github.com/jackc/pgx/v5 v5.10.0: CopyFromRows, CopyFromSlice, StrictNamedArgs

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/jackc/pgx/v5@v5.10.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/jackc/pgx/v5@v5.10.0
Constraints:
  - executionContext: node
Required runtime conditions:
  - ecosystem: npm
  - language: javascript
  - moduleSystem: cjs
  - packageManager: npm@11.8.0
  - runtime: node@24.13.1

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:a7b50162972e636d77093535ba7fd741f155ae901422b423eb95c90a99bc105c","contract":["pgx.CopyFromRows initializes a CopyFromSource from slice of row values","pgx.CopyFromRows Next and Values iterate through all rows in order","pgx.CopyFromSlice wraps slice length and row mapping function","pgx.CopyFromSlice correctly maps index to row values during Next iteration","pgx.CopyFromSlice returns false on Next when reaching end of slice with nil Err","pgx.StrictNamedArgs stores named parameters for parameterized queries"],"goal":"verify pkg:golang/github.com/jackc/pgx/v5@v5.10.0","kind":"HOW","packages":["pkg:golang/github.com/jackc/pgx/v5@v5.10.0"],"schemaVersion":1,"symbols":["github.com/jackc/pgx/v5.CopyFromRows","github.com/jackc/pgx/v5.CopyFromSlice","github.com/jackc/pgx/v5.StrictNamedArgs"]},"contractCommand":["go","run","./test"],"environment":{"arch":"x64","ecosystem":"golang","os":"windows","osVersionBucket":"11","packageManager":"go","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/github.com/jackc/pgx/v5@v5.10.0"],"schemaVersion":1,"symbols":["github.com/jackc/pgx/v5.CopyFromRows","github.com/jackc/pgx/v5.CopyFromSlice","github.com/jackc/pgx/v5.StrictNamedArgs"],"verifierAdapter":"golang@1"}

module sample

go 1.26.5

require (
	github.com/jackc/pgpassfile v1.0.0 // indirect
	github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761 // indirect
	github.com/jackc/pgx/v5 v5.10.0 // indirect
	golang.org/x/text v0.29.0 // indirect
)

github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
github.com/jackc/pgpassfile v1.0.0 h1:/6Hmqy13Ss2zCq62VdNG8tM1wchn8zjSGOBJ6icpsIM=
github.com/jackc/pgpassfile v1.0.0/go.mod h1:CEx0iS5ambNFdcRtxPj5JhEz+xB6uRky5eyVu/W2HEg=
github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761 h1:iCEnooe7UlwOQYpKFhBabPMi4aNAfoODPEFNiAnClxo=
github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761/go.mod h1:5TJZWKEWniPve33vlWYSoGYefn3gLQRzjfDlhSJ9ZKM=
github.com/jackc/pgx/v5 v5.10.0 h1:VhSvgU2jSli8o3AqIEOTJr7rZwAEUVo4E4XhR94Zfr0=
github.com/jackc/pgx/v5 v5.10.0/go.mod h1:mal1tBGAFfLHvZzaYh77YS/eC6IX9OWbRV1QIIM0Jn4=
github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
golang.org/x/text v0.29.0 h1:1neNs90w9YzJ9BocxfsQNHKuAT4pkghyXc4nhZ6sJvk=
golang.org/x/text v0.29.0/go.mod h1:7MhJOA9CD2qZyOKYazxdYMF85OwPdEr9jTtBpO7ydH4=
gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

package main

import (
	"fmt"
	"log"

	"github.com/jackc/pgx/v5"
)

type UserRecord struct {
	ID    int
	Name  string
	Email string
}

func main() {
	// 1. pgx.CopyFromRows creates a CopyFromSource from a 2D slice
	rawRows := [][]any{
		{1, "Alice", "alice@example.com"},
		{2, "Bob", "bob@example.com"},
	}
	rowsSource := pgx.CopyFromRows(rawRows)

	rowCount := 0
	for rowsSource.Next() {
		vals, err := rowsSource.Values()
		if err != nil {
			log.Fatalf("unexpected error reading row values: %v", err)
		}
		rowCount++
		fmt.Printf("CopyFromRows [%d]: %v\n", rowCount, vals)
	}
	if err := rowsSource.Err(); err != nil {
		log.Fatalf("CopyFromRows iterator error: %v", err)
	}

	// 2. pgx.CopyFromSlice creates a CopyFromSource from a typed slice with indexing func
	users := []UserRecord{
		{ID: 101, Name: "Charlie", Email: "charlie@example.com"},
		{ID: 102, Name: "Dana", Email: "dana@example.com"},
		{ID: 103, Name: "Eve", Email: "eve@example.com"},
	}
	sliceSource := pgx.CopyFromSlice(len(users), func(i int) ([]any, error) {
		return []any{users[i].ID, users[i].Name, users[i].Email}, nil
	})

	sliceCount := 0
	for sliceSource.Next() {
		vals, err := sliceSource.Values()
		if err != nil {
			log.Fatalf("unexpected error reading slice values: %v", err)
		}
		sliceCount++
		fmt.Printf("CopyFromSlice [%d]: %v\n", sliceCount, vals)
	}
	if err := sliceSource.Err(); err != nil {
		log.Fatalf("CopyFromSlice iterator error: %v", err)
	}

