diff --git a/devel/4453.md b/devel/4453.md
new file mode 100644
index 0000000000..1eeb222ed6
--- /dev/null
+++ b/devel/4453.md
@@ -0,0 +1,50 @@
+# 4453 带路径包名的 use-package 找不到 $TEXMACS_HOME_PATH 下的用户包
+
+## 背景
+
+用户包放在 `$TEXMACS_HOME_PATH/packages/TST-core/` 下，自己用
+`<use-package|TST-core/unicode/unicode-figures>` 级联加载子包。
+GNU TeXmacs 2.1.5 与 2026_2.6 正常，2026_3.2 起子包不再被加载，
+宏原样显示成 `⟨big-unicode-table|...⟩`。把三个包一起加进文档的
+style/package 列表则正常，只有包体里的级联失效。
+
+## 定位
+
+1200（`17e6bab45`）给 `exec_use_package` 加了带路径包名的直查快路径，
+包名含 `/` 时只查 `$TEXMACS_PATH/packages` 和
+`$TEXMACS_PATH/plugins/<首段>/packages`，不查 `$TEXMACS_HOME_PATH`。
+1200 之前是拿 `$TEXMACS_STYLE_PATH` 去 resolve，那个变量由
+`search_sub_dirs (style_root | package_root)` 生成，含
+`$TEXMACS_HOME_PATH/packages` 及其全部子目录，所以用户包能找到。
+
+手动加进文档包列表之所以正常：文档自己的列表先过 `preprocess_style`
+（`new_style.cpp:118`）解析成绝对路径再交给 `exec`，而
+`url::operator*` 遇到 rooted 右操作数直接返回右操作数
+（`lolly/System/Classes/url.cpp:645`），于是绝对路径仍能命中。
+包体里的相对名没有这一步兜底。
+
+## 改动
+
+`resolve_dotted_package` 改为接收 `base_file_name`，在
+`$TEXMACS_PACKAGE_ROOT`、`$TEXMACS_STYLE_ROOT`、文档所在目录
+（本地文档沿祖先目录上溯）里依次直查。两个根变量条目数是
+「2 + 插件个数」量级，不是递归展开全部子目录的 `$TEXMACS_STYLE_PATH`，
+1200 的性能优化基本保留；`plugin_path` 的 base 是
+`$TEXMACS_HOME_PATH:$TEXMACS_PATH`，已覆盖原来的插件规则。
+
+`resolve_pack_in` 增加 or-url 分支逐根遍历，让「`.stem` 优先 `.ts`」
+只在同一个根内生效，靠前的根（用户包）才能覆盖靠后的根（内置包）。
+
+定位一个内置包的 stat 次数：1200 之前 8 次，1200 为 1 次，现在 3 次。
+
+**涉及文件**：`src/Typeset/Env/env_exec.cpp`
+
+## 回归测试
+
+`tests/Typeset/Env/use_package_resolve_test.cpp`，在临时
+`$TEXMACS_HOME_PATH` 下铺出 issue 里的两层包结构，只 use-package
+入口包，断言子包的宏确实进了环境。另覆盖文档相对定位、
+home 插件目录、style 根、两个根的先后顺序、裸包名不回归、
+找不到的包不崩。改动前 4 passed / 5 failed，改动后 9 passed。
+
+**涉及文件**：`tests/Typeset/Env/use_package_resolve_test.cpp`
diff --git a/src/Typeset/Env/env_exec.cpp b/src/Typeset/Env/env_exec.cpp
index 8310a060ce..24f9c684f2 100644
--- a/src/Typeset/Env/env_exec.cpp
+++ b/src/Typeset/Env/env_exec.cpp
@@ -1208,13 +1208,19 @@ filter_style (tree t) {
 }
 
 /**
- * @brief 在指定根目录下按相对路径定位包文件，优先 .stem 后 .ts
- * @param root 包根目录
- * @param pi   带路径的包名（如 a/b/c），可显式带 .ts/.stem 后缀
- * @return 解析到的文件 url，未找到返回 url_none
+ * @brief 在根目录下定位包文件，优先 .stem 后 .ts
+ * @param root 包根目录，可以是 or-url，按先后顺序逐个尝试
+ * @param pi   带路径的包名，可显式带 .ts/.stem 后缀
  */
 static url
 resolve_pack_in (url root, string pi) {
+  // 逐根尝试而不是把 or-url 整个交给 resolve，让「.stem 优先 .ts」只在同一个
+  // 根内生效，靠前的根里的 .ts 才能覆盖靠后的根里的同名 .stem
+  if (is_or (root)) {
+    url name= resolve_pack_in (root[1], pi);
+    if (!is_none (name)) return name;
+    return resolve_pack_in (root[2], pi);
