reflect_table(inspector, t)
conn_column_info[(s, tname)] = t
for s, tname in sorted(existing_tables, key=lambda x: (x[0] or "", x[1])):
s = s or None
name = "%s.%s" % (s, tname) if s else tname
metadata_table = tname_to_table[(s, tname)]
conn_table = existing_metadata.tables[name]
if autogen_context.run_object_filters(
metadata_table, tname, "table", False, conn_table
):
modify_table_ops = ops.ModifyTableOps(tname, [], schema=s)
with _compare_columns(
s,
tname,
conn_table,
metadata_table,
modify_table_ops,
autogen_context,
inspector,
):
comparators.dispatch("table")(
autogen_context,
modify_table_ops,
s,
tname,
conn_table,
metadata_table,
)
if not modify_table_ops.is_empty():
upgrade_ops.ops.append(modify_table_ops)
_IndexColumnSortingOps: Mapping[str, Any] = util.immutabledict(
{
"asc": expression.asc,
"desc": expression.desc,
"nulls_first": expression.nullsfirst,
"nulls_last": expression.nullslast,
"nullsfirst": expression.nullsfirst, # 1_3 name
"nullslast": expression.nullslast, # 1_3 name
}
)
def _make_index(params: Dict[str, Any], conn_table: Table) -> Optional[Index]:
exprs: list[Union[Column[Any], TextClause]] = []
sorting = params.get("column_sorting")
for num, col_name in enumerate(params["column_names"]):
item: Union[Column[Any], TextClause]
if col_name is None:
assert "expressions" in params
name = params["expressions"][num]
item = text(name)
else:
name = col_name
item = conn_table.c[col_name]
if sorting and name in sorting:
for operator in sorting[name]:
if operator in _IndexColumnSortingOps:
item = _IndexColumnSortingOps[operator](item)
exprs.append(item)
ix = sa_schema.Index(
params["name"], *exprs, unique=params["unique"], _table=conn_table
)
if "duplicates_constraint" in params:
ix.info["duplicates_constraint"] = params["duplicates_constraint"]
return ix
def _make_unique_constraint(
params: Dict[str, Any], conn_table: Table
) -> UniqueConstraint:
uq = sa_schema.UniqueConstraint(
*[conn_table.c[cname] for cname in params["column_names"]],
name=params["name"],
)
if "duplicates_index" in params:
uq.info["duplicates_index"] = params["duplicates_index"]
return uq
def _make_foreign_key(
params: Dict[str, Any], conn_table: Table
) -> ForeignKeyConstraint:
tname = params["referred_table"]
if params["referred_schema"]:
tname = "%s.%s" % (params["referred_schema"], tname)
options = params.get("options", {})
const = sa_schema.ForeignKeyConstraint(
[conn_table.c[cname] for cname in params["constrained_columns"]],
["%s.%s" % (tname, n) for n in params["referred_columns"]],
onupdate=options.get("onupdate"),
ondelete=options.get("ondelete"),
deferrable=options.get("deferrable"),
initially=options.get("initially"),
name=params["name"],
)
# needed by 0.7
conn_table.append_constraint(const)
return const
@contextlib.contextmanager
def _compare_columns(
schema: Optional[str],
tname: Union[quoted_name, str],
conn_table: Table,
metadata_table: Table,
modify_table_ops: ModifyTableOps,
autogen_context: AutogenContext,
inspector: Inspector,
) -> Iterator[None]:
name = "%s.%s" % (schema, tname) if schema else tname
metadata_col_names = OrderedSet(
c.name for c in metadata_table.c if not c.system
)
metadata_cols_by_name = {
c.name: c for c in metadata_table.c if not c.system
}
conn_col_names = {
c.name: c
for c in conn_table.c
if autogen_context.run_name_filters(
c.name, "column", {"table_name": tname, "schema_name": schema}
)
}
for cname in metadata_col_names.difference(conn_col_names):
if autogen_context.run_object_filters(
metadata_cols_by_name[cname], cname, "column", False, None
