fix: adapt CockroachDB DDL for Postgres in migration runner (#2089)

* fix: adapt CockroachDB DDL for Postgres in production migration runner

The migration runner executes SQL files as-is, but migrations are written
for CockroachDB (DROP INDEX CASCADE for unique constraints). When running
against Postgres (demo, local dev), this fails because Postgres requires
ALTER TABLE DROP CONSTRAINT.

Add adaptCockroachDDLForPostgres to the runner (mirroring the existing
test adapter in shared/platform/testdb) so demo deployments work.

* test: add multi-statement migration test for DDL adapter

* fix: port ADD CONSTRAINT CHECK adapter from testdb to production runner

Bring the production migration adapter to parity with the testdb
adapter by adding the regex-based ADD CONSTRAINT CHECK rewrite for
public-schema tables.

---------

Co-authored-by: Ben Coombs <bjcoombs@users.noreply.github.com>

Author: bjcoombs

internal/migrations/adapt_test.go

@@ -0,0 +1,60 @@
+package migrations
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestAdaptCockroachDDLForPostgres_NoChanges(t *testing.T) {
+	input := `CREATE TABLE foo (id UUID PRIMARY KEY);`
+	assert.Equal(t, input, adaptCockroachDDLForPostgres(input))
+}
+
+func TestAdaptCockroachDDLForPostgres_ManifestVersionUniqueConstraint(t *testing.T) {
+	input := `DROP INDEX IF EXISTS uq_manifest_version_version CASCADE;`
+	result := adaptCockroachDDLForPostgres(input)
+	assert.Contains(t, result, "ALTER TABLE manifest_version DROP CONSTRAINT IF EXISTS uq_manifest_version_version")
+	assert.NotContains(t, result, "DROP INDEX")
+}
+
+func TestAdaptCockroachDDLForPostgres_SagaDefinitionUniqueConstraint(t *testing.T) {
+	input := `DROP INDEX IF EXISTS "public"."uq_platform_saga_definition_name" CASCADE;`
+	result := adaptCockroachDDLForPostgres(input)
+	assert.Contains(t, result, `ALTER TABLE "public"."platform_saga_definition" DROP CONSTRAINT IF EXISTS "uq_platform_saga_definition_name"`)
+	assert.NotContains(t, result, "DROP INDEX")
+}
+
+func TestAdaptCockroachDDLForPostgres_AddConstraintCheck(t *testing.T) {
+	input := `ALTER TABLE public.my_table ADD CONSTRAINT chk_status CHECK (status IN ('a','b'));`
+	result := adaptCockroachDDLForPostgres(input)
+	assert.Contains(t, result, "DO $compat$ BEGIN")
+	assert.Contains(t, result, "EXCEPTION WHEN duplicate_object THEN NULL")
+	assert.Contains(t, result, "ADD CONSTRAINT chk_status CHECK")
+}
+
+func TestAdaptCockroachDDLForPostgres_AddConstraintIfNotExists(t *testing.T) {
+	input := `ALTER TABLE public.my_table ADD CONSTRAINT IF NOT EXISTS chk_val CHECK (val > 0);`
+	result := adaptCockroachDDLForPostgres(input)
+	assert.Contains(t, result, "DO $compat$ BEGIN")
+	assert.NotContains(t, result, "IF NOT EXISTS")
+	assert.Contains(t, result, "ADD CONSTRAINT chk_val CHECK")
+}
+
+func TestAdaptCockroachDDLForPostgres_MultiStatementMigration(t *testing.T) {
+	input := `UPDATE manifest_version SET version_new = version::TEXT WHERE version_new IS NULL;
+ALTER TABLE manifest_version ALTER COLUMN version_new SET NOT NULL;
+DROP INDEX IF EXISTS uq_manifest_version_version CASCADE;
+DROP INDEX IF EXISTS idx_manifest_version_version;
+ALTER TABLE manifest_version DROP COLUMN version;`
+
+	result := adaptCockroachDDLForPostgres(input)
+
+	// The DROP INDEX CASCADE for the unique constraint should be rewritten
+	assert.Contains(t, result, "ALTER TABLE manifest_version DROP CONSTRAINT IF EXISTS uq_manifest_version_version")
+	// The regular DROP INDEX (non-unique) should be left unchanged
+	assert.Contains(t, result, "DROP INDEX IF EXISTS idx_manifest_version_version")
+	// Other statements should be untouched
+	assert.Contains(t, result, "UPDATE manifest_version SET version_new")
+	assert.Contains(t, result, "ALTER TABLE manifest_version DROP COLUMN version")
+}

