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EDIT :: compare.py

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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