main commit

venv/lib/python3.12/site-packages/alembic/ddl/base.py

@@ -1,6 +1,3 @@
-# mypy: allow-untyped-defs, allow-incomplete-defs, allow-untyped-calls
-# mypy: no-warn-return-any, allow-any-generics
-
 from __future__ import annotations
 
 import functools
@@ -25,8 +22,6 @@ from ..util.sqla_compat import _table_for_constraint  # noqa
 if TYPE_CHECKING:
     from typing import Any
 
-    from sqlalchemy import Computed
-    from sqlalchemy import Identity
     from sqlalchemy.sql.compiler import Compiled
     from sqlalchemy.sql.compiler import DDLCompiler
     from sqlalchemy.sql.elements import TextClause
@@ -35,11 +30,14 @@ if TYPE_CHECKING:
     from sqlalchemy.sql.type_api import TypeEngine
 
     from .impl import DefaultImpl
+    from ..util.sqla_compat import Computed
+    from ..util.sqla_compat import Identity
 
 _ServerDefault = Union["TextClause", "FetchedValue", "Function[Any]", str]
 
 
 class AlterTable(DDLElement):
+
     """Represent an ALTER TABLE statement.
 
     Only the string name and optional schema name of the table
@@ -154,24 +152,17 @@ class AddColumn(AlterTable):
         name: str,
         column: Column[Any],
         schema: Optional[Union[quoted_name, str]] = None,
-        if_not_exists: Optional[bool] = None,
     ) -> None:
         super().__init__(name, schema=schema)
         self.column = column
-        self.if_not_exists = if_not_exists
 
 
 class DropColumn(AlterTable):
     def __init__(
-        self,
-        name: str,
-        column: Column[Any],
-        schema: Optional[str] = None,
-        if_exists: Optional[bool] = None,
+        self, name: str, column: Column[Any], schema: Optional[str] = None
     ) -> None:
         super().__init__(name, schema=schema)
         self.column = column
-        self.if_exists = if_exists
 
 
 class ColumnComment(AlterColumn):
@@ -196,9 +187,7 @@ def visit_rename_table(
 def visit_add_column(element: AddColumn, compiler: DDLCompiler, **kw) -> str:
     return "%s %s" % (
         alter_table(compiler, element.table_name, element.schema),
-        add_column(
-            compiler, element.column, if_not_exists=element.if_not_exists, **kw
-        ),
+        add_column(compiler, element.column, **kw),
     )
 
 
@@ -206,9 +195,7 @@ def visit_add_column(element: AddColumn, compiler: DDLCompiler, **kw) -> str:
 def visit_drop_column(element: DropColumn, compiler: DDLCompiler, **kw) -> str:
     return "%s %s" % (
         alter_table(compiler, element.table_name, element.schema),
-        drop_column(
-            compiler, element.column.name, if_exists=element.if_exists, **kw
-        ),
+        drop_column(compiler, element.column.name, **kw),
     )
 
 
@@ -248,11 +235,9 @@ def visit_column_default(
     return "%s %s %s" % (
         alter_table(compiler, element.table_name, element.schema),
         alter_column(compiler, element.column_name),
-        (
-            "SET DEFAULT %s" % format_server_default(compiler, element.default)
-            if element.default is not None
-            else "DROP DEFAULT"
-        ),
+        "SET DEFAULT %s" % format_server_default(compiler, element.default)
+        if element.default is not None
+        else "DROP DEFAULT",
     )
 
 
@@ -310,13 +295,9 @@ def format_server_default(
     compiler: DDLCompiler,
     default: Optional[_ServerDefault],
 ) -> str:
-    # this can be updated to use compiler.render_default_string
-    # for SQLAlchemy 2.0 and above; not in 1.4
-    default_str = compiler.get_column_default_string(
+    return compiler.get_column_default_string(
         Column("x", Integer, server_default=default)
     )
-    assert default_str is not None
-    return default_str
 
 
 def format_type(compiler: DDLCompiler, type_: TypeEngine) -> str:
@@ -331,29 +312,16 @@ def alter_table(
     return "ALTER TABLE %s" % format_table_name(compiler, name, schema)
 
 
-def drop_column(
-    compiler: DDLCompiler, name: str, if_exists: Optional[bool] = None, **kw
-) -> str:
-    return "DROP COLUMN %s%s" % (
-        "IF EXISTS " if if_exists else "",
-        format_column_name(compiler, name),
-    )
+def drop_column(compiler: DDLCompiler, name: str, **kw) -> str:
+    return "DROP COLUMN %s" % format_column_name(compiler, name)
 
 
 def alter_column(compiler: DDLCompiler, name: str) -> str:
     return "ALTER COLUMN %s" % format_column_name(compiler, name)
 
 
-def add_column(
-    compiler: DDLCompiler,
-    column: Column[Any],
-    if_not_exists: Optional[bool] = None,
-    **kw,
-) -> str:
-    text = "ADD COLUMN %s%s" % (
-        "IF NOT EXISTS " if if_not_exists else "",
-        compiler.get_column_specification(column, **kw),
-    )
+def add_column(compiler: DDLCompiler, column: Column[Any], **kw) -> str:
+    text = "ADD COLUMN %s" % compiler.get_column_specification(column, **kw)
 
     const = " ".join(
         compiler.process(constraint) for constraint in column.constraints