fix(rules): 收紧规则读写健壮性

internal/context/source_rules_test.go

@@ -70,7 +70,7 @@ func TestRenderRulesDocumentBlockIncludesTruncationMarker(t *testing.T) {
 		Content:   "trimmed",
 		Truncated: true,
 	})
-	if !strings.Contains(block, "[truncated to fit rule file limit]") {
+	if !strings.Contains(block, "[truncated to fit rules budget]") {
 		t.Fatalf("expected truncation marker, got %q", block)
 	}
 }

internal/context/sources_test.go

@@ -77,6 +77,42 @@ func TestRulesPromptSourceSectionsRendersRules(t *testing.T) {
 	}
 }
 
+func TestRulesPromptSourceSectionsReflectRuleFileUpdatesOnNextBuild(t *testing.T) {
+	root := t.TempDir()
+	baseDir := filepath.Join(t.TempDir(), ".neocode")
+	if err := os.MkdirAll(baseDir, 0o755); err != nil {
+		t.Fatalf("mkdir baseDir: %v", err)
+	}
+	if _, err := rules.WriteGlobalRule(context.Background(), baseDir, "global-v1"); err != nil {
+		t.Fatalf("WriteGlobalRule(v1) error = %v", err)
+	}
+
+	source := newRulesPromptSource(rules.NewLoader(baseDir))
+	buildInput := BuildInput{Metadata: Metadata{ProjectRoot: root, Workdir: root}}
+
+	firstSections, err := source.Sections(context.Background(), buildInput)
+	if err != nil {
+		t.Fatalf("Sections(first) error = %v", err)
+	}
+	firstPrompt := renderPromptSection(firstSections[0])
+	if !strings.Contains(firstPrompt, "global-v1") {
+		t.Fatalf("expected first prompt to include global-v1, got %q", firstPrompt)
+	}
+
+	if _, err := rules.WriteGlobalRule(context.Background(), baseDir, "global-v2"); err != nil {
+		t.Fatalf("WriteGlobalRule(v2) error = %v", err)
+	}
+
+	secondSections, err := source.Sections(context.Background(), buildInput)
+	if err != nil {
+		t.Fatalf("Sections(second) error = %v", err)
+	}
+	secondPrompt := renderPromptSection(secondSections[0])
+	if !strings.Contains(secondPrompt, "global-v2") || strings.Contains(secondPrompt, "global-v1") {
+		t.Fatalf("expected second prompt to reflect latest global rule, got %q", secondPrompt)
+	}
+}
+
 func TestCorePromptSourceSectionsHonorsCancellation(t *testing.T) {
 	t.Parallel()
 

internal/rules/loader.go

@@ -10,13 +10,14 @@ import (
 )
 
 const (
-	agentsFileName    = "AGENTS.md"
-	documentRuneLimit = 4000
-	defaultRulesDir   = ".neocode"
+	agentsFileName        = "AGENTS.md"
+	documentReadRuneLimit = 16000
+	snapshotRuneLimit     = 4000
+	defaultRulesDir       = ".neocode"
 )
 
-// DefaultTruncationNotice 是规则文件超出注入预算时附加的统一提示。
-const DefaultTruncationNotice = "\n[truncated to fit rule file limit]\n"
+// DefaultTruncationNotice 是规则内容超出注入预算时附加的统一提示。
+const DefaultTruncationNotice = "\n[truncated to fit rules budget]\n"
 
 // Document 表示单个规则文件的已加载内容快照。
 type Document struct {
@@ -62,10 +63,11 @@ func (l *fileLoader) Load(ctx context.Context, projectRoot string) (Snapshot, er
 		return Snapshot{}, err
 	}
 
-	return Snapshot{
+	snapshot := Snapshot{
 		GlobalAGENTS:  globalDoc,
 		ProjectAGENTS: projectDoc,
-	}, nil
+	}
+	return enforceSnapshotBudget(snapshot), nil
 }
 
 // loadProjectDocument 读取项目根下的 AGENTS.md 作为项目规则。
@@ -102,17 +104,61 @@ func resolveBaseDir(baseDir string) string {
 		return filepath.Clean(trimmed)
 	}
 
-	home := strings.TrimSpace(os.Getenv("HOME"))
-	if !filepath.IsAbs(home) {
-		var err error
-		home, err = os.UserHomeDir()
-		if err != nil || !filepath.IsAbs(strings.TrimSpace(home)) {
-			return ""
-		}
+	home, err := os.UserHomeDir()
+	if err != nil || !filepath.IsAbs(strings.TrimSpace(home)) {
+		return ""
 	}
 	return filepath.Join(home, defaultRulesDir)
 }
 
