mysqltopo: use the block-mysql driver (#22)

* mysqltopo: use the block-mysql driver

strata links github.com/block/mysql — Block's fork of go-sql-driver/mysql —
for capabilities upstream does not carry. That fork is moving from a `replace`
directive to its own module path (block/mysql#3), because `replace` is not
inherited across module boundaries and so cannot reach consumers of a library.

Once the path differs, a binary linking both packages gets two distinct
`*mysql.MySQLError` types, and `errors.As` across that boundary silently
returns false. convertError here depends on exactly that assertion to map 1062
to NodeExists and 1213/1205 to Timeout, and strata's own test helpers assert on
the errors this package returns — so mysqltopo and strata must agree on which
package the type comes from.

Scope is deliberately mysqltopo only: it is Block-added, so editing it costs
nothing when merging upstream vitess. The remaining go-sql-driver imports live
in upstream-owned endtoend tests, which keep using upstream — the module stays
in go.mod and both can coexist.

The dependency is pinned to the block/mysql PR branch and must be re-pointed at
its master commit before this merges.

Verified: go/vt/topo/mysqltopo tests pass against MySQL 8.0.44.

* go mod tidy: block/mysql is a direct dependency now

* Pin block/mysql at merged master (block/mysql#3)

* mysqltopo: state the driver invariant this package actually holds

The import comment claimed one driver in the binary; eight end-to-end test
files still import go-sql-driver, so that is false. The local invariant is
both true and sufficient: every *sql.DB this package opens uses the driver
whose *mysql.MySQLError convertError asserts on.

Add a package const for the name and use it at all five sql.Open sites, so
that invariant is one grep rather than five, and fix the convertError comment
to credit block-mysql.

Author: morgo

go.mod

@@ -95,6 +95,7 @@ require (
 	github.com/aws/aws-sdk-go-v2/feature/s3/transfermanager v0.1.15
 	github.com/aws/aws-sdk-go-v2/service/s3 v1.99.0
 	github.com/aws/smithy-go v1.24.3
+	github.com/block/mysql v0.0.0-20260906201522-a3178f8dca69
 	github.com/bndr/gotabulate v1.1.2
 	github.com/brianvoe/gofakeit/v7 v7.14.1
 	github.com/dustin/go-humanize v1.0.1
@@ -121,7 +122,7 @@ require (
 )
 
 require (
-	filippo.io/edwards25519 v1.1.1 // indirect
+	filippo.io/edwards25519 v1.2.0 // indirect
 	github.com/DataDog/datadog-agent/comp/core/tagger/origindetection v0.77.3 // indirect
 	github.com/DataDog/datadog-agent/pkg/opentelemetry-mapping-go/otlp/attributes v0.77.3 // indirect
 	github.com/DataDog/datadog-agent/pkg/proto v0.77.3 // indirect

