fix parseDriver function to return a correct Driver when using MySQL

internal/codegen/golang/driver.go

@@ -1,5 +1,7 @@
 package golang
 
+import "github.com/sqlc-dev/sqlc/internal/config"
+
 type SQLDriver string
 
 const (
@@ -15,12 +17,24 @@ const (
 	SQLDriverGoSQLDriverMySQL           = "github.com/go-sql-driver/mysql"
 )
 
-func parseDriver(sqlPackage string) SQLDriver {
+func parseDriver(sqlPackage string, engine string) SQLDriver {
 	switch sqlPackage {
 	case SQLPackagePGXV4:
 		return SQLDriverPGXV4
 	case SQLPackagePGXV5:
 		return SQLDriverPGXV5
+	default:
+		driver := driverFromEngine(engine)
+		return driver
+	}
+}
+
+func driverFromEngine(engine string) SQLDriver {
+	switch engine {
+	case string(config.EnginePostgreSQL):
+		return SQLDriverLibPQ
+	case string(config.EngineMySQL):
+		return SQLDriverGoSQLDriverMySQL
 	default:
 		return SQLDriverLibPQ
 	}

internal/codegen/golang/gen.go

@@ -123,7 +123,6 @@ func generate(req *plugin.CodeGenRequest, enums []Enum, structs []Struct, querie
 		Enums:    enums,
 		Structs:  structs,
 	}
-
 	golang := req.Settings.Go
 	tctx := tmplCtx{
 		EmitInterface:             golang.EmitInterface,
@@ -137,23 +136,22 @@ func generate(req *plugin.CodeGenRequest, enums []Enum, structs []Struct, querie
 		EmitAllEnumValues:         golang.EmitAllEnumValues,
 		UsesCopyFrom:              usesCopyFrom(queries),
 		UsesBatch:                 usesBatch(queries),
-		SQLDriver:                 parseDriver(golang.SqlPackage),
+		SQLDriver:                 parseDriver(golang.SqlPackage, req.Settings.Engine),
 		Q:                         "`",
 		Package:                   golang.Package,
 		Enums:                     enums,
 		Structs:                   structs,
 		SqlcVersion:               req.SqlcVersion,
 	}
 
-	if tctx.UsesCopyFrom && !tctx.SQLDriver.IsPGX() && golang.SqlDriver != SQLDriverGoSQLDriverMySQL {
+	if tctx.UsesCopyFrom && !tctx.SQLDriver.IsPGX() && tctx.SQLDriver != SQLDriverGoSQLDriverMySQL {
 		return nil, errors.New(":copyfrom is only supported by pgx and github.com/go-sql-driver/mysql")
 	}
 
-	if tctx.UsesCopyFrom && golang.SqlDriver == SQLDriverGoSQLDriverMySQL {
+	if tctx.UsesCopyFrom && tctx.SQLDriver == SQLDriverGoSQLDriverMySQL {
 		if err := checkNoTimesForMySQLCopyFrom(queries); err != nil {
 			return nil, err
 		}
-		tctx.SQLDriver = SQLDriverGoSQLDriverMySQL
 	}
 
 	if tctx.UsesBatch && !tctx.SQLDriver.IsPGX() {

internal/codegen/golang/imports.go

@@ -116,7 +116,7 @@ func (i *importer) dbImports() fileImports {
 		{Path: "context"},
 	}
 
-	sqlpkg := parseDriver(i.Settings.Go.SqlPackage)
+	sqlpkg := parseDriver(i.Settings.Go.SqlPackage, i.Settings.Engine)
 	switch sqlpkg {
 	case SQLDriverPGXV4:
 		pkg = append(pkg, ImportSpec{Path: "github.com/jackc/pgconn"})
@@ -160,7 +160,7 @@ func buildImports(settings *plugin.Settings, queries []Query, uses func(string)
 		std["database/sql"] = struct{}{}
 	}
 
-	sqlpkg := parseDriver(settings.Go.SqlPackage)
+	sqlpkg := parseDriver(settings.Go.SqlPackage, settings.Engine)
 	for _, q := range queries {
 		if q.Cmd == metadata.CmdExecResult {
 			switch sqlpkg {
@@ -374,7 +374,7 @@ func (i *importer) queryImports(filename string) fileImports {
 		std["context"] = struct{}{}
 	}
 
-	sqlpkg := parseDriver(i.Settings.Go.SqlPackage)
+	sqlpkg := parseDriver(i.Settings.Go.SqlPackage, i.Settings.Engine)
 	if sqlcSliceScan() {
 		std["strings"] = struct{}{}
 	}
@@ -459,7 +459,7 @@ func (i *importer) batchImports() fileImports {
 
 	std["context"] = struct{}{}
 	std["errors"] = struct{}{}
-	sqlpkg := parseDriver(i.Settings.Go.SqlPackage)
+	sqlpkg := parseDriver(i.Settings.Go.SqlPackage, i.Settings.Engine)
 	switch sqlpkg {
 	case SQLDriverPGXV4:
 		pkg[ImportSpec{Path: "github.com/jackc/pgx/v4"}] = struct{}{}

internal/codegen/golang/postgresql_type.go

@@ -36,7 +36,7 @@ func parseIdentifierString(name string) (*plugin.Identifier, error) {
 func postgresType(req *plugin.CodeGenRequest, col *plugin.Column) string {
 	columnType := sdk.DataType(col.Type)
 	notNull := col.NotNull || col.IsArray
-	driver := parseDriver(req.Settings.Go.SqlPackage)
+	driver := parseDriver(req.Settings.Go.SqlPackage, req.Settings.Engine)
 	emitPointersForNull := driver.IsPGX() && req.Settings.Go.EmitPointersForNullTypes
 
 	switch columnType {

internal/codegen/golang/result.go

@@ -208,7 +208,7 @@ func buildQueries(req *plugin.CodeGenRequest, structs []Struct) ([]Query, error)
 			Comments:     query.Comments,
 			Table:        query.InsertIntoTable,
 		}
-		sqlpkg := parseDriver(req.Settings.Go.SqlPackage)
+		sqlpkg := parseDriver(req.Settings.Go.SqlPackage, req.Settings.Engine)
 
 		qpl := int(*req.Settings.Go.QueryParameterLimit)