github.com/google/pprof v0.0.0-20210407192527-94a9f03dee38: profile.Merge, profile.Profile.CheckValid, profile.Profile.Copy

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/google/pprof@v0.0.0-20210407192527-94a9f03dee38
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/google/pprof@v0.0.0-20210407192527-94a9f03dee38
Demonstrate these symbols/APIs:
  - github.com/google/pprof/profile.Merge
  - github.com/google/pprof/profile.Profile.CheckValid
  - github.com/google/pprof/profile.Profile.Copy
  - github.com/google/pprof/profile.Profile.Scale

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:sha256:9c17c24d2a9ca331d2e949355e6e9d3563a4f559c963f4f65eda132ae768d3cc","contract":["profile.Merge combines multiple profiles of identical structure by aggregating sample values","profile.Profile.Copy creates an independent deep copy of the profile","profile.Profile.Scale multiplies all sample values by a scaling factor"],"goal":"verify pkg:golang/github.com/google/pprof@v0.0.0-20210407192527-94a9f03dee38","kind":"HOW","packages":["pkg:golang/github.com/google/pprof@v0.0.0-20210407192527-94a9f03dee38"],"schemaVersion":1,"symbols":["github.com/google/pprof/profile.Merge","github.com/google/pprof/profile.Profile.CheckValid","github.com/google/pprof/profile.Profile.Copy","github.com/google/pprof/profile.Profile.Scale"]},"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/google/pprof@v0.0.0-20210407192527-94a9f03dee38"],"schemaVersion":1,"subject":"pkg:golang/github.com/google/pprof@v0.0.0-20210407192527-94a9f03dee38","symbols":["github.com/google/pprof/profile.Merge","github.com/google/pprof/profile.Profile.CheckValid","github.com/google/pprof/profile.Profile.Copy","github.com/google/pprof/profile.Profile.Scale"],"verifierAdapter":"golang@1"}

module sample

go 1.22

require github.com/google/pprof v0.0.0-20210407192527-94a9f03dee38

github.com/chzyer/logex v1.1.10/go.mod h1:+Ywpsq7O8HXn0nuIou7OrIPyXbp3wmkHB+jjWRnGsAI=
github.com/chzyer/readline v0.0.0-20180603132655-2972be24d48e/go.mod h1:nSuG5e5PlCu98SY8svDHJxuZscDgtXS6KTTbou5AhLI=
github.com/chzyer/test v0.0.0-20180213035817-a1ea475d72b1/go.mod h1:Q3SI9o4m/ZMnBNeIyt5eFwwo7qiLfzFZmjNmxjkiQlU=
github.com/google/pprof v0.0.0-20210407192527-94a9f03dee38 h1:yAJXTCF9TqKcTiHJAE8dj7HMvPfh66eeA2JYW7eFpSE=
github.com/google/pprof v0.0.0-20210407192527-94a9f03dee38/go.mod h1:kpwsk12EmLew5upagYY7GY0pfYCcupk39gWOCRROcvE=
github.com/ianlancetaylor/demangle v0.0.0-20200824232613-28f6c0f3b639/go.mod h1:aSSvb/t6k1mPoxDqO4vJh6VOCGPwU4O0C2/Eqndh1Sc=
golang.org/x/sys v0.0.0-20191204072324-ce4227a45e2e/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=

package sample

import (
	"fmt"

	"github.com/google/pprof/profile"
)

// CreateProfile creates a valid profile with sample types, function, location, and a sample.
func CreateProfile(funcName, fileName string, line int64, sampleCount, cpuNanos int64) *profile.Profile {
	fn := &profile.Function{
		ID:         1,
		Name:       funcName,
		SystemName: funcName,
		Filename:   fileName,
		StartLine:  line,
	}

	loc := &profile.Location{
		ID: 1,
		Line: []profile.Line{
			{
				Function: fn,
				Line:     line + 2,
			},
		},
	}

	p := &profile.Profile{
		SampleType: []*profile.ValueType{
			{Type: "samples", Unit: "count"},
			{Type: "cpu", Unit: "nanoseconds"},
		},
		PeriodType: &profile.ValueType{Type: "cpu", Unit: "nanoseconds"},
		Period:     10000000,
		Function:   []*profile.Function{fn},
		Location:   []*profile.Location{loc},
		Sample: []*profile.Sample{
			{
				Location: []*profile.Location{loc},
				Value:    []int64{sampleCount, cpuNanos},
			},
		},
	}
	return p
}

