github.com/go-sql-driver/mysql v1.7.1

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify pkg:golang/github.com/go-sql-driver/mysql@v1.7.1
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/go-sql-driver/mysql@v1.7.1
Constraints:
  - executionContext: node
Required runtime conditions:
  - ecosystem: npm
  - language: javascript
  - moduleSystem: cjs
  - packageManager: npm@10.9.8
  - runtime: node@22.23.2

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:8ea85c61b60d2d5aa3dec9fbde5fc92caa4aa4bfc9958aa454aed8020a92e388","contract":["mysql.NewConfig initializes a Config struct with default network tcp, collation utf8mb4_general_ci, and default packet size","mysql.ParseDSN parses a full DSN string into a Config struct with user, password, network, address, database, and parameters","mysql.ParseDSN returns an error when given an invalid DSN string missing required structure","mysql.Config.FormatDSN formats a Config struct into a valid MySQL DSN connection string","mysql.Config.Clone creates an independent deep copy of a Config struct with copied parameter map","mysql.RegisterTLSConfig and DeregisterTLSConfig register and remove custom TLS configurations","mysql.NullTime implements sql.Scanner and driver.Valuer interfaces for handling nullable database timestamp values","mysql.MySQLError implements error interface returning formatted error number and message string"],"goal":"verify pkg:golang/github.com/go-sql-driver/mysql@v1.7.1","kind":"HOW","packages":["pkg:golang/github.com/go-sql-driver/mysql@v1.7.1"],"schemaVersion":1},"contractCommand":["go","run","./test"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/github.com/go-sql-driver/mysql@v1.7.1"],"schemaVersion":1,"subject":"pkg:golang/github.com/go-sql-driver/mysql@v1.7.1","verifierAdapter":"golang@1"}

module sample-mysql

go 1.26.6

require github.com/go-sql-driver/mysql v1.7.1

github.com/go-sql-driver/mysql v1.7.1 h1:lUIinVbN1DY0xBg0eMOzmmtGoHwWBbvnWubQUrtU8EI=
github.com/go-sql-driver/mysql v1.7.1/go.mod h1:OXbVy3sEdcQ2Doequ6Z5BW6fXNQTmx+9S1MCJN5yJMI=

package main

import (
	"fmt"
	"time"

	"github.com/go-sql-driver/mysql"
)

func main() {
	// Configure MySQL connection settings using mysql.NewConfig
	cfg := mysql.NewConfig()
	cfg.User = "app_user"
	cfg.Passwd = "secret_pass"
	cfg.Net = "tcp"
	cfg.Addr = "127.0.0.1:3306"
	cfg.DBName = "demo_db"
	cfg.Collation = "utf8mb4_general_ci"
	cfg.Loc = time.UTC
	cfg.ParseTime = true
	cfg.Timeout = 5 * time.Second

	// Format config to DSN string
	dsn := cfg.FormatDSN()
	fmt.Printf("Generated DSN: %s\n", dsn)

	// Parse DSN back into Config struct
	parsed, err := mysql.ParseDSN(dsn)
	if err != nil {
		fmt.Printf("Failed to parse DSN: %v\n", err)
		return
	}

	fmt.Printf("Parsed user: %s, db: %s, net: %s, addr: %s\n",
		parsed.User, parsed.DBName, parsed.Net, parsed.Addr)
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:golang/github.com/go-sql-driver/mysql@v1.7.1",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/go-sql-driver/mysql@v1.7.1"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "cjs",
    "packageManager": "npm@10.9.8",
    "runtime": "node@22.23.2"
  }
}

package main

import (
	"crypto/tls"
	"errors"
	"fmt"
	"os"
	"time"

	"github.com/go-sql-driver/mysql"
)