go.sum

@@ -22,8 +22,8 @@ cloud.google.com/go/storage v1.62.1 h1:Os0G3XbUbjZumkpDUf2Y0rLoXJTCF1kU2kWUujKYX
 cloud.google.com/go/storage v1.62.1/go.mod h1:cpYz/kRVZ+UQAF1uHeea10/9ewcRbxGoGNKsS9daSXA=
 cloud.google.com/go/trace v1.13.0 h1:RfqsqPOiSCG8ql50UZt5F65KrVa1zbY9mJrO7xvZfbE=
 cloud.google.com/go/trace v1.13.0/go.mod h1:r+bdAn16dKLSV1G2D5v3e58IlQlizfxWrUfjx7kM7X0=
-filippo.io/edwards25519 v1.1.1 h1:YpjwWWlNmGIDyXOn8zLzqiD+9TyIlPhGFG96P39uBpw=
-filippo.io/edwards25519 v1.1.1/go.mod h1:BxyFTGdWcka3PhytdK4V28tE5sGfRvvvRV7EaN4VDT4=
+filippo.io/edwards25519 v1.2.0 h1:crnVqOiS4jqYleHd9vaKZ+HKtHfllngJIiOpNpoJsjo=
+filippo.io/edwards25519 v1.2.0/go.mod h1:xzAOLCNug/yB62zG1bQ8uziwrIqIuxhctzJT18Q77mc=
 github.com/AdaLogics/go-fuzz-headers v0.0.0-20240806141605-e8a1dd7889d6 h1:He8afgbRMd7mFxO99hRNu+6tazq8nFF9lIwo9JFroBk=
 github.com/AdaLogics/go-fuzz-headers v0.0.0-20240806141605-e8a1dd7889d6/go.mod h1:8o94RPi1/7XTJvwPpRSzSUedZrtlirdB3r9Z20bi2f8=
 github.com/Azure/azure-pipeline-go v0.2.3 h1:7U9HBg1JFK3jHl5qmo4CTZKFTVgMwdFHMVtCdfBE21U=
@@ -156,6 +156,8 @@ github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
 github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
 github.com/bitfield/gotestdox v0.2.2 h1:x6RcPAbBbErKLnapz1QeAlf3ospg8efBsedU93CDsnE=
 github.com/bitfield/gotestdox v0.2.2/go.mod h1:D+gwtS0urjBrzguAkTM2wodsTQYFHdpx8eqRJ3N+9pY=
+github.com/block/mysql v0.0.0-20260906201522-a3178f8dca69 h1:rCWVZKT5PdrdfosvMavnnfUBAdtaM3iepvADt5pMSJI=
+github.com/block/mysql v0.0.0-20260906201522-a3178f8dca69/go.mod h1:KEo73lbxXs9cFlq+x3Z35UqGg3MTxAPfjDOR/ob/iik=
 github.com/bndr/gotabulate v1.1.2 h1:yC9izuZEphojb9r+KYL4W9IJKO/ceIO8HDwxMA24U4c=
 github.com/bndr/gotabulate v1.1.2/go.mod h1:0+8yUgaPTtLRTjf49E8oju7ojpU11YmXyvq1LbPAb3U=
 github.com/brianvoe/gofakeit/v7 v7.14.1 h1:a7fe3fonbj0cW3wgl5VwIKfZtiH9C3cLnwcIXWT7sow=

go/vt/topo/mysqltopo/main_test.go

@@ -26,7 +26,7 @@ import (
 	"path"
 	"testing"
 
-	"github.com/go-sql-driver/mysql"
+	"github.com/block/mysql"
 	"github.com/stretchr/testify/require"
 	"go.uber.org/goleak"
 
@@ -125,7 +125,7 @@ func createTestServer(t *testing.T, schemaName string) (*Server, string, func())
 		schemaName = generateRandomSchemaName()
 	}
 	cfg.DBName = "" // to create schema
-	baseDB, err := sql.Open("mysql", cfg.FormatDSN())
+	baseDB, err := sql.Open(driverName, cfg.FormatDSN())
 	require.NoError(t, err)
 
 	_, err = baseDB.Exec(fmt.Sprintf("CREATE DATABASE IF NOT EXISTS `%s`", schemaName))

go/vt/topo/mysqltopo/notification.go

@@ -29,7 +29,7 @@ import (
 	"sync/atomic"
 	"time"
 
-	mysqldriver "github.com/go-sql-driver/mysql"
+	mysqldriver "github.com/block/mysql"
 
 	"vitess.io/vitess/go/mysql"
 	"vitess.io/vitess/go/mysql/replication"
@@ -209,7 +209,7 @@ func newNotificationSystem(schemaName, serverAddr string) (*notificationSystem,
 		cfg.TLSConfig = "rds-topo"
 	}
 
-	db, err := sql.Open("mysql", cfg.FormatDSN())
+	db, err := sql.Open(driverName, cfg.FormatDSN())
 	if err != nil {
 		return nil, fmt.Errorf("failed to connect to MySQL: %v", err)
 	}
@@ -236,7 +236,7 @@ func newNotificationSystem(schemaName, serverAddr string) (*notificationSystem,
 	// Create connection parameters for binlog streaming
 	cfg.DBName = schemaName
 
-	// Parse host and port from cfg.Addr. The go-sql-driver/mysql DSN allows
+	// Parse host and port from cfg.Addr. The driver's DSN format allows
 	// addresses without a port (e.g. `tcp(localhost)/db`); fall back to the
 	// default MySQL port in that case.
 	host, portStr, err := net.SplitHostPort(cfg.Addr)

go/vt/topo/mysqltopo/notification_test.go

@@ -56,7 +56,7 @@ import (
 	"testing"
 	"time"
 