+  }
   if (ends (pi, ".ts") || ends (pi, ".stem")) return resolve (root * pi);
   url name= resolve (root * (pi * string (".stem")));
   if (is_none (name)) name= resolve (root * (pi * string (".ts")));
@@ -1222,18 +1228,26 @@ resolve_pack_in (url root, string pi) {
 }
 
 /**
- * @brief 带路径包名（含 /）的直查解析，避免 resolve 对 $TEXMACS_STYLE_PATH
- * 全部子目录逐一扫描
- * @note 依次尝试 $TEXMACS_PATH/packages 与
- * $TEXMACS_PATH/plugins/<首段>/packages
+ * @brief 带路径包名的搜索根：package 根、style 根、文档所在目录
+ * @note 两个根变量由 init_env_vars 设置，条目数是「2 + 插件个数」量级，
+ * 不是 $TEXMACS_STYLE_PATH 那种递归展开出全部子目录的路径
+ */
+static url
+package_search_roots (url base_file_name) {
+  url roots= url ("$TEXMACS_PACKAGE_ROOT") | url ("$TEXMACS_STYLE_ROOT");
+  if (is_none (base_file_name)) return roots;
+  // 本地文档沿祖先目录上溯，与不带路径包名的分支一致
+  if (is_rooted (base_file_name, "default"))
+    return roots | ::expand (head (base_file_name) * url_ancestor ());
+  return roots | head (base_file_name);
+}
+
+/**
+ * @brief 带路径包名（含 /）的直查解析，避免逐一扫描 $TEXMACS_STYLE_PATH
  */
 static url
-resolve_dotted_package (string pi) {
-  url name= resolve_pack_in (url ("$TEXMACS_PATH/packages"), pi);
-  if (!is_none (name)) return name;
-  int pos= search_forwards ("/", 0, pi);
-  return resolve_pack_in (
-      url ("$TEXMACS_PATH/plugins") * pi (0, pos) * "packages", pi);
+resolve_dotted_package (string pi, url base_file_name) {
+  return resolve_pack_in (package_search_roots (base_file_name), pi);
 }
 
 tree
@@ -1245,7 +1259,7 @@ edit_env_rep::exec_use_package (tree t) {
     string pi  = as_string (t[i]);
     string task= "use-package " * pi;
     bench_start (task);
-    if (occurs ("/", pi)) name= resolve_dotted_package (pi);
+    if (occurs ("/", pi)) name= resolve_dotted_package (pi, base_file_name);
     else {
       if (is_rooted (base_file_name, "default"))
         styp= styp | ::expand (head (base_file_name) * url_ancestor ());
diff --git a/tests/Typeset/Env/use_package_resolve_test.cpp b/tests/Typeset/Env/use_package_resolve_test.cpp
new file mode 100644
index 0000000000..571056e520
--- /dev/null
+++ b/tests/Typeset/Env/use_package_resolve_test.cpp
@@ -0,0 +1,221 @@
+/******************************************************************************
+ * MODULE     : use_package_resolve_test.cpp
+ * DESCRIPTION: 带路径包名 <use-package|a/b/c> 的解析回归测试
+ * COPYRIGHT  : (C) 2026  Darcy Shen
+ *******************************************************************************
+ * This software falls under the GNU general public license version 3 or later.
