fix: clean up failed pprof startup files

internal/pprof/pprof.go

@@ -7,7 +7,7 @@ import (
 	"os"
 	"path/filepath"
 	"runtime"
-	"runtime/pprof"
+	runtimepprof "runtime/pprof"
 	"sync"
 	"time"
 )
@@ -19,6 +19,9 @@ type ProfileSession struct {
 	logWriter   io.Writer
 }
 
+// startCPUProfile is a test seam for simulating runtime/pprof startup failures.
+var startCPUProfile = runtimepprof.StartCPUProfile
+
 // BeginProfiling starts CPU and memory profiling, writing the profiles to the specified directory.
 func BeginProfiling(profileDir string, logWriter io.Writer) *ProfileSession {
 	if err := os.MkdirAll(profileDir, 0o755); err != nil {
@@ -34,7 +37,9 @@ func BeginProfiling(profileDir string, logWriter io.Writer) *ProfileSession {
 		panic(err)
 	}
 
-	if err := pprof.StartCPUProfile(cpuFile); err != nil {
+	if err := startCPUProfile(cpuFile); err != nil {
+		cpuFile.Close()
+		os.Remove(cpuProfilePath)
 		panic(err)
 	}
 
@@ -47,15 +52,15 @@ func BeginProfiling(profileDir string, logWriter io.Writer) *ProfileSession {
 }
 
 func (p *ProfileSession) Stop() {
-	pprof.StopCPUProfile()
+	runtimepprof.StopCPUProfile()
 	p.cpuFile.Close()
 
 	if p.memFilePath != "" {
 		memFile, err := os.Create(p.memFilePath)
 		if err != nil {
 			panic(err)
 		}
-		if err := pprof.Lookup("allocs").WriteTo(memFile, 0); err != nil {
+		if err := runtimepprof.Lookup("allocs").WriteTo(memFile, 0); err != nil {
 			panic(err)
 		}
 		memFile.Close()
@@ -90,7 +95,7 @@ func (c *CPUProfiler) StartCPUProfile(profileDir string) error {
 		return fmt.Errorf("failed to create CPU profile file: %w", err)
 	}
 
-	if err := pprof.StartCPUProfile(cpuFile); err != nil {
+	if err := startCPUProfile(cpuFile); err != nil {
 		cpuFile.Close()
 		os.Remove(cpuProfilePath)
 		return fmt.Errorf("failed to start CPU profile: %w", err)
@@ -134,7 +139,7 @@ func SaveHeapProfile(profileDir string) (string, error) {
 	defer heapFile.Close()
 
 	runtime.GC()
-	if err := pprof.Lookup("heap").WriteTo(heapFile, 0); err != nil {
+	if err := runtimepprof.Lookup("heap").WriteTo(heapFile, 0); err != nil {
 		os.Remove(heapProfilePath)
 		return "", fmt.Errorf("failed to write heap profile: %w", err)
 	}
@@ -155,7 +160,7 @@ func SaveAllocProfile(profileDir string) (string, error) {
 	}
 	defer allocFile.Close()
 
-	if err := pprof.Lookup("allocs").WriteTo(allocFile, 0); err != nil {
+	if err := runtimepprof.Lookup("allocs").WriteTo(allocFile, 0); err != nil {
 		os.Remove(allocProfilePath)
 		return "", fmt.Errorf("failed to write alloc profile: %w", err)
 	}

internal/pprof/pprof_test.go

@@ -0,0 +1,34 @@
+package pprof
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/microsoft/typescript-go/internal/testutil"
+	"gotest.tools/v3/assert"
+)
+
+func TestBeginProfilingCleansUpCPUFileWhenStartFails(t *testing.T) {
+	wantErr := errors.New("failed to start profile")
+	originalStartCPUProfile := startCPUProfile
+	startCPUProfile = func(io.Writer) error {
+		return wantErr
+	}
+	t.Cleanup(func() {
+		startCPUProfile = originalStartCPUProfile
+	})
+
+	profileDir := t.TempDir()
+	cpuProfilePath := filepath.Join(profileDir, fmt.Sprintf("%d-cpuprofile.pb.gz", os.Getpid()))
+
+	testutil.AssertPanics(t, func() {
+		BeginProfiling(profileDir, io.Discard)
+	}, wantErr)
+
+	_, err := os.Stat(cpuProfilePath)
+	assert.Assert(t, os.IsNotExist(err), "expected CPU profile file to be removed after start failure, got %v", err)
+}