Validate check name is unique (#429)

Validate that check name is unique before starting the migration.

Author: ryanslade

pkg/migrations/op_set_check.go

@@ -8,6 +8,7 @@ import (
 	"strings"
 
 	"github.com/lib/pq"
+
 	"github.com/xataio/pgroll/pkg/db"
 	"github.com/xataio/pgroll/pkg/schema"
 )
@@ -58,6 +59,18 @@ func (o *OpSetCheckConstraint) Validate(ctx context.Context, s *schema.Schema) e
 		}
 	}
 
+	table := s.GetTable(o.Table)
+	if table == nil {
+		return TableDoesNotExistError{Name: o.Table}
+	}
+
+	if table.ConstraintExists(o.Check.Name) {
+		return ConstraintAlreadyExistsError{
+			Table:      table.Name,
+			Constraint: o.Check.Name,
+		}
+	}
+
 	if o.Up == "" {
 		return FieldRequiredError{Name: "up"}
 	}

pkg/migrations/op_set_check_test.go

@@ -6,9 +6,9 @@ import (
 	"database/sql"
 	"testing"
 
-	"github.com/xataio/pgroll/internal/testutils"
-
 	"github.com/stretchr/testify/assert"
+
+	"github.com/xataio/pgroll/internal/testutils"
 	"github.com/xataio/pgroll/pkg/migrations"
 )
 
@@ -543,6 +543,67 @@ func TestSetCheckConstraint(t *testing.T) {
 				ColumnMustHaveComment(t, db, schema, "posts", "title", "the title of the post")
 			},
 		},
+		{
+			name: "validate that check constraint name is unique",
+			migrations: []migrations.Migration{
+				{
+					Name: "01_add_table",
+					Operations: migrations.Operations{
+						&migrations.OpCreateTable{
+							Name: "posts",
+							Columns: []migrations.Column{
+								{
+									Name: "id",
+									Type: "serial",
+									Pk:   ptr(true),
+								},
+								{
+									Name: "title",
+									Type: "text",
+								},
+							},
+						},
+					},
+				},
+				{
+					Name: "02_add_check_constraint",
+					Operations: migrations.Operations{
+						&migrations.OpAlterColumn{
+							Table:  "posts",
+							Column: "title",
+							Check: &migrations.CheckConstraint{
+								Name:       "check_title_length",
+								Constraint: "length(title) > 3",
+							},
+							Up:   "(SELECT CASE WHEN length(title) <= 3 THEN LPAD(title, 4, '-') ELSE title END)",
+							Down: "title",
+						},
+					},
+				},
+				{
+					Name: "03_add_check_constraint_again",
+					Operations: migrations.Operations{
+						&migrations.OpAlterColumn{
+							Table:  "posts",
+							Column: "title",
+							Check: &migrations.CheckConstraint{
+								Name:       "check_title_length",
+								Constraint: "length(title) > 3",
+							},
+							Up:   "(SELECT CASE WHEN length(title) <= 3 THEN LPAD(title, 4, '-') ELSE title END)",
+							Down: "title",
+						},
+					},
+				},
+			},
+			wantStartErr: migrations.ConstraintAlreadyExistsError{
+				Table:      "posts",
+				Constraint: "check_title_length",
+			},
+			afterStart:    func(t *testing.T, db *sql.DB, schema string) {},
+			afterRollback: func(t *testing.T, db *sql.DB, schema string) {},
+			afterComplete: func(t *testing.T, db *sql.DB, schema string) {},
+		},
 	})
 }
 

pkg/state/state.go

@@ -542,13 +542,13 @@ func (s *State) Start(ctx context.Context, schemaname string, migration *migrati
 		return nil, err
 	}
 
-	var schema schema.Schema
-	err = json.Unmarshal([]byte(rawSchema), &schema)
+	var unmarshalledSchema schema.Schema
+	err = json.Unmarshal([]byte(rawSchema), &unmarshalledSchema)
 	if err != nil {
 		return nil, fmt.Errorf("unable to unmarshal schema: %w", err)
 	}
 
-	return &schema, nil
+	return &unmarshalledSchema, nil
 }
 
 // Complete marks a migration as completed