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

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.NullTime 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.NullTime
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:a2b05b8d13498cbe50b6f239125dbbd28fcf46353f3898a832a41d3856f1d8d5","contract":["mysql.NullTime represents nullable time values with Time and Valid fields","mysql.NullTime.Scan sets Valid to false and Time to zero time when given nil","mysql.NullTime.Scan sets Time and Valid to true when given a time.Time value","mysql.NullTime.Scan parses valid date and datetime byte slices or strings into Time with Valid true","mysql.NullTime.Scan returns an error when given invalid time strings or unsupported data types","mysql.NullTime.Value returns nil when Valid is false and returns Time when Valid is true implementing driver.Valuer"],"goal":"verify github.com/go-sql-driver/mysql.NullTime 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.NullTime"]},"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.NullTime"],"verifierAdapter":"golang@1"}

module example.com/sample

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 (
	"database/sql/driver"
	"fmt"
	"time"

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

func main() {
	// Initialize a NullTime representing a valid timestamp
	nt := mysql.NullTime{
		Time:  time.Date(2026, 8, 26, 12, 0, 0, 0, time.UTC),
		Valid: true,
	}

	val, err := nt.Value()
	if err != nil {
		panic(err)
	}
	fmt.Printf("Valid NullTime value: %v\n", val)

	// Scan a nil value to represent a NULL database column
	var nullVal mysql.NullTime
	if err := nullVal.Scan(nil); err != nil {
		panic(err)
	}
	fmt.Printf("Null NullTime valid: %v\n", nullVal.Valid)

	// Verify driver.Valuer interface compatibility
	var _ driver.Valuer = nt
}

{
  "schemaVersion": 1,
  "goal": "verify github.com/go-sql-driver/mysql.NullTime 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.NullTime"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "cjs",
    "packageManager": "npm@10.9.8",
    "runtime": "node@22.23.2"
  }
}

package main

import (
	"database/sql/driver"
	"fmt"
	"os"
	"time"

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

func main() {
	// Assertion 1: mysql.NullTime represents nullable time values with Time and Valid fields
	{
		testTime := time.Date(2026, 8, 26, 10, 0, 0, 0, time.UTC)
		nt := mysql.NullTime{
			Time:  testTime,
			Valid: true,
		}
		if !nt.Time.Equal(testTime) {
			fmt.Fprintf(os.Stderr, "Assertion 1 failed: expected Time %v, got %v\n", testTime, nt.Time)
			os.Exit(1)
		}
		if !nt.Valid {
			fmt.Fprintf(os.Stderr, "Assertion 1 failed: expected Valid true, got false\n")
			os.Exit(1)
		}
	}

	// Assertion 2: mysql.NullTime.Scan sets Valid to false and Time to zero time when given nil
	{
		nt := mysql.NullTime{
			Time:  time.Date(2026, 8, 26, 10, 0, 0, 0, time.UTC),
			Valid: true,
		}
		if err := nt.Scan(nil); err != nil {
			fmt.Fprintf(os.Stderr, "Assertion 2 failed: unexpected error on Scan(nil): %v\n", err)
			os.Exit(1)
		}
		if nt.Valid {
			fmt.Fprintf(os.Stderr, "Assertion 2 failed: expected Valid false, got true\n")
			os.Exit(1)
		}
		if !nt.Time.IsZero() {
			fmt.Fprintf(os.Stderr, "Assertion 2 failed: expected zero Time, got %v\n", nt.Time)
			os.Exit(1)
		}
	}

	// Assertion 3: mysql.NullTime.Scan sets Time and Valid to true when given a time.Time value
	{
		var nt mysql.NullTime
		expectedTime := time.Date(2026, 1, 15, 8, 30, 0, 0, time.UTC)
		if err := nt.Scan(expectedTime); err != nil {
			fmt.Fprintf(os.Stderr, "Assertion 3 failed: unexpected error on Scan(time.Time): %v\n", err)
			os.Exit(1)
		}
		if !nt.Valid {
			fmt.Fprintf(os.Stderr, "Assertion 3 failed: expected Valid true, got false\n")
			os.Exit(1)
		}
		if !nt.Time.Equal(expectedTime) {
			fmt.Fprintf(os.Stderr, "Assertion 3 failed: expected Time %v, got %v\n", expectedTime, nt.Time)
			os.Exit(1)
		}
	}

