test(agentcompat): add exact stress scenario

Co-authored-by: naiba/CloudCode <hi+cloudcode@nai.ba>

integration/agentcompat/internal/scenario/stress_path_lock.go

@@ -0,0 +1,73 @@
+//go:build linux && agentcompat
+
+package scenario
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strconv"
+	"strings"
+)
+
+var ErrStressPathLockProof = errors.New("stress path-lock proof is invalid")
+
+type stressPathLockProof struct {
+	Stripes int
+}
+
+func (proof stressPathLockProof) Validate() error {
+	if proof.Stripes != 1024 {
+		return fmt.Errorf("stripes=%d: %w", proof.Stripes, ErrStressPathLockProof)
+	}
+	return nil
+}
+
+func proveStressPathLockStripes(ctx context.Context, sourceDir string) (stressPathLockProof, error) {
+	if sourceDir == "" {
+		return stressPathLockProof{}, ErrStressPathLockProof
+	}
+	root, err := os.MkdirTemp("", "nezha-stress-path-lock-")
+	if err != nil {
+		return stressPathLockProof{}, err
+	}
+	defer os.RemoveAll(root)
+	probe := filepath.Join(root, "agentcompat_path_lock_proof_test.go")
+	content := "package main\n\nimport (\n\t\"fmt\"\n\t\"testing\"\n)\n\nconst agentCompatPathLockStripes = fsPathLockStripes\n\nvar _ [agentCompatPathLockStripes - 1024]struct{}\nvar _ [1024 - agentCompatPathLockStripes]struct{}\n\nfunc TestAgentCompatPathLockProof(t *testing.T) {\n\tfmt.Printf(\"AGENTCOMPAT_PATH_LOCK_STRIPES=%d\\n\", agentCompatPathLockStripes)\n}\n"
+	if err := os.WriteFile(probe, []byte(content), 0o600); err != nil {
+		return stressPathLockProof{}, err
+	}
+	overlayPath := filepath.Join(root, "overlay.json")
+	original := filepath.Join(sourceDir, "cmd", "agent", "mcp_fs_path_lock_bounded_test.go")
+	overlayData, err := json.Marshal(struct {
+		Replace map[string]string `json:"Replace"`
+	}{Replace: map[string]string{original: probe}})
+	if err != nil {
+		return stressPathLockProof{}, err
+	}
+	if err := os.WriteFile(overlayPath, overlayData, 0o600); err != nil {
+		return stressPathLockProof{}, err
+	}
+	command := exec.CommandContext(ctx, "go", "test", "-overlay", overlayPath, "./cmd/agent", "-run", "^TestAgentCompatPathLockProof$", "-count=1", "-v")
+	command.Dir = sourceDir
+	command.Env = append(os.Environ(), "GOFLAGS=")
+	output, err := command.CombinedOutput()
+	if err != nil {
+		return stressPathLockProof{}, fmt.Errorf("compile path-lock proof: %w: %s", err, output)
+	}
+	for _, line := range strings.Split(string(output), "\n") {
+		if !strings.HasPrefix(line, "AGENTCOMPAT_PATH_LOCK_STRIPES=") {
+			continue
+		}
+		value, parseErr := strconv.Atoi(strings.TrimPrefix(line, "AGENTCOMPAT_PATH_LOCK_STRIPES="))
+		if parseErr == nil {
+			proof := stressPathLockProof{Stripes: value}
+			return proof, proof.Validate()
+		}
+	}
+	return stressPathLockProof{}, fmt.Errorf("path-lock proof output missing: %w", ErrStressPathLockProof)
+}