-	"github.com/go-sql-driver/mysql"
+	"github.com/block/mysql"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
@@ -765,7 +765,7 @@ func TestNotificationSystemReconnection(t *testing.T) {
 	require.Equal(t, initialData, current.Contents)
 
 	// Create a separate connection to monitor and kill connections
-	monitorDB, err := sql.Open("mysql", mySQLTopoTestAddr)
+	monitorDB, err := sql.Open(driverName, mySQLTopoTestAddr)
 	require.NoError(t, err)
 	defer monitorDB.Close()
 

go/vt/topo/mysqltopo/server.go

@@ -51,7 +51,14 @@ import (
 	"sync"
 	"time"
 
-	"github.com/go-sql-driver/mysql"
+	// Block's fork of go-sql-driver/mysql, registered as "block-mysql". strata
+	// links the fork for capabilities upstream does not carry; this package
+	// follows so that every *sql.DB it opens is served by the same driver whose
+	// *mysql.MySQLError type convertError below asserts on. That is a statement
+	// about this package, not about the binary: elsewhere in the repo, end-to-end
+	// tests still import upstream, and an error crossing from one of those would
+	// not match the assertion.
+	"github.com/block/mysql"
 	"github.com/spf13/pflag"
 
 	"vitess.io/vitess/go/mysql/sqlerror"
@@ -62,6 +69,13 @@ import (
 )
 
 const (
+	// driverName is the database/sql driver every connection in this package is
+	// opened with. It has to be block/mysql's registered name and not upstream's
+	// "mysql": convertError asserts on block/mysql's *mysql.MySQLError, and a
+	// *sql.DB opened with a different driver would return a type that assertion
+	// silently misses.
+	driverName = "block-mysql"
+
 	// DefaultSchema is the default database schema name for MySQL topo
 	DefaultSchema = "topo"
 
@@ -269,7 +283,7 @@ func connect(cfg *mysql.Config) (*sql.DB, error) {
 		cfg.TLSConfig = "rds-topo"
 	}
 
-	db, err := sql.Open("mysql", cfg.FormatDSN())
+	db, err := sql.Open(driverName, cfg.FormatDSN())
 	if err != nil {
 		return nil, fmt.Errorf("failed to connect to MySQL topo at %s (schema %q, user %q): %v", cfg.Addr, cfg.DBName, cfg.User, err)
 	}
@@ -539,7 +553,7 @@ func convertError(err error, path string) error {
 		return topo.NewError(topo.NoNode, path)
 	}
 
-	// Handle MySQL-specific errors. go-sql-driver returns *mysql.MySQLError,
+	// Handle MySQL-specific errors. block-mysql returns *mysql.MySQLError,
 	// which carries the server error number directly; its message format
 	// ("Error 1062 (23000): ...") is not recognized by
 	// sqlerror.NewSQLErrorFromError, so check the typed error first and only

go/vt/topo/mysqltopo/server_error_test.go

@@ -24,7 +24,7 @@ import (
 	"sync"
 	"testing"
 
-	"github.com/go-sql-driver/mysql"
+	"github.com/block/mysql"
 	"github.com/stretchr/testify/require"
 
 	"vitess.io/vitess/go/vt/topo"

go/vt/topo/mysqltopo/server_resolve_test.go

@@ -22,7 +22,7 @@ import (
 	"net"
 	"testing"
 
-	"github.com/go-sql-driver/mysql"
+	"github.com/block/mysql"
 	"github.com/stretchr/testify/require"
 )
 
@@ -36,7 +36,7 @@ func newRawSchema(t *testing.T) (baseDB *sql.DB, schemaDSN, schemaName string, c
 
 	schemaName = generateRandomSchemaName()
 	cfg.DBName = ""
-	baseDB, err = sql.Open("mysql", cfg.FormatDSN())
+	baseDB, err = sql.Open(driverName, cfg.FormatDSN())
 	require.NoError(t, err)
 	_, err = baseDB.Exec(fmt.Sprintf("CREATE DATABASE IF NOT EXISTS `%s`", schemaName))
 	require.NoError(t, err)