DSN: Align ParseDriver and detectDriver alias sets #5588

pkg/dsn/driver.go

@@ -19,17 +19,14 @@ const (
 )
 
 // ParseDriver canonicalizes a user-supplied driver identifier to one of the
-// DriverMySQL/DriverPostgres/DriverSQLite3/DriverTiDB constants. Comparison is
-// case-insensitive and tolerates surrounding whitespace. "mariadb" collapses
-// to DriverMySQL because both share the same wire protocol and GORM dialect.
-// The aliases "sqlite", "test", "file" and the empty string normalize to
-// DriverSQLite3. Unrecognized inputs return an empty string so callers can
-// distinguish them from supported drivers in a switch.
+// DriverMySQL/DriverPostgres/DriverSQLite3/DriverTiDB constants (case- and
+// whitespace-insensitive). Aliases: "mariadb" → MySQL (shared GORM dialect),
+// "postgresql" → Postgres, "sqlite"/"test"/"file"/"" → SQLite3; unknown → "".
 func ParseDriver(s string) string {
 	switch strings.ToLower(strings.TrimSpace(s)) {
 	case DriverMySQL, DriverMariaDB:
 		return DriverMySQL
-	case DriverPostgres:
+	case DriverPostgres, "postgresql":
 		return DriverPostgres
 	case DriverSQLite3, "sqlite", "test", "file", "":
 		return DriverSQLite3

pkg/dsn/driver_test.go

@@ -20,6 +20,9 @@ func TestParseDriver(t *testing.T) {
 	})
 	t.Run("Postgres", func(t *testing.T) {
 		assert.Equal(t, DriverPostgres, ParseDriver("postgres"))
+		// URI-style DSNs spell the driver "postgresql"; accept it as a Postgres alias.
+		assert.Equal(t, DriverPostgres, ParseDriver("postgresql"))
+		assert.Equal(t, DriverPostgres, ParseDriver("PostgreSQL"))
 	})
 	t.Run("SQLite3", func(t *testing.T) {
 		assert.Equal(t, DriverSQLite3, ParseDriver("sqlite3"))
@@ -44,7 +47,6 @@ func TestParseDriver(t *testing.T) {
 	t.Run("Unknown", func(t *testing.T) {
 		// Unknown inputs return an empty string so the caller's `default` arm fires.
 		assert.Equal(t, "", ParseDriver("oracle"))
-		assert.Equal(t, "", ParseDriver("postgresql"))
 		assert.Equal(t, "", ParseDriver("garbage"))
 	})
 }

pkg/dsn/dsn.go

@@ -365,24 +365,17 @@ func (d *DSN) splitKeyValue(input string) ([]string, bool) {
 	return tokens, true
 }
 
-// detectDriver infers the driver name from DSN contents when it is not explicitly specified.
+// detectDriver infers the driver name from DSN contents. Explicit driver names
+// flow through ParseDriver so both helpers share an alias set; unknown but
+// non-empty names are kept (lowercased) rather than misclassified by the
+// DSN-string heuristics below.
 func (d *DSN) detectDriver() {
-	driver := strings.ToLower(d.Driver)
-
-	switch driver {
-	case "postgres", "postgresql":
-		d.Driver = DriverPostgres
-		return
-	case "mysql", "mariadb":
-		d.Driver = DriverMySQL
-		return
-	case "sqlite", "sqlite3", "file":
-		d.Driver = DriverSQLite3
-		return
-	}
-
-	if driver != "" {
-		d.Driver = driver
+	if d.Driver != "" {
+		if normalized := ParseDriver(d.Driver); normalized != "" {
+			d.Driver = normalized
+			return
+		}
+		d.Driver = strings.ToLower(d.Driver)
 		return
 	}
 

pkg/dsn/parse_test.go

@@ -105,3 +105,33 @@ func TestParse(t *testing.T) {
 		})
 	}
 }
+
+// TestParse_DriverDetection exercises detectDriver via Parse: alias unification
+// with ParseDriver and the preserve-unknown contract.
+func TestParse_DriverDetection(t *testing.T) {
+	t.Run("PostgresqlAliasNormalizes", func(t *testing.T) {
+		got := Parse("postgresql://alice:s3cr3t@db.local:5432/app")
+		assert.Equal(t, DriverPostgres, got.Driver)
+	})
+	t.Run("PostgresqlAliasCaseInsensitive", func(t *testing.T) {
+		got := Parse("POSTGRESQL://alice:s3cr3t@db.local:5432/app")
+		assert.Equal(t, DriverPostgres, got.Driver)
+	})
+	t.Run("MariaDBAliasCollapsesToMySQL", func(t *testing.T) {
+		got := Parse("mariadb://user:secret@db.local:3306/app")
+		assert.Equal(t, DriverMySQL, got.Driver)
+	})
+	t.Run("SqliteAliasNormalizes", func(t *testing.T) {
+		got := Parse("sqlite:///data/index.db")
+		assert.Equal(t, DriverSQLite3, got.Driver)
+	})
+	t.Run("UnknownDriverPreserved", func(t *testing.T) {
+		// Unknown explicit drivers are kept instead of falling through to heuristics.
+		got := Parse("oracle://user:secret@db.local:1521/app")
+		assert.Equal(t, "oracle", got.Driver)
+	})
+	t.Run("UnknownDriverPreservedLowercased", func(t *testing.T) {
+		got := Parse("Snowflake://user:secret@account.region/db")
+		assert.Equal(t, "snowflake", got.Driver)
+	})
+}