+// enforceSnapshotBudget 按项目规则优先级裁剪合并后的规则快照总预算。
+func enforceSnapshotBudget(snapshot Snapshot) Snapshot {
+	remaining := snapshotRuneLimit
+
+	snapshot.ProjectAGENTS, remaining = truncateDocumentToBudget(snapshot.ProjectAGENTS, remaining)
+	snapshot.GlobalAGENTS, remaining = truncateDocumentToBudget(snapshot.GlobalAGENTS, remaining)
+
+	return snapshot
+}
+
+// truncateDocumentToBudget 按剩余预算裁剪单个规则文档，并尽量保持 Markdown 结构闭合。
+func truncateDocumentToBudget(document Document, budget int) (Document, int) {
+	content := strings.TrimSpace(document.Content)
+	if content == "" {
+		document.Content = ""
+		return document, maxInt(budget, 0)
+	}
+
+	if budget <= 0 {
+		document.Content = ""
+		document.Truncated = true
+		return document, 0
+	}
+
+	trimmed, truncated := truncateRuleMarkdown(content, budget)
+	document.Content = trimmed
+	document.Truncated = document.Truncated || truncated
+	return document, maxInt(budget-runeCount(trimmed), 0)
+}
+
+// truncateRuleMarkdown 按 rune 数量裁剪规则文本，并在需要时补齐未闭合的代码块围栏。
+func truncateRuleMarkdown(input string, max int) (string, bool) {
+	trimmed, truncated := truncateRunes(strings.TrimSpace(input), max)
+	if !truncated {
+		return trimmed, false
+	}
+
+	trimmed = strings.TrimRight(trimmed, "\n")
+	if strings.Count(trimmed, "```")%2 == 1 {
+		if max > len([]rune("\n```")) {
+			trimmed, _ = truncateRunes(trimmed, max-len([]rune("\n```")))
+			trimmed = strings.TrimRight(trimmed, "\n")
+		}
+		trimmed += "\n```"
+	}
+	return trimmed, true
+}
+
 // truncateRunes 按 rune 数量裁剪文本，避免破坏 UTF-8 多字节字符。
 func truncateRunes(input string, max int) (string, bool) {
 	if max <= 0 {
@@ -130,3 +176,11 @@ func truncateRunes(input string, max int) (string, bool) {
 func runeCount(input string) int {
 	return utf8.RuneCountInString(input)
 }
+
+// maxInt 返回两个整数中的较大值，用于避免预算结果出现负数。
+func maxInt(a, b int) int {
+	if a > b {
+		return a
+	}
+	return b
+}

internal/rules/loader_test.go

@@ -66,7 +66,7 @@ func TestLoaderLoadTruncatesLongDocument(t *testing.T) {
 	if err := os.MkdirAll(baseDir, 0o755); err != nil {
 		t.Fatalf("mkdir baseDir: %v", err)
 	}
-	large := strings.Repeat("规", documentRuneLimit+12)
+	large := strings.Repeat("规", snapshotRuneLimit+12)
 	if err := os.WriteFile(filepath.Join(baseDir, agentsFileName), []byte(large), 0o644); err != nil {
 		t.Fatalf("write AGENTS.md: %v", err)
 	}
@@ -78,11 +78,40 @@ func TestLoaderLoadTruncatesLongDocument(t *testing.T) {
 	if !snapshot.GlobalAGENTS.Truncated {
 		t.Fatalf("expected truncated global document")
 	}
-	if runeCount(snapshot.GlobalAGENTS.Content) != documentRuneLimit {
+	if runeCount(snapshot.GlobalAGENTS.Content) != snapshotRuneLimit {
 		t.Fatalf("unexpected truncated length = %d", runeCount(snapshot.GlobalAGENTS.Content))
 	}
 }
 
