fix(vfs): improve temp file deletion and level-1 position initialization

- Refactor Delete() error handling for clearer control flow
- Ignore ErrNotExist when removing temp files from disk
- Seed maxTXID1 during Open() based on restore plan for correct dual-polling
- Add tests for Open() position seeding and Delete() edge cases

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: corylanou

vfs.go

@@ -77,12 +77,13 @@ func (vfs *VFS) openMainDB(name string, flags sqlite3vfs.OpenFlag) (sqlite3vfs.F
 
 func (vfs *VFS) Delete(name string, dirSync bool) error {
 	slog.Info("deleting file", "name", name, "dirSync", dirSync)
-	if err := vfs.deleteTempFile(name); err == nil {
-		return nil
-	} else if !errors.Is(err, os.ErrNotExist) && !errors.Is(err, errTempFileNotFound) {
+	if err := vfs.deleteTempFile(name); err != nil {
+		if errors.Is(err, os.ErrNotExist) || errors.Is(err, errTempFileNotFound) {
+			return nil
+		}
 		return err
 	}
-	return fmt.Errorf("cannot delete vfs file")
+	return nil
 }
 
 func (vfs *VFS) Access(name string, flag sqlite3vfs.AccessFlag) (bool, error) {
@@ -176,7 +177,7 @@ func (vfs *VFS) deleteTempFile(name string) error {
 	if !ok {
 		return errTempFileNotFound
 	}
-	if err := os.Remove(path); err != nil {
+	if err := os.Remove(path); err != nil && !errors.Is(err, os.ErrNotExist) {
 		return err
 	}
 	vfs.tempFiles.Delete(vfs.canonicalTempName(name))
@@ -307,12 +308,24 @@ func (f *VFSFile) Open() error {
 	}
 	f.pageSize = pageSize
 
-	// Determine the current position based off the latest LTX file.
-	var pos ltx.Pos
+	// Determine the current position & level-1 polling point based on restore plan.
+	var (
+		pos      ltx.Pos
+		maxTXID1 ltx.TXID
+	)
+	for _, info := range infos {
+		if info.Level == 1 && info.MaxTXID > maxTXID1 {
+			maxTXID1 = info.MaxTXID
+		}
+	}
 	if len(infos) > 0 {
 		pos = ltx.Pos{TXID: infos[len(infos)-1].MaxTXID}
+		if maxTXID1 == 0 {
+			maxTXID1 = pos.TXID
+		}
 	}
 	f.pos = pos
+	f.maxTXID1 = maxTXID1
 
 	// Build the page index so we can lookup individual pages.
 	if err := f.buildIndex(f.ctx, infos); err != nil {

vfs_lock_test.go

@@ -332,6 +332,56 @@ func TestVFSFile_CorruptedPageIndexRecovery(t *testing.T) {
 	}
 }
 
+func TestVFSFile_OpenSeedsLevel1Position(t *testing.T) {
+	client := newMockReplicaClient()
+	snapshot := buildLTXFixture(t, 1, 's')
+	snapshot.info.Level = SnapshotLevel
+	client.addFixture(t, snapshot)
+	l1 := buildLTXFixture(t, 2, 'l')
+	l1.info.Level = 1
+	client.addFixture(t, l1)
+	l0 := buildLTXFixture(t, 3, 'z')
+	l0.info.Level = 0
+	client.addFixture(t, l0)
+
+	f := NewVFSFile(client, "seed-level1.db", slog.Default())
+	if err := f.Open(); err != nil {
+		t.Fatalf("open vfs file: %v", err)
+	}
+	defer f.Close()
+
+	if got, want := f.maxTXID1, l1.info.MaxTXID; got != want {
+		t.Fatalf("unexpected maxTXID1: got %s want %s", got, want)
+	}
+	if got, want := f.Pos().TXID, l0.info.MaxTXID; got != want {
+		t.Fatalf("unexpected pos after open: got %s want %s", got, want)
+	}
+}
+
+func TestVFSFile_OpenSeedsLevel1PositionFromPos(t *testing.T) {
+	client := newMockReplicaClient()
+	snapshot := buildLTXFixture(t, 1, 's')
+	snapshot.info.Level = SnapshotLevel
+	client.addFixture(t, snapshot)
+	l0 := buildLTXFixture(t, 2, '0')
+	l0.info.Level = 0
+	client.addFixture(t, l0)
+
+	f := NewVFSFile(client, "seed-default.db", slog.Default())
+	if err := f.Open(); err != nil {
+		t.Fatalf("open vfs file: %v", err)
+	}
+	defer f.Close()
+
+	pos := f.Pos().TXID
+	if pos == 0 {
+		t.Fatalf("expected non-zero position")
+	}
+	if got := f.maxTXID1; got != pos {
+		t.Fatalf("expected maxTXID1 to equal pos when no L1 files, got %s want %s", got, pos)
+	}
+}
+
 func TestVFSFile_HeaderForcesDeleteJournal(t *testing.T) {
 	client := newMockReplicaClient()
 	client.addFixture(t, buildLTXFixture(t, 1, 'h'))
@@ -568,6 +618,61 @@ func TestVFS_TempFileDeleteOnClose(t *testing.T) {
 	if _, ok := vfs.loadTempFilePath(name); ok {
 		t.Fatalf("temp file tracking entry should be cleared")
 	}
+	if err := vfs.Delete(name, false); err != nil {
+		t.Fatalf("delete should ignore missing temp files: %v", err)
+	}
+	if err := vfs.Delete(name, false); err != nil {
+		t.Fatalf("delete should ignore repeated temp deletes: %v", err)
+	}
+}
+
+func TestVFS_DeleteIgnoresMissingTempFiles(t *testing.T) {
+	vfs := NewVFS(nil, slog.Default())
+
+	t.Run("AlreadyRemovedEntry", func(t *testing.T) {
+		name := "already-removed.db"
+		flags := sqlite3vfs.OpenTempDB | sqlite3vfs.OpenReadWrite | sqlite3vfs.OpenCreate | sqlite3vfs.OpenDeleteOnClose
+
+		file, _, err := vfs.openTempFile(name, flags)
+		if err != nil {
+			t.Fatalf("open temp file: %v", err)
+		}
+		tf := file.(*localTempFile)
+		if err := tf.Close(); err != nil {
+			t.Fatalf("close temp file: %v", err)
+		}
+		if err := vfs.Delete(name, false); err != nil {
+			t.Fatalf("delete should ignore missing tracked entry: %v", err)
+		}
+	})
+
+	t.Run("MissingOnDisk", func(t *testing.T) {
+		name := "missing-on-disk.db"
+		flags := sqlite3vfs.OpenTempDB | sqlite3vfs.OpenReadWrite | sqlite3vfs.OpenCreate
+
+		file, _, err := vfs.openTempFile(name, flags)
+		if err != nil {
+			t.Fatalf("open temp file: %v", err)
+		}
+		tf := file.(*localTempFile)
+
+		path, ok := vfs.loadTempFilePath(name)
+		if !ok {
+			t.Fatalf("temp file not tracked")
+		}
+		if err := os.Remove(path); err != nil {
+			t.Fatalf("remove backing file: %v", err)
+		}
+		if err := vfs.Delete(name, false); err != nil {
+			t.Fatalf("delete should ignore missing file: %v", err)
+		}
+		if _, ok := vfs.loadTempFilePath(name); ok {
+			t.Fatalf("temp file tracking entry should be cleared")
+		}
+		if err := tf.Close(); err != nil {
+			t.Fatalf("close temp file: %v", err)
+		}
+	})
 }
 
 func TestVFS_TempDirExhaustion(t *testing.T) {