fix: migration 0029 idempotent (IF NOT EXISTS für Enum + Tabelle)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/migrations/versions/0029_special_assignments.py

@@ -12,9 +12,7 @@ Neue Tabelle special_assignments:
   - label / description (optional)
   - Overlap-Check per Constraint (date_from <= date_to) + App-seitige Prüfung
 """
-import sqlalchemy as sa
 from alembic import op
-from sqlalchemy.dialects import postgresql
 
 revision = "0029"
 down_revision = "0028"
@@ -25,37 +23,46 @@ depends_on = None
 def upgrade() -> None:
     op.execute("CREATE EXTENSION IF NOT EXISTS btree_gist")
 
-    # Enum erzeugen
+    # Enum erzeugen (IF NOT EXISTS: falls create_all in lifespan den Typ schon angelegt hat)
-    op.execute("CREATE TYPE assignment_mode AS ENUM ('fza', 'payroll', 'both')")
+    op.execute("CREATE TYPE IF NOT EXISTS assignment_mode AS ENUM ('fza', 'payroll', 'both')")
 
-    op.create_table(
+    # Tabelle nur anlegen falls noch nicht vorhanden (idempotent)
-        "special_assignments",
+    op.execute("""
-        sa.Column("id", postgresql.UUID(as_uuid=True), primary_key=True, server_default=sa.text("gen_random_uuid()")),
+        CREATE TABLE IF NOT EXISTS special_assignments (
-        sa.Column("user_id", postgresql.UUID(as_uuid=True), sa.ForeignKey("users.id", ondelete="CASCADE"), nullable=False, index=True),
+            id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
-        sa.Column("company_id", postgresql.UUID(as_uuid=True), sa.ForeignKey("companies.id", ondelete="CASCADE"), nullable=False, index=True),
+            user_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
-        sa.Column("date_from", sa.Date, nullable=False),
+            company_id UUID NOT NULL REFERENCES companies(id) ON DELETE CASCADE,
-        sa.Column("date_to", sa.Date, nullable=False),
+            date_from DATE NOT NULL,
-        sa.Column("factor", sa.Numeric(5, 3), nullable=False),
+            date_to DATE NOT NULL,
-        sa.Column("mode", sa.Enum("fza", "payroll", "both", name="assignment_mode", create_type=False), nullable=False, server_default="both"),
+            factor NUMERIC(5,3) NOT NULL,
-        sa.Column("label", sa.String(100), nullable=True),
+            mode assignment_mode NOT NULL DEFAULT 'both',
-        sa.Column("description", sa.Text, nullable=True),
+            label VARCHAR(100),
-        sa.CheckConstraint("factor > 0 AND factor <= 10", name="ck_special_assignment_factor"),
+            description TEXT,
-        sa.CheckConstraint("date_from <= date_to", name="ck_special_assignment_dates"),
+            CONSTRAINT ck_special_assignment_factor CHECK (factor > 0 AND factor <= 10),
-    )
+            CONSTRAINT ck_special_assignment_dates CHECK (date_from <= date_to)
-
-    # Exclusion Constraint: kein überlappender Zeitraum pro User
-    op.execute(
-        """
-        ALTER TABLE special_assignments
-        ADD CONSTRAINT special_assignments_no_overlap
-        EXCLUDE USING gist (
-            user_id WITH =,
-            daterange(date_from, date_to, '[]') WITH &&
         )
-        """
+    """)
-    )
+    op.execute("CREATE INDEX IF NOT EXISTS ix_special_assignments_user_id ON special_assignments(user_id)")
+    op.execute("CREATE INDEX IF NOT EXISTS ix_special_assignments_company_id ON special_assignments(company_id)")
+
+    # Exclusion Constraint (nur falls noch nicht vorhanden)
+    op.execute("""
+        DO $$
+        BEGIN
+            IF NOT EXISTS (
+                SELECT 1 FROM pg_constraint WHERE conname = 'special_assignments_no_overlap'
+            ) THEN
+                ALTER TABLE special_assignments
+                ADD CONSTRAINT special_assignments_no_overlap
+                EXCLUDE USING gist (
+                    user_id WITH =,
+                    daterange(date_from, date_to, '[]') WITH &&
+                );
+            END IF;
+        END $$
+    """)
 
 
 def downgrade() -> None:
-    op.drop_table("special_assignments")
+    op.execute("DROP TABLE IF EXISTS special_assignments")
     op.execute("DROP TYPE IF EXISTS assignment_mode")