func main() {
	// Assertion 1: mysql.NewConfig initializes a Config struct with default network tcp, collation utf8mb4_general_ci, and default packet size
	{
		cfg := mysql.NewConfig()
		if cfg == nil {
			fmt.Fprintf(os.Stderr, "Assertion 1 failed: NewConfig returned nil\n")
			os.Exit(1)
		}
		if cfg.Collation != "utf8mb4_general_ci" {
			fmt.Fprintf(os.Stderr, "Assertion 1 failed: expected collation utf8mb4_general_ci, got %s\n", cfg.Collation)
			os.Exit(1)
		}
		if cfg.Loc != time.UTC {
			fmt.Fprintf(os.Stderr, "Assertion 1 failed: expected UTC location, got %v\n", cfg.Loc)
			os.Exit(1)
		}
		if !cfg.AllowNativePasswords {
			fmt.Fprintf(os.Stderr, "Assertion 1 failed: expected AllowNativePasswords to be true\n")
			os.Exit(1)
		}
		if !cfg.CheckConnLiveness {
			fmt.Fprintf(os.Stderr, "Assertion 1 failed: expected CheckConnLiveness to be true\n")
			os.Exit(1)
		}
		if cfg.MaxAllowedPacket <= 0 {
			fmt.Fprintf(os.Stderr, "Assertion 1 failed: expected positive MaxAllowedPacket, got %d\n", cfg.MaxAllowedPacket)
			os.Exit(1)
		}
	}

	// Assertion 2: mysql.ParseDSN parses a full DSN string into a Config struct with user, password, network, address, database, and parameters
	{
		raw := "sample_user:secret_pass@tcp(127.0.0.1:3306)/testdb?charset=utf8mb4&parseTime=true&timeout=5s"
		cfg, err := mysql.ParseDSN(raw)
		if err != nil {
			fmt.Fprintf(os.Stderr, "Assertion 2 failed: ParseDSN error: %v\n", err)
			os.Exit(1)
		}
		if cfg.User != "sample_user" || cfg.Passwd != "secret_pass" {
			fmt.Fprintf(os.Stderr, "Assertion 2 failed: user/passwd mismatch: %s / %s\n", cfg.User, cfg.Passwd)
			os.Exit(1)
		}
		if cfg.Net != "tcp" || cfg.Addr != "127.0.0.1:3306" {
			fmt.Fprintf(os.Stderr, "Assertion 2 failed: net/addr mismatch: %s / %s\n", cfg.Net, cfg.Addr)
			os.Exit(1)
		}
		if cfg.DBName != "testdb" {
			fmt.Fprintf(os.Stderr, "Assertion 2 failed: db name mismatch: %s\n", cfg.DBName)
			os.Exit(1)
		}
		if !cfg.ParseTime {
			fmt.Fprintf(os.Stderr, "Assertion 2 failed: expected ParseTime true\n")
			os.Exit(1)
		}
		if cfg.Timeout != 5*time.Second {
			fmt.Fprintf(os.Stderr, "Assertion 2 failed: expected timeout 5s, got %v\n", cfg.Timeout)
			os.Exit(1)
		}
	}

	// Assertion 3: mysql.ParseDSN returns an error when given an invalid DSN string missing required structure
	{
		invalidDSN := "invalid_dsn_without_slash"
		cfg, err := mysql.ParseDSN(invalidDSN)
		if err == nil {
			fmt.Fprintf(os.Stderr, "Assertion 3 failed: expected error for invalid DSN, got config: %v\n", cfg)
			os.Exit(1)
		}
	}

	// Assertion 4: mysql.Config.FormatDSN formats a Config struct into a valid MySQL DSN connection string
	{
		cfg := mysql.NewConfig()
		cfg.User = "custom_user"
		cfg.Passwd = "custom_pass"
		cfg.Net = "tcp"
		cfg.Addr = "127.0.0.1:3307"
		cfg.DBName = "custom_db"
		cfg.ParseTime = true

		dsn := cfg.FormatDSN()
		parsed, err := mysql.ParseDSN(dsn)
		if err != nil {
			fmt.Fprintf(os.Stderr, "Assertion 4 failed: cannot re-parse formatted DSN: %v (dsn: %s)\n", err, dsn)
			os.Exit(1)
		}
		if parsed.User != cfg.User || parsed.Passwd != cfg.Passwd || parsed.DBName != cfg.DBName || parsed.Addr != cfg.Addr || parsed.ParseTime != cfg.ParseTime {
			fmt.Fprintf(os.Stderr, "Assertion 4 failed: round-trip mismatch\n")
			os.Exit(1)
		}
	}

	// Assertion 5: mysql.Config.Clone creates an independent deep copy of a Config struct with copied parameter map
	{
		orig := mysql.NewConfig()
		orig.User = "original_user"
		orig.Params = map[string]string{
			"key1": "val1",
		}
		cloned := orig.Clone()
		if cloned.User != orig.User {
			fmt.Fprintf(os.Stderr, "Assertion 5 failed: user mismatch in clone\n")
			os.Exit(1)
		}
		cloned.Params["key1"] = "modified"
		cloned.Params["key2"] = "val2"
		if orig.Params["key1"] != "val1" || len(orig.Params) != 1 {
			fmt.Fprintf(os.Stderr, "Assertion 5 failed: clone is not deep copy, orig modified\n")
			os.Exit(1)
		}
	}