+func TestLoaderLoadEnforcesCombinedRulesBudget(t *testing.T) {
+	baseDir := filepath.Join(t.TempDir(), ".neocode")
+	projectRoot := t.TempDir()
+	if err := os.MkdirAll(baseDir, 0o755); err != nil {
+		t.Fatalf("mkdir baseDir: %v", err)
+	}
+
+	projectContent := strings.Repeat("甲", snapshotRuneLimit-10)
+	globalContent := strings.Repeat("乙", 32)
+	if err := os.WriteFile(filepath.Join(projectRoot, agentsFileName), []byte(projectContent), 0o644); err != nil {
+		t.Fatalf("write project AGENTS.md: %v", err)
+	}
+	if err := os.WriteFile(filepath.Join(baseDir, agentsFileName), []byte(globalContent), 0o644); err != nil {
+		t.Fatalf("write global AGENTS.md: %v", err)
+	}
+
+	snapshot, err := NewLoader(baseDir).Load(context.Background(), projectRoot)
+	if err != nil {
+		t.Fatalf("Load() error = %v", err)
+	}
+	if !snapshot.GlobalAGENTS.Truncated {
+		t.Fatalf("expected global rules to be truncated by combined budget")
+	}
+	total := runeCount(snapshot.ProjectAGENTS.Content) + runeCount(snapshot.GlobalAGENTS.Content)
+	if total != snapshotRuneLimit {
+		t.Fatalf("combined rule length = %d, want %d", total, snapshotRuneLimit)
+	}
+}
+
 func TestLoaderLoadReturnsEmptySnapshotWhenFilesAreMissing(t *testing.T) {
 	baseDir := filepath.Join(t.TempDir(), ".neocode")
 	snapshot, err := NewLoader(baseDir).Load(context.Background(), t.TempDir())
@@ -156,6 +185,17 @@ func TestResolveBaseDirCleansExplicitBaseDir(t *testing.T) {
 	}
 }
 
+func TestTruncateRuleMarkdownClosesCodeFence(t *testing.T) {
+	input := "before\n```go\nfmt.Println(\"x\")\n"
+	got, truncated := truncateRuleMarkdown(input, len([]rune("before\n```go\nfmt.Pri")))
+	if !truncated {
+		t.Fatalf("expected truncated markdown")
+	}
+	if !strings.HasSuffix(got, "\n```") {
+		t.Fatalf("expected closing fence, got %q", got)
+	}
+}
+
 func TestTruncateRunesWithZeroBudget(t *testing.T) {
 	got, truncated := truncateRunes("规则", 0)
 	if got != "" || !truncated {

internal/rules/store.go

@@ -5,12 +5,20 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"runtime"
 	"strings"
+	"time"
 	"unicode/utf8"
 )
 
 const rulesFilePermission = 0o644
 
+var (
+	renameFile = os.Rename
+	removeFile = os.Remove
+	sleepFn    = time.Sleep
+)
+
 // GlobalRulePath 返回全局规则文件 AGENTS.md 的固定路径。
 func GlobalRulePath(baseDir string) string {
 	resolvedBaseDir := resolveBaseDir(baseDir)
@@ -103,8 +111,11 @@ func readRuleDocument(path string) (Document, error) {
 		}
 		return Document{}, fmt.Errorf("rules: read %s: %w", path, err)
 	}
+	if !utf8.Valid(data) {
+		return Document{}, fmt.Errorf("rules: read %s: content is not valid UTF-8", path)
+	}
 
-	content, truncated := truncateRunes(strings.TrimSpace(string(data)), documentRuneLimit)
+	content, truncated := truncateRunes(strings.TrimSpace(string(data)), documentReadRuneLimit)
 	return Document{
 		Path:      path,
 		Content:   content,
@@ -142,8 +153,36 @@ func writeRuleFile(path string, content string) error {
 	if err := os.Chmod(tempPath, rulesFilePermission); err != nil {
 		return fmt.Errorf("rules: chmod temp file for %s: %w", path, err)
 	}
-	if err := os.Rename(tempPath, path); err != nil {
-		return fmt.Errorf("rules: commit file %s: %w", path, err)
+	if err := commitWithRetry(tempPath, path, runtime.GOOS == "windows"); err != nil {
+		return err
 	}
 	return nil
 }
+
+// commitWithRetry 在最终提交规则文件时处理临时占用导致的瞬时失败。
+func commitWithRetry(tempPath, path string, allowReplace bool) error {
+	var last error
+	for attempt := 0; attempt < 5; attempt++ {
+		if err := renameWithReplace(tempPath, path, allowReplace); err == nil {
+			return nil
+		} else {
+			last = err
+		}
+		sleepFn(time.Duration(25*(1<<attempt)) * time.Millisecond)
+	}
+	return fmt.Errorf("rules: commit file %s: %w", path, last)
+}
+
+// renameWithReplace 在需要时先删除旧文件，再提交新的规则文件内容。
+func renameWithReplace(tempPath, path string, allowReplace bool) error {
+	if err := renameFile(tempPath, path); err == nil {
+		return nil
+	} else if !allowReplace {
+		return err
+	}
+
+	if err := removeFile(path); err != nil && !os.IsNotExist(err) {
+		return err
+	}
+	return renameFile(tempPath, path)
+}