+ * It comes WITHOUT ANY WARRANTY WHATSOEVER. For details, see the file LICENSE
+ * in the root directory or <http://www.gnu.org/licenses/gpl-3.0.html>.
+ ******************************************************************************/
+
+#include "Metafont/load_tex.hpp"
+#include "base.hpp"
+#include "data_cache.hpp"
+#include "env.hpp"
+#include "file.hpp"
+#include "sys_utils.hpp"
+#include "tm_sys_utils.hpp"
+#include <QtTest/QtTest>
+#include <moebius/drd/drd_std.hpp>
+#include <moebius/tree_label.hpp>
+
+using namespace moebius; // USE_PACKAGE
+using moebius::drd::init_std_drd;
+using moebius::drd::std_drd;
+
+// edit_env 按引用持有 drd 和各 hashmap，必须与 env 同生命周期
+struct test_env {
+  drd_info              drd;
+  hashmap<string, tree> lref, gref, laux, gaux, latt, gatt;
+  edit_env              env;
+
+  test_env (url base_file_name)
+      : drd ("test", std_drd),
+        env (drd, base_file_name, lref, gref, laux, gaux, latt, gatt) {}
+};
+
+static url the_home= url_none ();
+static url the_doc = url_none ();
+
+static void
+write_pack (url file, string body) {
+  make_dir (head (file));
+  string doc= string ("<TeXmacs|2.1.5>\n\n<style|source>\n\n<\\body>\n  ") *
+              body * string ("\n</body>\n");
+  QVERIFY (!save_string (file, doc, false));
+}
+
+static void
+set_roots (url package_root, url style_root) {
+  set_env ("TEXMACS_PACKAGE_ROOT", as_string (package_root));
+  set_env ("TEXMACS_STYLE_ROOT", as_string (style_root));
+}
+
+class TestUsePackageResolve : public QObject {
+  Q_OBJECT
+
+private slots:
+  void initTestCase ();
+  void init ();
+  void cleanupTestCase ();
+
+  void nested_user_package ();
+  void document_relative_package ();
+  void home_plugin_package ();
+  void style_root_package ();
+  void package_root_wins_over_style_root ();
+  void bare_package_name_still_works ();
+  void missing_package_is_silent ();
+};
+
+void
+TestUsePackageResolve::initTestCase () {
+  // edit_env 的构造会走到 update_font，字体栈没起来会抛异常，
+  // 所以先初始化 TeX/字体环境，之后再改写 TEXMACS_HOME_PATH
+  init_lolly ();
+  init_texmacs_home_path ();
+  cache_initialize ();
+  init_tex ();
+  init_std_drd ();
+
+  the_home= url_temp ();
+  the_doc = url_temp ();
+
+  // issue #4453 复现用的用户包：入口包在 TST-core/，两个子包在
+  // TST-core/unicode/
+  url packages= the_home * "packages";
+  write_pack (packages * "TST-core" * "unicode" * "unicode-figures.ts",
+              "<assign|unicode-figures-marker|<macro|figures>>");
+  write_pack (packages * "TST-core" * "unicode" * "unicode-environments.ts",
+              "<assign|unicode-environments-marker|<macro|environments>>");
+  write_pack (packages * "TST-core" * "unicode-core.ts",
+              "<use-package|TST-core/unicode/unicode-figures>\n"
+              "  <use-package|TST-core/unicode/unicode-environments>\n"
+              "  <assign|unicode-core-marker|<macro|core>>");
+
+  // 不带路径的包名，走未改动的 $TEXMACS_STYLE_PATH 分支
+  write_pack (packages * "solo.ts", "<assign|solo-marker|<macro|solo>>");
