LaTeX export fails silently if there exists an empty macro in the preamble

[ProfFan]

Mogan 版本

1.2.3-rc4

操作系统版本和架构

macOS Sonoma 14.2.1

描述问题

LaTeX 导出会失败但是没有报错

;string->symbol argument, "", is a string but should be a non-null string
;    ("Is @x a list with first stree @f?...
;    /Applications/MoganResearch.app/Contents/Resources/share/Xmacs/progs/kernel/library/base.scm, line 270, position: 9184
; collect-user-defs-sub: ("Is @x a list wit...
; collect-user-defs-sub: (((user-definition... ; t: (assign "" (macro ""))
;                                              tmtex-user-defs-table: (hash-table)
; collect-user-defs: ((ahash-set->list tmte...
; (map as-string (collect-user-defs st))     ; st: (document (hide-preamble (docum...

原因是我文档的 preamble 里面有一个空的 definition

奇怪的是 TeXmacs 原版没有问题

期待的结果

导出成功

[da-liii]

提供一下复现这个问题的文档。我用这个空的definition并没有复现这个问题