feat(mysql)!: promote to v1.0.0 — BeginTx with isolation levels, Stats, bump all deps to v1.0.0

Add BeginTx(ctx, *sql.TxOptions) to Client interface for explicit transaction isolation
level control; Begin refactored as a convenience wrapper calling BeginTx(ctx, nil).
Add Stats() sql.DBStats to Component interface for connection pool observability.
Bump all micro-lib dependencies (logz, health, launcher, xerrors) from v0.9.0 to v1.0.0.
API committed as stable.

CHANGELOG.md

@@ -5,6 +5,25 @@ All notable changes to this module will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this module adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [1.0.0] — 2026-05-12
+
+### Added
+
+- `Client.BeginTx(ctx context.Context, opts *sql.TxOptions) (Tx, error)` — starts a transaction with explicit isolation level and read-only options; accepts any `*sql.TxOptions` supported by `database/sql`.
+- `Component.Stats() sql.DBStats` — returns connection pool metrics (`OpenConnections`, `WaitCount`, `WaitDuration`, etc.) for observability and alerting; returns zero value when called before `OnInit`.
+
+### Changed
+
+- `Client.Begin(ctx context.Context) (Tx, error)` — refactored as a convenience wrapper calling `BeginTx(ctx, nil)`; behavior is identical, no breaking change.
+- All micro-lib dependencies bumped from v0.9.1 to v1.0.0: `logz`, `health`, `launcher`, `xerrors`.
+
+### Unchanged
+
+All other API (`Executor`, `Tx`, `Client`, `Component`, `UnitOfWork`, `Config`, `New`,
+`NewUnitOfWork`, `HandleError`) is API-compatible with v0.9.1.
+
+[1.0.0]: https://code.nochebuena.dev/go/mysql/releases/tag/v1.0.0
+
 ## [0.9.1] - 2026-03-20
 
 ### Added
@@ -23,6 +42,8 @@ and this module adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.
 - **Backward compatible.** Existing `Config` literals that do not set `Charset`, `Loc`, or `ParseTime` produce the same DSN as v0.9.0 (`charset=utf8mb4&loc=UTC&parseTime=true`).
 - **Collation via DSN is not supported.** `go-sql-driver` v1.8.x negotiates the collation using a 1-byte handshake ID (max 255). MariaDB 11.4+ collations such as `utf8mb4_uca1400_as_cs` carry IDs > 255 and will cause a connection error if set in the DSN. Set the desired collation in schema migrations at the database/table level.
 
+[0.9.1]: https://code.nochebuena.dev/go/mysql/releases/tag/v0.9.1
+
 ## [0.9.0] - 2026-03-18
 
 ### Added
@@ -49,5 +70,4 @@ and this module adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.
 - The module is structurally parallel to `postgres` but uses `database/sql` types throughout; the two modules are intentionally type-incompatible.
 - MySQL error codes are matched by numeric constant via `MySQLError.Number`, not by string parsing, for stability across MySQL and MariaDB versions.
 
-[0.9.1]: https://code.nochebuena.dev/go/mysql/releases/tag/v0.9.1
 [0.9.0]: https://code.nochebuena.dev/go/mysql/releases/tag/v0.9.0

go.mod

@@ -3,10 +3,10 @@ module code.nochebuena.dev/go/mysql
 go 1.25
 
 require (
-	code.nochebuena.dev/go/health v0.9.0
-	code.nochebuena.dev/go/launcher v0.9.0
-	code.nochebuena.dev/go/logz v0.9.0
-	code.nochebuena.dev/go/xerrors v0.9.0
+	code.nochebuena.dev/go/health v1.0.0
+	code.nochebuena.dev/go/launcher v1.0.0
+	code.nochebuena.dev/go/logz v1.0.0
+	code.nochebuena.dev/go/xerrors v1.0.0
 	github.com/go-sql-driver/mysql v1.8.1
 )
 

