fix: preserve MySQL schema fidelity

cmd/relspec/convert.go

@@ -181,12 +181,12 @@ Examples:
 }
 
 func init() {
-	convertCmd.Flags().StringVar(&convertSourceType, "from", "", "Source format (dbml, dctx, drawdb, graphql, json, yaml, gorm, bun, drizzle, prisma, typeorm, pgsql, sqlite)")
+	convertCmd.Flags().StringVar(&convertSourceType, "from", "", "Source format (dbml, dctx, drawdb, graphql, json, yaml, gorm, bun, drizzle, prisma, typeorm, pgsql, mssql, mysql, sqlite)")
 	convertCmd.Flags().StringVar(&convertSourcePath, "from-path", "", "Source file path (for file-based formats)")
-	convertCmd.Flags().StringVar(&convertSourceConn, "from-conn", "", "Source connection string (for pgsql) or file path (for sqlite)")
+	convertCmd.Flags().StringVar(&convertSourceConn, "from-conn", "", "Source connection string (pgsql, mssql, mysql) or file path (sqlite)")
 	convertCmd.Flags().StringSliceVar(&convertFromList, "from-list", nil, "Comma-separated list of source file paths to read and merge (mutually exclusive with --from-path)")
 
-	convertCmd.Flags().StringVar(&convertTargetType, "to", "", "Target format (dbml, dctx, drawdb, graphql, json, yaml, gorm, bun, drizzle, prisma, typeorm, pgsql)")
+	convertCmd.Flags().StringVar(&convertTargetType, "to", "", "Target format (dbml, dctx, drawdb, graphql, json, yaml, gorm, bun, drizzle, prisma, typeorm, pgsql, mssql, mysql, sqlite)")
 	convertCmd.Flags().StringVar(&convertTargetPath, "to-path", "", "Target output path (file or directory)")
 	convertCmd.Flags().StringVar(&convertPackageName, "package", "", "Package name (for code generation formats like gorm/bun)")
 	convertCmd.Flags().StringVar(&convertSchemaFilter, "schema", "", "Filter to a specific schema by name (required for formats like dctx that only support single schemas)")
@@ -449,7 +449,7 @@ func readDatabaseForConvert(dbType, filePath, connString string) (*models.Databa
 	return db, nil
 }
 
-func writeDatabase(db *models.Database, dbType, outputPath, packageName, schemaFilter string, flattenSchema bool, nullableTypes, nullableArrays string, continueOnError bool, extraFields string) error {
+func writeDatabase(db *models.Database, dbType, outputPath, packageName, schemaFilter string, flattenSchema bool, nullableTypes, nullableArrays string, continueOnError bool, extraFields string, strict ...bool) error {
 	if lowercaseIdentifiers {
 		var err error
 		schemaFilter = strings.ToLower(schemaFilter)
@@ -462,6 +462,9 @@ func writeDatabase(db *models.Database, dbType, outputPath, packageName, schemaF
 	var writer writers.Writer
 
 	writerOpts := newWriterOptions(outputPath, packageName, flattenSchema, nullableTypes, nullableArrays, continueOnError)
+	if len(strict) > 0 {
+		writerOpts.StrictConversion = writerOpts.StrictConversion || strict[0]
+	}
 	if extraFields != "" {
 		extraFieldsJSON, err := loadExtraFields(dbType, extraFields)
 		if err != nil {
@@ -611,6 +614,19 @@ func validateWriteTarget(db *models.Database, dbType, packageName, schemaFilter,
 		"pgsql", "postgres", "postgresql", "sql",
 		"mssql", "sqlserver", "mssql2016", "mssql2017", "mssql2019", "mssql2022",
 		"sqlite", "sqlite3", "prisma", "typeorm", "graphql", "gql":
+	case "mysql", "mariadb":
+		selected := db
+		if schemaFilter != "" {
+			selected = &models.Database{}
+			for _, s := range db.Schemas {
+				if s.Name == schemaFilter {
+					selected.Schemas = append(selected.Schemas, s)
+				}
+			}
+		}
+		if _, err := wmysql.NewWriter(newWriterOptions("", packageName, false, "", "", false)).Statements(selected); err != nil {
+			return err
+		}
 	case "gorm", "bun":
 		if packageName == "" {
 			return fmt.Errorf("package name is required for %s format (use --package flag)", dbType)