	// Assertion 4: mysql.NullTime.Scan parses valid date and datetime byte slices or strings into Time with Valid true
	{
		var ntString mysql.NullTime
		if err := ntString.Scan("2026-08-26 15:04:05"); err != nil {
			fmt.Fprintf(os.Stderr, "Assertion 4 failed: Scan string failed: %v\n", err)
			os.Exit(1)
		}
		if !ntString.Valid {
			fmt.Fprintf(os.Stderr, "Assertion 4 failed: expected Valid true for string datetime\n")
			os.Exit(1)
		}
		expectedTime := time.Date(2026, 8, 26, 15, 4, 5, 0, time.UTC)
		if !ntString.Time.Equal(expectedTime) {
			fmt.Fprintf(os.Stderr, "Assertion 4 failed: expected %v, got %v\n", expectedTime, ntString.Time)
			os.Exit(1)
		}

		var ntBytes mysql.NullTime
		if err := ntBytes.Scan([]byte("2026-08-26 15:04:05.123456")); err != nil {
			fmt.Fprintf(os.Stderr, "Assertion 4 failed: Scan byte slice failed: %v\n", err)
			os.Exit(1)
		}
		if !ntBytes.Valid {
			fmt.Fprintf(os.Stderr, "Assertion 4 failed: expected Valid true for byte slice datetime\n")
			os.Exit(1)
		}
		expectedNano := time.Date(2026, 8, 26, 15, 4, 5, 123456000, time.UTC)
		if !ntBytes.Time.Equal(expectedNano) {
			fmt.Fprintf(os.Stderr, "Assertion 4 failed: expected %v, got %v\n", expectedNano, ntBytes.Time)
			os.Exit(1)
		}
	}

	// Assertion 5: mysql.NullTime.Scan returns an error when given invalid time strings or unsupported data types
	{
		var nt mysql.NullTime
		if err := nt.Scan("invalid-date-string"); err == nil {
			fmt.Fprintf(os.Stderr, "Assertion 5 failed: expected error scanning invalid string, got nil\n")
			os.Exit(1)
		}

		if err := nt.Scan(12345); err == nil {
			fmt.Fprintf(os.Stderr, "Assertion 5 failed: expected error scanning unsupported int type, got nil\n")
			os.Exit(1)
		}
	}

	// Assertion 6: mysql.NullTime.Value returns nil when Valid is false and returns Time when Valid is true implementing driver.Valuer
	{
		invalidNT := mysql.NullTime{Valid: false}
		val, err := invalidNT.Value()
		if err != nil {
			fmt.Fprintf(os.Stderr, "Assertion 6 failed: unexpected error on invalid NullTime.Value(): %v\n", err)
			os.Exit(1)
		}
		if val != nil {
			fmt.Fprintf(os.Stderr, "Assertion 6 failed: expected nil driver.Value, got %v\n", val)
			os.Exit(1)
		}

		now := time.Date(2026, 8, 26, 12, 0, 0, 0, time.UTC)
		validNT := mysql.NullTime{Time: now, Valid: true}
		val, err = validNT.Value()
		if err != nil {
			fmt.Fprintf(os.Stderr, "Assertion 6 failed: unexpected error on valid NullTime.Value(): %v\n", err)
			os.Exit(1)
		}
		tVal, ok := val.(time.Time)
		if !ok || !tVal.Equal(now) {
			fmt.Fprintf(os.Stderr, "Assertion 6 failed: expected time.Time %v, got %v\n", now, val)
			os.Exit(1)
		}

		var _ driver.Valuer = validNT
	}

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