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

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 github.com/go-sql-driver/mysql.DeregisterTLSConfig in 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
Demonstrate these symbols/APIs:
  - github.com/go-sql-driver/mysql.DeregisterTLSConfig
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:f97a694d62d15e79e0deb4de08ca158a67aa2aa08c1faceb835b72be0333d0c4","contract":["mysql.RegisterTLSConfig registers a custom TLS config and allows DSN parsing with tls parameter","mysql.DeregisterTLSConfig removes a registered custom TLS configuration so that subsequent ParseDSN returns an unknown config error","mysql.DeregisterTLSConfig safely handles non-existent or unregistered TLS configuration keys without panic","mysql.RegisterTLSConfig allows re-registering and updating a TLS configuration under the same key after DeregisterTLSConfig","mysql.RegisterTLSConfig rejects reserved configuration key names including true, false, skip-verify, and preferred","mysql.Config.FormatDSN formats DSN with registered TLSConfig key correctly"],"goal":"verify github.com/go-sql-driver/mysql.DeregisterTLSConfig in 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,"symbols":["github.com/go-sql-driver/mysql.DeregisterTLSConfig"]},"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","symbols":["github.com/go-sql-driver/mysql.DeregisterTLSConfig"],"verifierAdapter":"golang@1"}

module sample-mysql-tls

go 1.22

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 (
	"crypto/tls"
	"fmt"

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

func main() {
	// Name for custom TLS configuration
	const customTLSKey = "custom-secure-tls"

	// Register a custom TLS configuration
	tlsConfig := &tls.Config{
		ServerName:         "db.example.com",
		InsecureSkipVerify: false,
	}
	if err := mysql.RegisterTLSConfig(customTLSKey, tlsConfig); err != nil {
		fmt.Printf("Failed to register TLS config: %v\n", err)
		return
	}
	fmt.Printf("Registered custom TLS configuration: %s\n", customTLSKey)

	// Configure MySQL connection using the registered custom TLS config
	cfg := mysql.NewConfig()
	cfg.User = "app_user"
	cfg.Passwd = "secret_pass"
	cfg.Net = "tcp"
	cfg.Addr = "127.0.0.1:3306"
	cfg.DBName = "example_db"
	cfg.TLSConfig = customTLSKey

	dsn := cfg.FormatDSN()
	fmt.Printf("Generated DSN with TLS: %s\n", dsn)

	// Deregister the custom TLS configuration when no longer needed
	mysql.DeregisterTLSConfig(customTLSKey)
	fmt.Printf("Deregistered custom TLS configuration: %s\n", customTLSKey)
}

{
  "schemaVersion": 1,
  "goal": "verify github.com/go-sql-driver/mysql.DeregisterTLSConfig in 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"
  ],
  "symbols": [
    "github.com/go-sql-driver/mysql.DeregisterTLSConfig"
  ],
  "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"
	"fmt"
	"os"

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

func main() {
	// Assertion 1: mysql.RegisterTLSConfig registers a custom TLS config and allows DSN parsing with tls parameter
	{
		tlsKey := "contract-tls-custom"
		tlsCfg := &tls.Config{
			ServerName: "db.example.com",
		}
		if err := mysql.RegisterTLSConfig(tlsKey, tlsCfg); err != nil {
			fmt.Fprintf(os.Stderr, "Assertion 1 failed: RegisterTLSConfig error: %v\n", err)
			os.Exit(1)
		}

		dsn := fmt.Sprintf("user:pass@tcp(127.0.0.1:3306)/testdb?tls=%s", tlsKey)
		cfg, err := mysql.ParseDSN(dsn)
		if err != nil {
			fmt.Fprintf(os.Stderr, "Assertion 1 failed: ParseDSN error: %v\n", err)
			os.Exit(1)
		}
		if cfg.TLSConfig != tlsKey {
			fmt.Fprintf(os.Stderr, "Assertion 1 failed: expected TLSConfig %q, got %q\n", tlsKey, cfg.TLSConfig)
			os.Exit(1)
		}
	}