):
modify_table_ops.ops.append(
ops.AddColumnOp.from_column_and_tablename(
schema, tname, metadata_cols_by_name[cname]
)
)
log.info("Detected added column '%s.%s'", name, cname)
for colname in metadata_col_names.intersection(conn_col_names):
metadata_col = metadata_cols_by_name[colname]
conn_col = conn_table.c[colname]
if not autogen_context.run_object_filters(
metadata_col, colname, "column", False, conn_col
):
continue
alter_column_op = ops.AlterColumnOp(tname, colname, schema=schema)
comparators.dispatch("column")(
autogen_context,
alter_column_op,
schema,
tname,
colname,
conn_col,
metadata_col,
)
if alter_column_op.has_changes():
modify_table_ops.ops.append(alter_column_op)
yield
for cname in set(conn_col_names).difference(metadata_col_names):
if autogen_context.run_object_filters(
conn_table.c[cname], cname, "column", True, None
):
modify_table_ops.ops.append(
ops.DropColumnOp.from_column_and_tablename(
schema, tname, conn_table.c[cname]
)
)
log.info("Detected removed column '%s.%s'", name, cname)
class _constraint_sig:
const: Union[UniqueConstraint, ForeignKeyConstraint, Index]
def md_name_to_sql_name(self, context: AutogenContext) -> Optional[str]:
return sqla_compat._get_constraint_final_name(
self.const, context.dialect
)
def __eq__(self, other):
return self.const == other.const
def __ne__(self, other):
return self.const != other.const
def __hash__(self) -> int:
return hash(self.const)
class _uq_constraint_sig(_constraint_sig):
is_index = False
is_unique = True
def __init__(self, const: UniqueConstraint) -> None:
self.const = const
self.name = const.name
self.sig = ("UNIQUE_CONSTRAINT",) + tuple(
sorted([col.name for col in const.columns])
)
@property
def column_names(self) -> List[str]:
return [col.name for col in self.const.columns]
class _ix_constraint_sig(_constraint_sig):
is_index = True
def __init__(self, const: Index, impl: DefaultImpl) -> None:
self.const = const
self.name = const.name
self.sig = ("INDEX",) + impl.create_index_sig(const)
self.is_unique = bool(const.unique)
def md_name_to_sql_name(self, context: AutogenContext) -> Optional[str]:
return sqla_compat._get_constraint_final_name(
self.const, context.dialect
)
@property
def column_names(self) -> Union[List[quoted_name], List[None]]:
return sqla_compat._get_index_column_names(self.const)
class _fk_constraint_sig(_constraint_sig):
def __init__(
self, const: ForeignKeyConstraint, include_options: bool = False
) -> None:
self.const = const
self.name = const.name
(
self.source_schema,
self.source_table,
self.source_columns,
self.target_schema,
self.target_table,
self.target_columns,
onupdate,
ondelete,
deferrable,
initially,
) = _fk_spec(const)
self.sig: Tuple[Any, ...] = (
self.source_schema,
self.source_table,
tuple(self.source_columns),
self.target_schema,
self.target_table,
tuple(self.target_columns),
)
if include_options:
self.sig += (
(None if onupdate.lower() == "no action" else onupdate.lower())
if onupdate
else None,
(None if ondelete.lower() == "no action" else ondelete.lower())
if ondelete
else None,
# convert initially + deferrable into one three-state value
"initially_deferrable"
if initially and initially.lower() == "deferred"
else "deferrable"
if deferrable
else "not deferrable",
)
@comparators.dispatch_for("table")
def _compare_indexes_and_uniques(
autogen_context: AutogenContext,
modify_ops: ModifyTableOps,
schema: Optional[str],
tname: Union[quoted_name, str],
conn_table: Optional[Table],
metadata_table: Optional[Table],
) -> None:
inspector = autogen_context.inspector
is_create_table = conn_table is None
is_drop_table = metadata_table is None
# 1a. get raw indexes and unique constraints from metadata ...
if metadata_table is not None:
metadata_unique_constraints = {
uq
for uq in metadata_table.constraints
if isinstance(uq, sa_schema.UniqueConstraint)
}
metadata_indexes = set(metadata_table.indexes)
else:
metadata_unique_constraints = set()
metadata_indexes = set()
conn_uniques = conn_indexes = frozenset() # type:ignore[var-annotated]
supports_unique_constraints = False
unique_constraints_duplicate_unique_indexes = False
if conn_table is not None:
# 1b. ... and from connection, if the table exists
if hasattr(inspector, "get_unique_constraints"):
try:
conn_uniques = inspector.get_unique_constraints( # type:ignore[assignment] # noqa
tname, schema=schema
)
supports_unique_constraints = True
except NotImplementedError:
pass
except TypeError:
# number of arguments is off for the base
# method in SQLAlchemy due to the cache decorator
# not being present
pass
else:
conn_uniques = [ # type:ignore[assignment]
uq
for uq in conn_uniques
if autogen_context.run_name_filters(
uq["name"],
"unique_constraint",
{"table_name": tname, "schema_name": schema},
)
]
for uq in conn_uniques:
if uq.get("duplicates_index"):
unique_constraints_duplicate_unique_indexes = True
try:
conn_indexes = inspector.get_indexes( # type:ignore[assignment]
tname, schema=schema
)
except NotImplementedError:
pass
else:
conn_indexes = [ # type:ignore[assignment]
ix
for ix in conn_indexes
if autogen_context.run_name_filters(
ix["name"],
"index",
{"table_name": tname, "schema_name": schema},
)
]
# 2. convert conn-level objects from raw inspector records
# into schema objects
if is_drop_table:
# for DROP TABLE uniques are inline, don't need them
conn_uniques = set() # type:ignore[assignment]
else:
conn_uniques = { # type:ignore[assignment]
_make_unique_constraint(uq_def, conn_table)
for uq_def in conn_uniques
}
conn_indexes = { # type:ignore[assignment]
index
for index in (_make_index(ix, conn_table) for ix in conn_indexes)
if index is not None
}
# 2a. if the dialect dupes unique indexes as unique constraints
# (mysql and oracle), correct for that
if unique_constraints_duplicate_unique_indexes:
_correct_for_uq_duplicates_uix(
conn_uniques,
conn_indexes,
metadata_unique_constraints,
metadata_indexes,
autogen_context.dialect,
)
# 3. give the dialect a chance to omit indexes and constraints that
# we know are either added implicitly by the DB or that the DB
# can't accurately report on
autogen_context.migration_context.impl.correct_for_autogen_constraints(
conn_uniques, # type: ignore[arg-type]
conn_indexes, # type: ignore[arg-type]
metadata_unique_constraints,
metadata_indexes,
)
# 4. organize the constraints into "signature" collections, the
# _constraint_sig() objects provide a consistent facade over both
# Index and UniqueConstraint so we can easily work with them
# interchangeably
metadata_unique_constraints_sig = {
_uq_constraint_sig(uq) for uq in metadata_unique_constraints
}
impl = autogen_context.migration_context.impl
metadata_indexes_sig = {
_ix_constraint_sig(ix, impl) for ix in metadata_indexes
}
conn_unique_constraints = {_uq_constraint_sig(uq) for uq in conn_uniques}
conn_indexes_sig = {_ix_constraint_sig(ix, impl) for ix in conn_indexes}
# 5. index things by name, for those objects that have names
metadata_names = {
cast(str, c.md_name_to_sql_name(autogen_context)): c
for c in metadata_unique_constraints_sig.union(
metadata_indexes_sig # type:ignore[arg-type]
)
if isinstance(c, _ix_constraint_sig)
or sqla_compat._constraint_is_named(c.const, autogen_context.dialect)
}
conn_uniques_by_name: Dict[sqla_compat._ConstraintName, _uq_constraint_sig]
conn_indexes_by_name: Dict[sqla_compat._ConstraintName, _ix_constraint_sig]
conn_uniques_by_name = {c.name: c for c in conn_unique_constraints}
conn_indexes_by_name = {c.name: c for c in conn_indexes_sig}
conn_names = {
c.name: c
for c in conn_unique_constraints.union(conn_indexes_sig)
if sqla_compat.constraint_name_string(c.name)
}
doubled_constraints = {
name: (conn_uniques_by_name[name], conn_indexes_by_name[name])
for name in set(conn_uniques_by_name).intersection(
conn_indexes_by_name
)