	// Assertion 6: mysql.RegisterTLSConfig and DeregisterTLSConfig register and remove custom TLS configurations
	{
		tlsKey := "test-custom-tls"
		tlsCfg := &tls.Config{
			ServerName: "db.example.com",
		}
		if err := mysql.RegisterTLSConfig(tlsKey, tlsCfg); err != nil {
			fmt.Fprintf(os.Stderr, "Assertion 6 failed: RegisterTLSConfig error: %v\n", err)
			os.Exit(1)
		}
		dsn := fmt.Sprintf("user:pass@tcp(127.0.0.1:3306)/db?tls=%s", tlsKey)
		cfg, err := mysql.ParseDSN(dsn)
		if err != nil {
			fmt.Fprintf(os.Stderr, "Assertion 6 failed: ParseDSN with custom TLS failed: %v\n", err)
			os.Exit(1)
		}
		if cfg.TLSConfig != tlsKey {
			fmt.Fprintf(os.Stderr, "Assertion 6 failed: expected TLSConfig %s, got %s\n", tlsKey, cfg.TLSConfig)
			os.Exit(1)
		}
		mysql.DeregisterTLSConfig(tlsKey)
	}

	// Assertion 7: mysql.NullTime implements sql.Scanner and driver.Valuer interfaces for handling nullable database timestamp values
	{
		var nt mysql.NullTime
		if err := nt.Scan(nil); err != nil {
			fmt.Fprintf(os.Stderr, "Assertion 7 failed: Scan(nil) error: %v\n", err)
			os.Exit(1)
		}
		if nt.Valid {
			fmt.Fprintf(os.Stderr, "Assertion 7 failed: expected Valid false for nil\n")
			os.Exit(1)
		}
		val, err := nt.Value()
		if err != nil || val != nil {
			fmt.Fprintf(os.Stderr, "Assertion 7 failed: Value() for invalid NullTime expected nil, got %v, err: %v\n", val, err)
			os.Exit(1)
		}

		timeStr := "2026-08-23 12:34:56"
		if err := nt.Scan(timeStr); err != nil {
			fmt.Fprintf(os.Stderr, "Assertion 7 failed: Scan string error: %v\n", err)
			os.Exit(1)
		}
		if !nt.Valid {
			fmt.Fprintf(os.Stderr, "Assertion 7 failed: expected Valid true for valid string\n")
			os.Exit(1)
		}
		expectedTime := time.Date(2026, 8, 23, 12, 34, 56, 0, time.UTC)
		if !nt.Time.Equal(expectedTime) {
			fmt.Fprintf(os.Stderr, "Assertion 7 failed: time mismatch: expected %v, got %v\n", expectedTime, nt.Time)
			os.Exit(1)
		}
		val2, err := nt.Value()
		if err != nil {
			fmt.Fprintf(os.Stderr, "Assertion 7 failed: Value() error: %v\n", err)
			os.Exit(1)
		}
		tVal, ok := val2.(time.Time)
		if !ok || !tVal.Equal(expectedTime) {
			fmt.Fprintf(os.Stderr, "Assertion 7 failed: Value() returned %v, expected time.Time\n", val2)
			os.Exit(1)
		}
	}

	// Assertion 8: mysql.MySQLError implements error interface returning formatted error number and message string
	{
		myErr := &mysql.MySQLError{
			Number:   1045,
			SQLState: [5]byte{'2', '8', '0', '0', '0'},
			Message:  "Access denied for user",
		}
		errMsg := myErr.Error()
		expectedMsg := "Error 1045 (28000): Access denied for user"
		if errMsg != expectedMsg {
			fmt.Fprintf(os.Stderr, "Assertion 8 failed: expected %q, got %q\n", expectedMsg, errMsg)
			os.Exit(1)
		}

		targetErr := &mysql.MySQLError{Number: 1045}
		if !errors.Is(myErr, targetErr) {
			fmt.Fprintf(os.Stderr, "Assertion 8 failed: errors.Is expected true for same error number\n")
			os.Exit(1)
		}
	}

	fmt.Println("All contract assertions passed.")
}