	// Assertion 2: mysql.DeregisterTLSConfig removes a registered custom TLS configuration so that subsequent ParseDSN returns an unknown config error
	{
		tlsKey := "contract-tls-custom"
		mysql.DeregisterTLSConfig(tlsKey)

		dsn := fmt.Sprintf("user:pass@tcp(127.0.0.1:3306)/testdb?tls=%s", tlsKey)
		cfg, err := mysql.ParseDSN(dsn)
		if err == nil {
			fmt.Fprintf(os.Stderr, "Assertion 2 failed: expected ParseDSN error after DeregisterTLSConfig, got config: %v\n", cfg)
			os.Exit(1)
		}
	}

	// Assertion 3: mysql.DeregisterTLSConfig safely handles non-existent or unregistered TLS configuration keys without panic
	{
		nonExistentKey := "unregistered-tls-key-12345"
		mysql.DeregisterTLSConfig(nonExistentKey)
	}

	// Assertion 4: mysql.RegisterTLSConfig allows re-registering and updating a TLS configuration under the same key after DeregisterTLSConfig
	{
		tlsKey := "lifecycle-tls-key"
		cfg1 := &tls.Config{ServerName: "first.example.com"}
		if err := mysql.RegisterTLSConfig(tlsKey, cfg1); err != nil {
			fmt.Fprintf(os.Stderr, "Assertion 4 failed: first registration failed: %v\n", err)
			os.Exit(1)
		}

		dsn1 := fmt.Sprintf("user:pass@tcp(127.0.0.1:3306)/testdb?tls=%s", tlsKey)
		if _, err := mysql.ParseDSN(dsn1); err != nil {
			fmt.Fprintf(os.Stderr, "Assertion 4 failed: ParseDSN failed for registered key: %v\n", err)
			os.Exit(1)
		}

		mysql.DeregisterTLSConfig(tlsKey)

		if _, err := mysql.ParseDSN(dsn1); err == nil {
			fmt.Fprintf(os.Stderr, "Assertion 4 failed: expected error after DeregisterTLSConfig\n")
			os.Exit(1)
		}

		cfg2 := &tls.Config{ServerName: "second.example.com"}
		if err := mysql.RegisterTLSConfig(tlsKey, cfg2); err != nil {
			fmt.Fprintf(os.Stderr, "Assertion 4 failed: re-registration failed: %v\n", err)
			os.Exit(1)
		}

		if _, err := mysql.ParseDSN(dsn1); err != nil {
			fmt.Fprintf(os.Stderr, "Assertion 4 failed: ParseDSN failed after re-registration: %v\n", err)
			os.Exit(1)
		}

		mysql.DeregisterTLSConfig(tlsKey)
	}

	// Assertion 5: mysql.RegisterTLSConfig rejects reserved configuration key names including true, false, skip-verify, and preferred
	{
		reservedKeys := []string{"true", "false", "skip-verify", "preferred"}
		for _, rk := range reservedKeys {
			err := mysql.RegisterTLSConfig(rk, &tls.Config{})
			if err == nil {
				fmt.Fprintf(os.Stderr, "Assertion 5 failed: expected error for reserved key %q, got nil\n", rk)
				os.Exit(1)
			}
		}
	}

	// Assertion 6: mysql.Config.FormatDSN formats DSN with registered TLSConfig key correctly
	{
		tlsKey := "format-test-tls"
		if err := mysql.RegisterTLSConfig(tlsKey, &tls.Config{ServerName: "test.example.com"}); err != nil {
			fmt.Fprintf(os.Stderr, "Assertion 6 failed: RegisterTLSConfig error: %v\n", err)
			os.Exit(1)
		}

		cfg := mysql.NewConfig()
		cfg.User = "app_user"
		cfg.Passwd = "app_pass"
		cfg.Net = "tcp"
		cfg.Addr = "127.0.0.1:3306"
		cfg.DBName = "app_db"
		cfg.TLSConfig = tlsKey

		dsn := cfg.FormatDSN()
		parsed, err := mysql.ParseDSN(dsn)
		if err != nil {
			fmt.Fprintf(os.Stderr, "Assertion 6 failed: ParseDSN failed for formatted DSN: %v\n", err)
			os.Exit(1)
		}
		if parsed.TLSConfig != tlsKey {
			fmt.Fprintf(os.Stderr, "Assertion 6 failed: expected TLSConfig %q, got %q\n", tlsKey, parsed.TLSConfig)
			os.Exit(1)
		}

		mysql.DeregisterTLSConfig(tlsKey)
	}

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