// MergeProfiles merges multiple profiles into a single combined profile.
func MergeProfiles(profiles []*profile.Profile) (*profile.Profile, error) {
	if len(profiles) == 0 {
		return nil, fmt.Errorf("no profiles provided")
	}
	return profile.Merge(profiles)
}

// CopyAndScale clones a profile and scales all sample values by the given factor.
func CopyAndScale(p *profile.Profile, factor float64) *profile.Profile {
	cloned := p.Copy()
	cloned.Scale(factor)
	return cloned
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:golang/github.com/google/pprof@v0.0.0-20210407192527-94a9f03dee38",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/google/pprof@v0.0.0-20210407192527-94a9f03dee38"
  ],
  "symbols": [
    "github.com/google/pprof/profile.Merge",
    "github.com/google/pprof/profile.Profile.CheckValid",
    "github.com/google/pprof/profile.Profile.Copy",
    "github.com/google/pprof/profile.Profile.Scale"
  ]
}

package main

import (
	"fmt"
	"os"

	"github.com/google/pprof/profile"
	"sample"
)

func main() {
	// Assertion 1: profile.Merge combines multiple profiles of identical structure by aggregating sample values
	p1 := sample.CreateProfile("handleRequest", "server.go", 20, 10, 100000000)
	p2 := sample.CreateProfile("handleRequest", "server.go", 20, 15, 150000000)

	merged, err := sample.MergeProfiles([]*profile.Profile{p1, p2})
	if err != nil {
		fmt.Fprintf(os.Stderr, "MergeProfiles failed: %v\n", err)
		os.Exit(1)
	}

	if err := merged.CheckValid(); err != nil {
		fmt.Fprintf(os.Stderr, "merged profile CheckValid failed: %v\n", err)
		os.Exit(1)
	}

	if len(merged.Sample) != 1 {
		fmt.Fprintf(os.Stderr, "expected 1 sample after merge, got %d\n", len(merged.Sample))
		os.Exit(1)
	}

	if merged.Sample[0].Value[0] != 25 || merged.Sample[0].Value[1] != 250000000 {
		fmt.Fprintf(os.Stderr, "merged sample values mismatch: got %v, expected [25, 250000000]\n", merged.Sample[0].Value)
		os.Exit(1)
	}

	// Assertion 2: profile.Profile.Copy creates an independent deep copy of the profile
	cloned := p1.Copy()
	if err := cloned.CheckValid(); err != nil {
		fmt.Fprintf(os.Stderr, "cloned profile CheckValid failed: %v\n", err)
		os.Exit(1)
	}
	if cloned.Sample[0].Value[0] != 10 {
		fmt.Fprintf(os.Stderr, "cloned profile value mismatch: got %d, expected 10\n", cloned.Sample[0].Value[0])
		os.Exit(1)
	}

	// Assertion 3: profile.Profile.Scale multiplies all sample values by a scaling factor
	scaled := sample.CopyAndScale(p1, 2.5)
	if scaled.Sample[0].Value[0] != 25 || scaled.Sample[0].Value[1] != 250000000 {
		fmt.Fprintf(os.Stderr, "scaled sample values mismatch: got %v, expected [25, 250000000]\n", scaled.Sample[0].Value)
		os.Exit(1)
	}
	// Original profile values must remain unchanged
	if p1.Sample[0].Value[0] != 10 || p1.Sample[0].Value[1] != 100000000 {
		fmt.Fprintf(os.Stderr, "original profile mutated after copy and scale\n")
		os.Exit(1)
	}

	fmt.Println("All pprof profile merge and scale contract assertions passed.")
}