Autoincrement multiple primary keys (#474)

* feat(added autoincrement to primary key columns)

* test(added test to show autoincrement behavior works)

* update(added new changelog)

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Update CHANGES.rst

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Alex Grönholm <alex.gronholm@nextday.fi>

Author: 3 people

CHANGES.rst

@@ -1,6 +1,11 @@
 Version history
 ===============
 
+**UNRELEASED**
+
+- Added autoincrement to primary key columns to prevent missing field errors.
+  (`#473 <https://github.com/agronholm/sqlacodegen/issues/473>`_; PR by @jtmonroe)
+
 **4.0.3**
 
 - Improved rendering of ``Identity`` server defaults by explicitly rendering

src/sqlacodegen/generators.py

@@ -471,6 +471,9 @@ def render_column(
             )
             or column.primary_key
         )
+        is_autoincrement = (
+            isinstance(column.autoincrement, bool) and column.autoincrement
+        )
         has_index = any(
             set(i.columns) == {column} and uses_default_name(i)
             for i in column.table.indexes
@@ -494,6 +497,8 @@ def render_column(
             kwargs["key"] = column.key
         if is_primary:
             kwargs["primary_key"] = True
+        if is_autoincrement and is_primary:
+            kwargs["autoincrement"] = True
         if not column.nullable and not column.primary_key:
             kwargs["nullable"] = False
         if column.nullable and is_part_of_composite_pk:

tests/test_generator_declarative.py

@@ -1497,6 +1497,32 @@ class SimpleItems(Base):
     )
 
 
+def test_composite_autoincrement_pk(generator: CodeGenerator) -> None:
+    Table(
+        "simple_autoincrement_items",
+        generator.metadata,
+        Column("id1", INTEGER, primary_key=True, autoincrement=True),
+        Column("id2", INTEGER, primary_key=True),
+    )
+    validate_code(
+        generator.generate(),
+        """\
+from sqlalchemy import Integer
+from sqlalchemy.orm import DeclarativeBase, Mapped, mapped_column
+
+class Base(DeclarativeBase):
+    pass
+
+
+class SimpleAutoincrementItems(Base):
+    __tablename__ = 'simple_autoincrement_items'
+
+    id1: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
+    id2: Mapped[int] = mapped_column(Integer, primary_key=True)
+        """,
+    )
+
+
 def test_joined_inheritance(generator: CodeGenerator) -> None:
     Table(
         "simple_sub_items",