cmd/relspec/job.go

@@ -874,7 +874,7 @@ func writeJobOutput(rj *resolvedJob, db *models.Database, lg *jobLogger) error {
 	lg.logf("writing output: %s (%s)", rj.outputPath, format)
 
 	write := func(target string) error {
-		return writeDatabase(db, format, target, o.Package, o.Schema, o.FlattenSchema, o.Types, o.ArrayNullable, o.ContinueOnError, "")
+		return writeDatabase(db, format, target, o.Package, o.Schema, o.FlattenSchema, o.Types, o.ArrayNullable, o.ContinueOnError, "", o.StrictConversion)
 	}
 	// Single-file formats are written to a temp file and renamed into place so
 	// a failure never leaves a partial or truncated output. Directory-emitting

cmd/relspec/prisma_options.go

@@ -32,5 +32,6 @@ func newWriterOptions(outputPath, packageName string, flattenSchema bool, nullab
 		Prisma7:              prisma7,
 		ContinueOnError:      continueOnError,
 		StrictDirectives:     strictDirectives,
+		StrictConversion:     strictConversion,
 	}
 }

cmd/relspec/root.go

@@ -18,6 +18,7 @@ var (
 	noVersion            bool
 	silent               bool
 	strictDirectives     bool
+	strictConversion     bool
 	lowercaseIdentifiers bool
 	typeMapFlags         []string
 	typeMappings         map[string]string
@@ -62,6 +63,7 @@ func init() {
 	rootCmd.PersistentFlags().StringArrayVar(&typeMapFlags, "type-map", nil, "Override a SQL-to-Go type mapping for bun/gorm output as sqltype=gotype (repeatable), e.g. --type-map uuid=uuid.UUID --type-map numeric=decimal.Decimal")
 	rootCmd.PersistentFlags().BoolVar(&noVersion, "no-version", false, "Suppress the RelSpec version header")
 	rootCmd.PersistentFlags().BoolVar(&silent, "silent", false, "Suppress progress and status messages (errors are still shown)")
+	rootCmd.PersistentFlags().BoolVar(&strictConversion, "strict-conversion", false, "Reject known lossy MySQL schema conversions before writing or executing output")
 	rootCmd.PersistentFlags().BoolVar(&strictDirectives, "strict-directives", false, "Fail on unknown or untranslatable DBML dialect directives (@postgres:, @sqlite:, …)")
 }
 

cmd/relspec/strict_conversion_test.go

@@ -0,0 +1,41 @@
+package main
+
+import (
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/jobs"
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+)
+
+func TestStrictConversionOptionAndDryRun(t *testing.T) {
+	prior := strictConversion
+	strictConversion = true
+	t.Cleanup(func() { strictConversion = prior })
+	if flag := rootCmd.PersistentFlags().Lookup("strict-conversion"); flag == nil {
+		t.Fatal("missing --strict-conversion")
+	}
+	db := models.InitDatabase("shop")
+	s := models.InitSchema("shop")
+	table := models.InitTable("users", "shop")
+	col := models.InitColumn("value", "users", "shop")
+	col.Type = "unknown_type"
+	table.Columns[col.Name] = col
+	s.Tables = append(s.Tables, table)
+	db.Schemas = append(db.Schemas, s)
+	if err := validateWriteTarget(db, "mysql", "", "", ""); err == nil || !strings.Contains(err.Error(), "lossy MySQL") {
+		t.Fatalf("dry run bypassed strict validation: %v", err)
+	}
+	strictConversion = false
+	out := filepath.Join(t.TempDir(), "out.sql")
+	rj := &resolvedJob{job: &jobs.Job{Output: &jobs.Output{Format: "mysql"}, Options: jobs.Options{StrictConversion: true}}, outputPath: out}
+	if err := writeJobOutput(rj, db, &jobLogger{file: io.Discard}); err == nil || !strings.Contains(err.Error(), "lossy MySQL") {
+		t.Fatalf("job option bypassed strict validation: %v", err)
+	}
+	if _, err := os.Stat(out); !os.IsNotExist(err) {
+		t.Fatalf("strict job created output: %v", err)
+	}
+}