	// 3. pgx.StrictNamedArgs wraps query arguments requiring strict match
	strictArgs := pgx.StrictNamedArgs{
		"userId": 101,
		"status": "active",
	}
	fmt.Printf("StrictNamedArgs count: %d, userId: %v\n", len(strictArgs), strictArgs["userId"])
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:golang/github.com/jackc/pgx/v5@v5.10.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/jackc/pgx/v5@v5.10.0"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "cjs",
    "packageManager": "npm@11.8.0",
    "runtime": "node@24.13.1"
  }
}

package main

import (
	"errors"
	"fmt"
	"os"

	"github.com/jackc/pgx/v5"
)

type User struct {
	ID    int
	Name  string
	Email string
}

func main() {
	// Assertion 1 & 2: CopyFromRows iteration and value matching
	rawRows := [][]any{
		{1, "Alice", "alice@example.com"},
		{2, "Bob", "bob@example.com"},
	}
	rowsSrc := pgx.CopyFromRows(rawRows)

	if !rowsSrc.Next() {
		fmt.Fprintf(os.Stderr, "FAIL: expected CopyFromRows Next() to return true for row 1\n")
		os.Exit(1)
	}
	val1, err := rowsSrc.Values()
	if err != nil || len(val1) != 3 || val1[0] != 1 || val1[1] != "Alice" || val1[2] != "alice@example.com" {
		fmt.Fprintf(os.Stderr, "FAIL: CopyFromRows row 1 values mismatch: %v (err: %v)\n", val1, err)
		os.Exit(1)
	}

	if !rowsSrc.Next() {
		fmt.Fprintf(os.Stderr, "FAIL: expected CopyFromRows Next() to return true for row 2\n")
		os.Exit(1)
	}
	val2, err := rowsSrc.Values()
	if err != nil || len(val2) != 3 || val2[0] != 2 || val2[1] != "Bob" || val2[2] != "bob@example.com" {
		fmt.Fprintf(os.Stderr, "FAIL: CopyFromRows row 2 values mismatch: %v (err: %v)\n", val2, err)
		os.Exit(1)
	}

	if rowsSrc.Next() {
		fmt.Fprintf(os.Stderr, "FAIL: expected CopyFromRows Next() to return false at end\n")
		os.Exit(1)
	}
	if err := rowsSrc.Err(); err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: expected CopyFromRows Err() to be nil, got: %v\n", err)
		os.Exit(1)
	}

	// Assertion 3 & 4 & 5: CopyFromSlice mapping and iteration
	users := []User{
		{ID: 101, Name: "Charlie", Email: "charlie@example.com"},
		{ID: 102, Name: "Dana", Email: "dana@example.com"},
		{ID: 103, Name: "Eve", Email: "eve@example.com"},
	}
	sliceSrc := pgx.CopyFromSlice(len(users), func(i int) ([]any, error) {
		if i < 0 || i >= len(users) {
			return nil, errors.New("index out of range")
		}
		return []any{users[i].ID, users[i].Name, users[i].Email}, nil
	})

	expectedIDs := []int{101, 102, 103}
	for i, expectedID := range expectedIDs {
		if !sliceSrc.Next() {
			fmt.Fprintf(os.Stderr, "FAIL: expected CopyFromSlice Next() to return true for index %d\n", i)
			os.Exit(1)
		}
		vals, err := sliceSrc.Values()
		if err != nil || len(vals) != 3 || vals[0] != expectedID {
			fmt.Fprintf(os.Stderr, "FAIL: CopyFromSlice index %d mismatch: %v (err: %v)\n", i, vals, err)
			os.Exit(1)
		}
	}

	if sliceSrc.Next() {
		fmt.Fprintf(os.Stderr, "FAIL: expected CopyFromSlice Next() to return false after all elements\n")
		os.Exit(1)
	}
	if err := sliceSrc.Err(); err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: expected CopyFromSlice Err() to be nil, got: %v\n", err)
		os.Exit(1)
	}

	// Assertion 6: StrictNamedArgs parameter storage
	strictArgs := pgx.StrictNamedArgs{
		"userId": 101,
		"status": "active",
		"limit":  50,
	}
	if len(strictArgs) != 3 || strictArgs["userId"] != 101 || strictArgs["status"] != "active" || strictArgs["limit"] != 50 {
		fmt.Fprintf(os.Stderr, "FAIL: StrictNamedArgs mapping mismatch\n")
		os.Exit(1)
	}

	fmt.Println("PASS: all contract assertions passed for pkg:golang/github.com/jackc/pgx/v5@v5.10.0")
}