fix(markdown): prune stale exported files

SPEC.md

@@ -112,6 +112,9 @@ separators and unsafe punctuation with dashes:
 pages/<space-slug>/<page-title>-<short-id>.md
 ```
 
+Each export removes stale generated `.md` files under the Markdown root while
+leaving non-Markdown sidecar files alone.
+
 Each file starts with YAML-ish front matter:
 
 ```yaml

internal/markdown/export.go

@@ -2,11 +2,13 @@ package markdown
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"os"
 	"path/filepath"
 	"sort"
 	"strings"
+	"syscall"
 	"time"
 
 	"github.com/vincentkoc/notcrawl/internal/notiontext"
@@ -38,14 +40,19 @@ func (e Exporter) Export(ctx context.Context) (Summary, error) {
 		return Summary{}, err
 	}
 	var s Summary
+	keep := map[string]bool{}
 	for _, page := range pages {
 		path, err := e.writePage(ctx, page)
 		if err != nil {
 			return s, err
 		}
+		keep[filepath.Clean(path)] = true
 		s.Pages++
 		s.Files = append(s.Files, path)
 	}
+	if err := pruneStaleMarkdown(e.Dir, keep); err != nil {
+		return s, err
+	}
 	return s, nil
 }
 
@@ -211,6 +218,41 @@ func fallback(s, fallback string) string {
 	return fallback
 }
 
+func pruneStaleMarkdown(root string, keep map[string]bool) error {
+	var dirs []string
+	if err := filepath.WalkDir(root, func(path string, d os.DirEntry, err error) error {
+		if err != nil {
+			return err
+		}
+		path = filepath.Clean(path)
+		if d.IsDir() {
+			if path != filepath.Clean(root) {
+				dirs = append(dirs, path)
+			}
+			return nil
+		}
+		if filepath.Ext(path) == ".md" && !keep[path] {
+			return os.Remove(path)
+		}
+		return nil
+	}); err != nil {
+		return err
+	}
+	sort.Slice(dirs, func(i, j int) bool {
+		return len(dirs[i]) > len(dirs[j])
+	})
+	for _, dir := range dirs {
+		if err := os.Remove(dir); err != nil && !isIgnorableRemoveDirError(err) {
+			return err
+		}
+	}
+	return nil
+}
+
+func isIgnorableRemoveDirError(err error) bool {
+	return errors.Is(err, os.ErrNotExist) || errors.Is(err, syscall.ENOTEMPTY) || errors.Is(err, syscall.EEXIST)
+}
+
 func formatMS(ms int64) string {
 	if ms <= 0 {
 		return ""

internal/markdown/export_test.go

@@ -104,3 +104,40 @@ func TestExporterPreservesUnicodePathNames(t *testing.T) {
 		t.Fatalf("unexpected export path: %+v, want %s", s.Files, want)
 	}
 }
+
+func TestExporterPrunesStaleMarkdown(t *testing.T) {
+	ctx := context.Background()
+	st, err := store.Open(filepath.Join(t.TempDir(), "notcrawl.db"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer st.Close()
+	now := store.NowMS()
+	if err := st.UpsertPage(ctx, store.Page{ID: "page1", Title: "Launch", Alive: true, Source: "test", SyncedAt: now}); err != nil {
+		t.Fatal(err)
+	}
+
+	dir := t.TempDir()
+	staleDir := filepath.Join(dir, "old")
+	if err := os.MkdirAll(staleDir, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	staleMarkdown := filepath.Join(staleDir, "stale.md")
+	if err := os.WriteFile(staleMarkdown, []byte("old"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	keepNote := filepath.Join(staleDir, "note.txt")
+	if err := os.WriteFile(keepNote, []byte("keep"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	if _, err := (Exporter{Store: st, Dir: dir}).Export(ctx); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := os.Stat(staleMarkdown); !os.IsNotExist(err) {
+		t.Fatalf("expected stale markdown to be removed, stat err=%v", err)
+	}
+	if _, err := os.Stat(keepNote); err != nil {
+		t.Fatalf("expected non-markdown file to remain: %v", err)
+	}
+}