}
# 6. index things by "column signature", to help with unnamed unique
# constraints.
conn_uniques_by_sig = {uq.sig: uq for uq in conn_unique_constraints}
metadata_uniques_by_sig = {
uq.sig: uq for uq in metadata_unique_constraints_sig
}
metadata_indexes_by_sig = {ix.sig: ix for ix in metadata_indexes_sig}
unnamed_metadata_uniques = {
uq.sig: uq
for uq in metadata_unique_constraints_sig
if not sqla_compat._constraint_is_named(
uq.const, autogen_context.dialect
)
}
# assumptions:
# 1. a unique constraint or an index from the connection *always*
# has a name.
# 2. an index on the metadata side *always* has a name.
# 3. a unique constraint on the metadata side *might* have a name.
# 4. The backend may double up indexes as unique constraints and
# vice versa (e.g. MySQL, Postgresql)
def obj_added(obj):
if obj.is_index:
if autogen_context.run_object_filters(
obj.const, obj.name, "index", False, None
):
modify_ops.ops.append(ops.CreateIndexOp.from_index(obj.const))
log.info(
"Detected added index '%s' on %s",
obj.name,
", ".join(["'%s'" % obj.column_names]),
)
else:
if not supports_unique_constraints:
# can't report unique indexes as added if we don't
# detect them
return
if is_create_table or is_drop_table:
# unique constraints are created inline with table defs
return
if autogen_context.run_object_filters(
obj.const, obj.name, "unique_constraint", False, None
):
modify_ops.ops.append(
ops.AddConstraintOp.from_constraint(obj.const)
)
log.info(
"Detected added unique constraint '%s' on %s",
obj.name,
", ".join(["'%s'" % obj.column_names]),
)
def obj_removed(obj):
if obj.is_index:
if obj.is_unique and not supports_unique_constraints:
# many databases double up unique constraints
# as unique indexes. without that list we can't
# be sure what we're doing here
return
if autogen_context.run_object_filters(
obj.const, obj.name, "index", True, None
):
modify_ops.ops.append(ops.DropIndexOp.from_index(obj.const))
log.info(
"Detected removed index '%s' on '%s'", obj.name, tname
)
else:
if is_create_table or is_drop_table:
# if the whole table is being dropped, we don't need to
# consider unique constraint separately
return
if autogen_context.run_object_filters(
obj.const, obj.name, "unique_constraint", True, None
):
modify_ops.ops.append(
ops.DropConstraintOp.from_constraint(obj.const)
)
log.info(
"Detected removed unique constraint '%s' on '%s'",
obj.name,
tname,
)
def obj_changed(old, new, msg):
if old.is_index:
if autogen_context.run_object_filters(
new.const, new.name, "index", False, old.const
):
log.info(
"Detected changed index '%s' on '%s':%s",
old.name,
tname,
", ".join(msg),
)
modify_ops.ops.append(ops.DropIndexOp.from_index(old.const))
modify_ops.ops.append(ops.CreateIndexOp.from_index(new.const))
else:
if autogen_context.run_object_filters(
new.const, new.name, "unique_constraint", False, old.const
):
log.info(
"Detected changed unique constraint '%s' on '%s':%s",
old.name,
tname,
", ".join(msg),
)
modify_ops.ops.append(
ops.DropConstraintOp.from_constraint(old.const)
)
modify_ops.ops.append(
ops.AddConstraintOp.from_constraint(new.const)
)
for removed_name in sorted(set(conn_names).difference(metadata_names)):
conn_obj: Union[_ix_constraint_sig, _uq_constraint_sig] = conn_names[
removed_name
]
if not conn_obj.is_index and conn_obj.sig in unnamed_metadata_uniques:
continue
elif removed_name in doubled_constraints:
conn_uq, conn_idx = doubled_constraints[removed_name]
if (
conn_idx.sig not in metadata_indexes_by_sig
and conn_uq.sig not in metadata_uniques_by_sig
):
obj_removed(conn_uq)
obj_removed(conn_idx)
else:
obj_removed(conn_obj)
for existing_name in sorted(set(metadata_names).intersection(conn_names)):
metadata_obj = metadata_names[existing_name]
if existing_name in doubled_constraints:
conn_uq, conn_idx = doubled_constraints[existing_name]
if metadata_obj.is_index:
conn_obj = conn_idx
else:
conn_obj = conn_uq
else:
conn_obj = conn_names[existing_name]
if conn_obj.is_index != metadata_obj.is_index:
obj_removed(conn_obj)
obj_added(metadata_obj)
else:
msg = []
if conn_obj.is_unique != metadata_obj.is_unique:
msg.append(
" unique=%r to unique=%r"
% (conn_obj.is_unique, metadata_obj.is_unique)
)
if conn_obj.sig != metadata_obj.sig:
msg.append(
" expression %r to %r" % (conn_obj.sig, metadata_obj.sig)
)
if msg:
obj_changed(conn_obj, metadata_obj, msg)
for added_name in sorted(set(metadata_names).difference(conn_names)):
obj = metadata_names[added_name]
obj_added(obj)
for uq_sig in unnamed_metadata_uniques:
if uq_sig not in conn_uniques_by_sig:
obj_added(unnamed_metadata_uniques[uq_sig])
def _correct_for_uq_duplicates_uix(
conn_unique_constraints,
conn_indexes,
metadata_unique_constraints,
metadata_indexes,
dialect,
):
# dedupe unique indexes vs. constraints, since MySQL / Oracle
# doesn't really have unique constraints as a separate construct.
# but look in the metadata and try to maintain constructs
# that already seem to be defined one way or the other
# on that side. This logic was formerly local to MySQL dialect,
# generalized to Oracle and others. See #276
# resolve final rendered name for unique constraints defined in the
# metadata. this includes truncation of long names. naming convention
# names currently should already be set as cons.name, however leave this
# to the sqla_compat to decide.
metadata_cons_names = [
(sqla_compat._get_constraint_final_name(cons, dialect), cons)
for cons in metadata_unique_constraints
]
metadata_uq_names = {
name for name, cons in metadata_cons_names if name is not None
}
unnamed_metadata_uqs = {
_uq_constraint_sig(cons).sig
for name, cons in metadata_cons_names
if name is None
}
metadata_ix_names = {
sqla_compat._get_constraint_final_name(cons, dialect)
for cons in metadata_indexes
if cons.unique
}
# for reflection side, names are in their final database form
# already since they're from the database
conn_ix_names = {cons.name: cons for cons in conn_indexes if cons.unique}
uqs_dupe_indexes = {
cons.name: cons
for cons in conn_unique_constraints
if cons.info["duplicates_index"]
}
for overlap in uqs_dupe_indexes:
if overlap not in metadata_uq_names:
if (
_uq_constraint_sig(uqs_dupe_indexes[overlap]).sig
not in unnamed_metadata_uqs
):
conn_unique_constraints.discard(uqs_dupe_indexes[overlap])
elif overlap not in metadata_ix_names:
conn_indexes.discard(conn_ix_names[overlap])
@comparators.dispatch_for("column")
def _compare_nullable(
autogen_context: AutogenContext,
alter_column_op: AlterColumnOp,
schema: Optional[str],
tname: Union[quoted_name, str],
cname: Union[quoted_name, str],
conn_col: Column[Any],
metadata_col: Column[Any],
) -> None:
metadata_col_nullable = metadata_col.nullable
conn_col_nullable = conn_col.nullable
alter_column_op.existing_nullable = conn_col_nullable
if conn_col_nullable is not metadata_col_nullable:
if (
sqla_compat._server_default_is_computed(
metadata_col.server_default, conn_col.server_default
)
and sqla_compat._nullability_might_be_unset(metadata_col)
or (
sqla_compat._server_default_is_identity(
metadata_col.server_default, conn_col.server_default
)
)
):
log.info(
"Ignoring nullable change on identity column '%s.%s'",
tname,
cname,
)
else:
alter_column_op.modify_nullable = metadata_col_nullable
log.info(
"Detected %s on column '%s.%s'",
"NULL" if metadata_col_nullable else "NOT NULL",
tname,
cname,
)
@comparators.dispatch_for("column")
def _setup_autoincrement(
autogen_context: AutogenContext,
alter_column_op: AlterColumnOp,
schema: Optional[str],
tname: Union[quoted_name, str],
cname: quoted_name,
conn_col: Column[Any],
metadata_col: Column[Any],
) -> None:
if metadata_col.table._autoincrement_column is metadata_col:
alter_column_op.kw["autoincrement"] = True
elif metadata_col.autoincrement is True:
alter_column_op.kw["autoincrement"] = True
elif metadata_col.autoincrement is False:
alter_column_op.kw["autoincrement"] = False
@comparators.dispatch_for("column")
def _compare_type(
autogen_context: AutogenContext,
alter_column_op: AlterColumnOp,
schema: Optional[str],
tname: Union[quoted_name, str],
cname: Union[quoted_name, str],
conn_col: Column[Any],
metadata_col: Column[Any],
) -> None:
conn_type = conn_col.type
alter_column_op.existing_type = conn_type
metadata_type = metadata_col.type
if conn_type._type_affinity is sqltypes.NullType:
log.info(
"Couldn't determine database type " "for column '%s.%s'",
tname,
cname,
)
return
if metadata_type._type_affinity is sqltypes.NullType:
log.info(
"Column '%s.%s' has no type within " "the model; can't compare",
tname,
cname,
)
return
isdiff = autogen_context.migration_context._compare_type(
conn_col, metadata_col
)
if isdiff:
alter_column_op.modify_type = metadata_type
log.info(
"Detected type change from %r to %r on '%s.%s'",
conn_type,
metadata_type,
tname,
cname,
)
def _render_server_default_for_compare(
metadata_default: Optional[Any], autogen_context: AutogenContext
) -> Optional[str]:
if isinstance(metadata_default, sa_schema.DefaultClause):
if isinstance(metadata_default.arg, str):
metadata_default = metadata_default.arg
else:
metadata_default = str(
metadata_default.arg.compile(
dialect=autogen_context.dialect,
compile_kwargs={"literal_binds": True},
)
)
if isinstance(metadata_default, str):
return metadata_default
else:
return None
def _normalize_computed_default(sqltext: str) -> str:
"""we want to warn if a computed sql expression has changed. however
we don't want false positives and the warning is not that critical.
so filter out most forms of variability from the SQL text.
"""
return re.sub(r"[ \(\)'\"`\[\]]", "", sqltext).lower()
def _compare_computed_default(
autogen_context: AutogenContext,
alter_column_op: AlterColumnOp,
schema: Optional[str],
tname: str,
cname: str,
conn_col: Column[Any],
metadata_col: Column[Any],
) -> None:
rendered_metadata_default = str(
cast(sa_schema.Computed, metadata_col.server_default).sqltext.compile(
dialect=autogen_context.dialect,
compile_kwargs={"literal_binds": True},
)
)