go.sum

@@ -1,11 +1,11 @@
-code.nochebuena.dev/go/health v0.9.0 h1:x0UKjC7CHAE3AgwyFzCyjmGJIjoLBBxeOHxXuqpbKwI=
-code.nochebuena.dev/go/health v0.9.0/go.mod h1:f3IsNtU60JSn5yXmBBh9XOvr5pRyEah5+wS4tjDQZso=
-code.nochebuena.dev/go/launcher v0.9.0 h1:dJHonA9Xm03AQKK0919FJaQn9ZKHZ+RZfB9yxjnx3TA=
-code.nochebuena.dev/go/launcher v0.9.0/go.mod h1:IBtntmbnyddukjEhxlc7Ysdzz9nZsnd9+8FzAIHt77g=
-code.nochebuena.dev/go/logz v0.9.0 h1:wfV7vtI4V/8ED7Hm31Fbql7Y5iOGrlHN4X8Z5ajTZZE=
-code.nochebuena.dev/go/logz v0.9.0/go.mod h1:qODhSbKb+tWE7rdhHLcKweiP5CgwIaWoZxadCT3bQV8=
-code.nochebuena.dev/go/xerrors v0.9.0 h1:8wrDto7e44ZW1YPOnT6JrxYXTqnvNuKpAO1/5bcT4TE=
-code.nochebuena.dev/go/xerrors v0.9.0/go.mod h1:mtXo7xscBreCB7w7smlBP5Onv8H1HVohCvF0I/VXbAY=
+code.nochebuena.dev/go/health v1.0.0 h1:MOlvrTj8Go0sVgczo1O68nBplZ2DM9Td4aBJqL4HI10=
+code.nochebuena.dev/go/health v1.0.0/go.mod h1:f3IsNtU60JSn5yXmBBh9XOvr5pRyEah5+wS4tjDQZso=
+code.nochebuena.dev/go/launcher v1.0.0 h1:Jwqdc/1XX9do5CIzZpayC8wqhqiHsbiYJSIrLIpoaZ4=
+code.nochebuena.dev/go/launcher v1.0.0/go.mod h1:gD2D+aPKfsKNUsT6YkvjszB2fy0qAwvBRXVAtWa4mxo=
+code.nochebuena.dev/go/logz v1.0.0 h1:DpNvLuVFqyLSVKxaRa799sG8RpHnm1j6dhu4pKiFOvY=
+code.nochebuena.dev/go/logz v1.0.0/go.mod h1:qODhSbKb+tWE7rdhHLcKweiP5CgwIaWoZxadCT3bQV8=
+code.nochebuena.dev/go/xerrors v1.0.0 h1:si24SFGa7cHwAxbu75AAEB+a3qRmF118F/BM2SFI7VI=
+code.nochebuena.dev/go/xerrors v1.0.0/go.mod h1:mtXo7xscBreCB7w7smlBP5Onv8H1HVohCvF0I/VXbAY=
 filippo.io/edwards25519 v1.1.0 h1:FNf4tywRC1HmFuKW5xopWpigGjJKiJSV0Cqo0cJWDaA=
 filippo.io/edwards25519 v1.1.0/go.mod h1:BxyFTGdWcka3PhytdK4V28tE5sGfRvvvRV7EaN4VDT4=
 github.com/go-sql-driver/mysql v1.8.1 h1:LedoTUt/eveggdHS9qUFC1EFSa8bU2+1pZjSRpvNJ1Y=

mysql.go

@@ -33,6 +33,7 @@ type Tx interface {
 type Client interface {
 	GetExecutor(ctx context.Context) Executor
 	Begin(ctx context.Context) (Tx, error)
+	BeginTx(ctx context.Context, opts *sql.TxOptions) (Tx, error)
 	Ping(ctx context.Context) error
 	HandleError(err error) error
 }
@@ -42,6 +43,7 @@ type Component interface {
 	launcher.Component
 	health.Checkable
 	Client
+	Stats() sql.DBStats
 }
 
 // UnitOfWork wraps operations in a single database transaction.
@@ -192,20 +194,34 @@ func (c *mysqlComponent) GetExecutor(ctx context.Context) Executor {
 	return db
 }
 
-func (c *mysqlComponent) Begin(ctx context.Context) (Tx, error) {
+func (c *mysqlComponent) BeginTx(ctx context.Context, opts *sql.TxOptions) (Tx, error) {
 	c.mu.RLock()
 	db := c.db
 	c.mu.RUnlock()
 	if db == nil {
 		return nil, fmt.Errorf("mysql: not initialized")
 	}
-	tx, err := db.BeginTx(ctx, nil)
+	tx, err := db.BeginTx(ctx, opts)
 	if err != nil {
 		return nil, err
 	}
 	return &mysqlTx{Tx: tx}, nil
 }
 
+func (c *mysqlComponent) Begin(ctx context.Context) (Tx, error) {
+	return c.BeginTx(ctx, nil)
+}
+
+func (c *mysqlComponent) Stats() sql.DBStats {
+	c.mu.RLock()
+	db := c.db
+	c.mu.RUnlock()
+	if db == nil {
+		return sql.DBStats{}
+	}
+	return db.Stats()
+}
+
 func (c *mysqlComponent) ExecContext(ctx context.Context, query string, args ...any) (sql.Result, error) {
 	c.mu.RLock()
 	db := c.db

mysql_test.go

@@ -99,9 +99,10 @@ func (m *mockTx) Rollback() error
 
 type mockClient struct{ tx *mockTx }
 
-func (m *mockClient) Begin(ctx context.Context) (Tx, error)        { return m.tx, nil }
-func (m *mockClient) Ping(ctx context.Context) error               { return nil }
-func (m *mockClient) HandleError(err error) error                  { return HandleError(err) }
+func (m *mockClient) Begin(ctx context.Context) (Tx, error)                          { return m.tx, nil }
+func (m *mockClient) BeginTx(ctx context.Context, opts *sql.TxOptions) (Tx, error)   { return m.tx, nil }
+func (m *mockClient) Ping(ctx context.Context) error                                 { return nil }
+func (m *mockClient) HandleError(err error) error                                    { return HandleError(err) }
 func (m *mockClient) GetExecutor(ctx context.Context) Executor {
 	if tx, ok := ctx.Value(ctxTxKey{}).(Executor); ok {
 		return tx
@@ -143,6 +144,24 @@ func TestUnitOfWork_InjectsExecutor(t *testing.T) {
 	}
 }
 
+// --- BeginTx / Stats ---
+
+func TestComponent_BeginTx_NilDB(t *testing.T) {
+	c := &mysqlComponent{logger: newLogger()}
+	_, err := c.BeginTx(context.Background(), nil)
+	if err == nil {
+		t.Error("expected error for nil db")
+	}
+}
+
+func TestComponent_Stats_NilDB(t *testing.T) {
+	c := &mysqlComponent{logger: newLogger()}
+	stats := c.Stats()
+	if stats.MaxOpenConnections != 0 || stats.OpenConnections != 0 {
+		t.Errorf("expected zero DBStats, got %+v", stats)
+	}
+}
+
 // --- helpers ---
 
 func assertCode(t *testing.T, err error, want xerrors.Code) {