github.com/go-stack/stack v1.8.0: CallStack.TrimRuntime

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-stack/stack@v1.8.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/go-stack/stack@v1.8.0
Demonstrate these symbols/APIs:
  - stack.CallStack.TrimRuntime

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.

package sample

import (
	"strings"
	"testing"

	"github.com/go-stack/stack"
)

func helperFunction() (stack.CallStack, stack.CallStack) {
	raw := stack.Trace()
	trimmed := raw.TrimRuntime()
	return raw, trimmed
}

func TestTrimRuntimeRemovesRuntimeFrames(t *testing.T) {
	raw, trimmed := helperFunction()
	if len(raw) == 0 {
		t.Fatalf("expected non-empty raw stack trace")
	}
	if len(trimmed) >= len(raw) {
		t.Fatalf("expected trimmed stack length (%d) to be strictly less than raw length (%d)", len(trimmed), len(raw))
	}

	// Verify the removed frames at the tail of raw originate from GOROOT / runtime
	removed := raw[len(trimmed):]
	if len(removed) == 0 {
		t.Fatalf("expected at least one runtime frame to be trimmed")
	}
	for i, frame := range removed {
		fn := frame.Frame().Function
		file := frame.Frame().File
		isRuntimeOrStd := strings.Contains(file, "/src/") ||
			strings.HasSuffix(file, "_testmain.go") ||
			strings.HasPrefix(fn, "runtime.") ||
			strings.HasPrefix(fn, "testing.")
		if !isRuntimeOrStd {
			t.Fatalf("frame %d (%s at %s) was trimmed but does not appear to be a runtime/GOROOT frame", i, fn, file)
		}
	}
}

func TestTrimRuntimePreservesApplicationFrames(t *testing.T) {
	appStack := CaptureApplicationStack()
	if len(appStack) < 2 {
		t.Fatalf("expected at least 2 application frames, got %d", len(appStack))
	}

	f0 := appStack[0].Frame()
	if !strings.HasSuffix(f0.Function, "CaptureApplicationStack") {
		t.Fatalf("expected frame 0 to be CaptureApplicationStack, got %s", f0.Function)
	}

	f1 := appStack[1].Frame()
	if !strings.HasSuffix(f1.Function, "TestTrimRuntimePreservesApplicationFrames") {
		t.Fatalf("expected frame 1 to be TestTrimRuntimePreservesApplicationFrames, got %s", f1.Function)
	}

	for i, frame := range appStack {
		fn := frame.Frame().Function
		if strings.HasPrefix(fn, "runtime.") || strings.HasPrefix(fn, "testing.") {
			t.Fatalf("retained frame %d is runtime/testing function: %s", i, fn)
		}
	}
}

func TestTrimRuntimeAllRuntimeFrames(t *testing.T) {
	raw := stack.Trace()
	runtimeOnly := raw[len(raw.TrimRuntime()):]
	if len(runtimeOnly) == 0 {
		t.Fatalf("expected non-empty runtime-only slice")
	}

	trimmed := TrimStackRuntime(runtimeOnly)
	if len(trimmed) != 0 {
		t.Fatalf("expected empty CallStack when trimming runtime-only frames, got length %d", len(trimmed))
	}
}

{"case":{"caseId":"case:sha256:0021e7c2769db6ea0d247f160c43a4ef2b33a6bd327ae6a73a1566cdd0a35f9f","contract":["stack.CallStack.TrimRuntime removes Go runtime frames from the end of a captured CallStack","stack.CallStack.TrimRuntime preserves application function calls in the stack trace","stack.CallStack.TrimRuntime produces an empty stack when all frames belong to the runtime"],"goal":"verify pkg:golang/github.com/go-stack/stack@v1.8.0","kind":"HOW","packages":["pkg:golang/github.com/go-stack/stack@v1.8.0"],"schemaVersion":1,"symbols":["stack.CallStack.TrimRuntime"]},"contractCommand":["go","test","./..."],"environment":{"arch":"amd64","compiler":"go","compilerVersion":"1.26.6","distro":"ubuntu","ecosystem":"golang","language":"go","languageVersion":"1.26.6","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","packageManagerVersion":"1.26.6","runtime":"go","runtimeVersion":"1.26.6","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/github.com/go-stack/stack@v1.8.0"],"schemaVersion":1,"subject":"pkg:golang/github.com/go-stack/stack@v1.8.0","symbols":["stack.CallStack.TrimRuntime"],"verifierAdapter":"golang@1"}

module example.com/sample

go 1.26.6

require github.com/go-stack/stack v1.8.0

github.com/go-stack/stack v1.8.0 h1:5SgMzNM5HxrEjV0ww2lTmX6E2Izsfxas4+YHWRs3Lsk=
github.com/go-stack/stack v1.8.0/go.mod h1:v0f6uXyyMGvRgIKkXu+yp6POWl0qKG85gN/melR3HDY=

package sample

import (
	"github.com/go-stack/stack"
)

// CaptureApplicationStack captures the current call stack and trims trailing Go runtime frames.
func CaptureApplicationStack() stack.CallStack {
	trace := stack.Trace()
	return trace.TrimRuntime()
}

// TrimStackRuntime trims trailing Go runtime frames from a provided CallStack.
func TrimStackRuntime(cs stack.CallStack) stack.CallStack {
	return cs.TrimRuntime()
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:golang/github.com/go-stack/stack@v1.8.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/go-stack/stack@v1.8.0"
  ],
  "symbols": [
    "stack.CallStack.TrimRuntime"
  ]
}