# since we cannot change computed columns, we do only a crude comparison
# here where we try to eliminate syntactical differences in order to
# get a minimal comparison just to emit a warning.
rendered_metadata_default = _normalize_computed_default(
rendered_metadata_default
)
if isinstance(conn_col.server_default, sa_schema.Computed):
rendered_conn_default = str(
conn_col.server_default.sqltext.compile(
dialect=autogen_context.dialect,
compile_kwargs={"literal_binds": True},
)
)
if rendered_conn_default is None:
rendered_conn_default = ""
else:
rendered_conn_default = _normalize_computed_default(
rendered_conn_default
)
else:
rendered_conn_default = ""
if rendered_metadata_default != rendered_conn_default:
_warn_computed_not_supported(tname, cname)
def _warn_computed_not_supported(tname: str, cname: str) -> None:
util.warn("Computed default on %s.%s cannot be modified" % (tname, cname))
def _compare_identity_default(
autogen_context,
alter_column_op,
schema,
tname,
cname,
conn_col,
metadata_col,
):
impl = autogen_context.migration_context.impl
diff, ignored_attr, is_alter = impl._compare_identity_default(
metadata_col.server_default, conn_col.server_default
)
return diff, is_alter
@comparators.dispatch_for("column")
def _compare_server_default(
autogen_context: AutogenContext,
alter_column_op: AlterColumnOp,
schema: Optional[str],
tname: Union[quoted_name, str],
cname: Union[quoted_name, str],
conn_col: Column[Any],
metadata_col: Column[Any],
) -> Optional[bool]:
metadata_default = metadata_col.server_default
conn_col_default = conn_col.server_default
if conn_col_default is None and metadata_default is None:
return False
if sqla_compat._server_default_is_computed(metadata_default):
# return False in case of a computed column as the server
# default. Note that DDL for adding or removing "GENERATED AS" from
# an existing column is not currently known for any backend.
# Once SQLAlchemy can reflect "GENERATED" as the "computed" element,
# we would also want to ignore and/or warn for changes vs. the
# metadata (or support backend specific DDL if applicable).
if not sqla_compat.has_computed_reflection:
return False
else:
return (
_compare_computed_default( # type:ignore[func-returns-value]
autogen_context,
alter_column_op,
schema,
tname,
cname,
conn_col,
metadata_col,
)
)
if sqla_compat._server_default_is_computed(conn_col_default):
_warn_computed_not_supported(tname, cname)
return False
if sqla_compat._server_default_is_identity(
metadata_default, conn_col_default
):
alter_column_op.existing_server_default = conn_col_default
diff, is_alter = _compare_identity_default(
autogen_context,
alter_column_op,
schema,
tname,
cname,
conn_col,
metadata_col,
)
if is_alter:
alter_column_op.modify_server_default = metadata_default
if diff:
log.info(
"Detected server default on column '%s.%s': "
"identity options attributes %s",
tname,
cname,
sorted(diff),
)
else:
rendered_metadata_default = _render_server_default_for_compare(
metadata_default, autogen_context
)
rendered_conn_default = (
cast(Any, conn_col_default).arg.text if conn_col_default else None
)
alter_column_op.existing_server_default = conn_col_default
is_diff = autogen_context.migration_context._compare_server_default(
conn_col,
metadata_col,
rendered_metadata_default,
rendered_conn_default,
)
if is_diff:
alter_column_op.modify_server_default = metadata_default
log.info("Detected server default on column '%s.%s'", tname, cname)
return None
@comparators.dispatch_for("column")
def _compare_column_comment(
autogen_context: AutogenContext,
alter_column_op: AlterColumnOp,
schema: Optional[str],
tname: Union[quoted_name, str],
cname: quoted_name,
conn_col: Column[Any],
metadata_col: Column[Any],
) -> Optional[Literal[False]]:
assert autogen_context.dialect is not None
if not autogen_context.dialect.supports_comments:
return None
metadata_comment = metadata_col.comment
conn_col_comment = conn_col.comment
if conn_col_comment is None and metadata_comment is None:
return False
alter_column_op.existing_comment = conn_col_comment
if conn_col_comment != metadata_comment:
alter_column_op.modify_comment = metadata_comment