internal/migrations/runner.go

@@ -17,6 +17,7 @@ import (
 	"log/slog"
 	"net/url"
 	"os"
+	"regexp"
 	"sort"
 	"strings"
 	"time"
@@ -400,7 +401,12 @@ func applyDatabaseMigrations(ctx context.Context, dsn, dbName string, migrations
 
 		logger.Info("applying migration", "database", dbName, "service", m.service, "file", m.filename)
 
-		if _, err := conn.Exec(ctx, m.sql); err != nil {
+		sql := m.sql
+		if driver == DriverPostgres {
+			sql = adaptCockroachDDLForPostgres(sql)
+		}
+
+		if _, err := conn.Exec(ctx, sql); err != nil {
 			return fmt.Errorf("execute %s/%s: %w", m.service, m.filename, err)
 		}
 
@@ -590,3 +596,36 @@ func runPostgresPreMigrationFixups(ctx context.Context, superuserDSN string, dri
 
 	return nil
 }
+
+// adaptCockroachDDLForPostgres rewrites CockroachDB-specific DDL to work on PostgreSQL.
+//
+// Migrations are written for CockroachDB (production). When running against
+// PostgreSQL (demo, local dev), this function translates known incompatibilities:
+//   - DROP INDEX CASCADE for unique constraints -> ALTER TABLE DROP CONSTRAINT
+//   - ADD CONSTRAINT [IF NOT EXISTS] CHECK on public-schema tables -> idempotent DO block
+//
+// This mirrors shared/platform/testdb/pgx.go:adaptCockroachDDLForPostgres.
+func adaptCockroachDDLForPostgres(sql string) string {
+	// CockroachDB uses DROP INDEX CASCADE for unique constraints;
+	// PostgreSQL requires ALTER TABLE DROP CONSTRAINT.
+	sql = strings.ReplaceAll(sql,
+		`DROP INDEX IF EXISTS "public"."uq_platform_saga_definition_name" CASCADE`,
+		`ALTER TABLE "public"."platform_saga_definition" DROP CONSTRAINT IF EXISTS "uq_platform_saga_definition_name"`,
+	)
+	sql = strings.ReplaceAll(sql,
+		`DROP INDEX IF EXISTS uq_manifest_version_version CASCADE`,
+		`ALTER TABLE manifest_version DROP CONSTRAINT IF EXISTS uq_manifest_version_version`,
+	)
+
+	// Wrap ADD CONSTRAINT ... CHECK statements targeting public-schema tables in a
+	// DO block that ignores duplicate_object errors. In multi-tenant tests, multiple
+	// schemas apply the same migration against the shared public schema.
+	re := regexp.MustCompile(`(?s)(ALTER TABLE\s+public\.\S+\s+)ADD CONSTRAINT(?:\s+IF NOT EXISTS)?\s+(\S+\s+CHECK\s*\([^;]+?\));`)
+	sql = re.ReplaceAllStringFunc(sql, func(match string) string {
+		inner := strings.Replace(match, "ADD CONSTRAINT IF NOT EXISTS", "ADD CONSTRAINT", 1)
+		inner = strings.TrimSuffix(strings.TrimSpace(inner), ";")
+		return "DO $compat$ BEGIN " + inner + "; EXCEPTION WHEN duplicate_object THEN NULL; END $compat$;"
+	})
+
+	return sql
+}