log.info("Detected column comment '%s.%s'", tname, cname)
return None
@comparators.dispatch_for("table")
def _compare_foreign_keys(
autogen_context: AutogenContext,
modify_table_ops: ModifyTableOps,
schema: Optional[str],
tname: Union[quoted_name, str],
conn_table: Optional[Table],
metadata_table: Optional[Table],
) -> None:
# if we're doing CREATE TABLE, all FKs are created
# inline within the table def
if conn_table is None or metadata_table is None:
return
inspector = autogen_context.inspector
metadata_fks = {
fk
for fk in metadata_table.constraints
if isinstance(fk, sa_schema.ForeignKeyConstraint)
}
conn_fks_list = [
fk
for fk in inspector.get_foreign_keys(tname, schema=schema)
if autogen_context.run_name_filters(
fk["name"],
"foreign_key_constraint",
{"table_name": tname, "schema_name": schema},
)
]
backend_reflects_fk_options = bool(
conn_fks_list and "options" in conn_fks_list[0]
)
conn_fks = {
_make_foreign_key(const, conn_table) # type: ignore[arg-type]
for const in conn_fks_list
}
# give the dialect a chance to correct the FKs to match more
# closely
autogen_context.migration_context.impl.correct_for_autogen_foreignkeys(
conn_fks, metadata_fks
)
metadata_fks_sig = {
_fk_constraint_sig(fk, include_options=backend_reflects_fk_options)
for fk in metadata_fks
}
conn_fks_sig = {
_fk_constraint_sig(fk, include_options=backend_reflects_fk_options)
for fk in conn_fks
}
conn_fks_by_sig = {c.sig: c for c in conn_fks_sig}
metadata_fks_by_sig = {c.sig: c for c in metadata_fks_sig}
metadata_fks_by_name = {
c.name: c for c in metadata_fks_sig if c.name is not None
}
conn_fks_by_name = {c.name: c for c in conn_fks_sig if c.name is not None}
def _add_fk(obj, compare_to):
if autogen_context.run_object_filters(
obj.const, obj.name, "foreign_key_constraint", False, compare_to
):
modify_table_ops.ops.append(
ops.CreateForeignKeyOp.from_constraint(const.const)
)
log.info(
"Detected added foreign key (%s)(%s) on table %s%s",
", ".join(obj.source_columns),
", ".join(obj.target_columns),
"%s." % obj.source_schema if obj.source_schema else "",
obj.source_table,
)
def _remove_fk(obj, compare_to):
if autogen_context.run_object_filters(
obj.const, obj.name, "foreign_key_constraint", True, compare_to
):
modify_table_ops.ops.append(
ops.DropConstraintOp.from_constraint(obj.const)
)
log.info(
"Detected removed foreign key (%s)(%s) on table %s%s",
", ".join(obj.source_columns),
", ".join(obj.target_columns),
"%s." % obj.source_schema if obj.source_schema else "",
obj.source_table,
)
# so far it appears we don't need to do this by name at all.
# SQLite doesn't preserve constraint names anyway
for removed_sig in set(conn_fks_by_sig).difference(metadata_fks_by_sig):
const = conn_fks_by_sig[removed_sig]
if removed_sig not in metadata_fks_by_sig:
compare_to = (
metadata_fks_by_name[const.name].const
if const.name in metadata_fks_by_name
else None
)
_remove_fk(const, compare_to)
for added_sig in set(metadata_fks_by_sig).difference(conn_fks_by_sig):
const = metadata_fks_by_sig[added_sig]
if added_sig not in conn_fks_by_sig:
compare_to = (
conn_fks_by_name[const.name].const
if const.name in conn_fks_by_name
else None
)
_add_fk(const, compare_to)
@comparators.dispatch_for("table")
def _compare_table_comment(
autogen_context: AutogenContext,
modify_table_ops: ModifyTableOps,
schema: Optional[str],
tname: Union[quoted_name, str],
conn_table: Optional[Table],
metadata_table: Optional[Table],
) -> None:
assert autogen_context.dialect is not None
if not autogen_context.dialect.supports_comments:
return
# if we're doing CREATE TABLE, comments will be created inline
# with the create_table op.
if conn_table is None or metadata_table is None:
return
if conn_table.comment is None and metadata_table.comment is None:
return
if metadata_table.comment is None and conn_table.comment is not None:
modify_table_ops.ops.append(
ops.DropTableCommentOp(
tname, existing_comment=conn_table.comment, schema=schema
)
)
elif metadata_table.comment != conn_table.comment:
modify_table_ops.ops.append(
ops.CreateTableCommentOp(
tname,
metadata_table.comment,
existing_comment=conn_table.comment,
schema=schema,
)
)
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