+
+  // package 根与 style 根同名同路径，用于验证根的先后顺序
+  write_pack (packages * "over" * "pack.ts",
+              "<assign|over-from-packages|<macro|packages>>");
+  write_pack (the_home * "styles" * "over" * "pack.ts",
+              "<assign|over-from-styles|<macro|styles>>");
+  write_pack (the_home * "styles" * "TST-style" * "style-pack.ts",
+              "<assign|style-pack-marker|<macro|style>>");
+
+  // $TEXMACS_HOME_PATH 下的插件包
+  write_pack (the_home * "plugins" * "tstplug" * "packages" * "tstplug" *
+                  "deep" * "plug-pack.ts",
+              "<assign|plug-pack-marker|<macro|plug>>");
+
+  // 文档旁边的包，文档本身放在下一层，同时覆盖祖先目录上溯
+  write_pack (the_doc * "relative" * "rel-pack.ts",
+              "<assign|rel-pack-marker|<macro|rel>>");
+
+  set_env ("TEXMACS_HOME_PATH", as_string (the_home));
+}
+
+void
+TestUsePackageResolve::init () {
+  // 每个用例自己声明搜索根，避免相互影响
+  set_env ("TEXMACS_PACKAGE_ROOT", "");
+  set_env ("TEXMACS_STYLE_ROOT", "");
+  set_env ("TEXMACS_STYLE_PATH", "");
+}
+
+void
+TestUsePackageResolve::cleanupTestCase () {
+  if (!is_none (the_home)) rmdir (the_home);
+  if (!is_none (the_doc)) rmdir (the_doc);
+}
+
+// issue #4453：只加 unicode-core，两个子包必须级联加载
+void
+TestUsePackageResolve::nested_user_package () {
+  set_roots (url ("$TEXMACS_HOME_PATH/packages"),
+             url ("$TEXMACS_HOME_PATH/styles"));
+
+  test_env te (url ("$PWD/none"));
+  te.env->exec (tree (USE_PACKAGE, string ("TST-core/unicode-core")));
+
+  QVERIFY (te.env->provides ("unicode-core-marker"));
+  QVERIFY (te.env->provides ("unicode-figures-marker"));
+  QVERIFY (te.env->provides ("unicode-environments-marker"));
+}
+
+// 文档在 <doc>/sub/，包在 <doc>/relative/，靠祖先目录上溯找到
+void
+TestUsePackageResolve::document_relative_package () {
+  set_roots (url ("$TEXMACS_HOME_PATH/packages"),
+             url ("$TEXMACS_HOME_PATH/styles"));
+
+  test_env te (the_doc * "sub" * "doc.tm");
+  te.env->exec (tree (USE_PACKAGE, string ("relative/rel-pack")));
+
+  QVERIFY (te.env->provides ("rel-pack-marker"));
+}
+
+// $TEXMACS_HOME_PATH/plugins/<插件>/packages 下的包
+void
+TestUsePackageResolve::home_plugin_package () {
+  set_roots (url ("$TEXMACS_HOME_PATH/packages") |
+                 url ("$TEXMACS_HOME_PATH/plugins/tstplug/packages"),
+             url ("$TEXMACS_HOME_PATH/styles"));
+
+  test_env te (url ("$PWD/none"));
+  te.env->exec (tree (USE_PACKAGE, string ("tstplug/deep/plug-pack")));
+
+  QVERIFY (te.env->provides ("plug-pack-marker"));
+}
+
+// 带路径包名也要能落到 style 根上
+void
+TestUsePackageResolve::style_root_package () {
+  set_roots (url ("$TEXMACS_HOME_PATH/packages"),
+             url ("$TEXMACS_HOME_PATH/styles"));
+
+  test_env te (url ("$PWD/none"));
+  te.env->exec (tree (USE_PACKAGE, string ("TST-style/style-pack")));
+
+  QVERIFY (te.env->provides ("style-pack-marker"));
+}
+
+// 同名包同时在两个根里时，靠前的根胜出
+void
+TestUsePackageResolve::package_root_wins_over_style_root () {
+  set_roots (url ("$TEXMACS_HOME_PATH/packages"),
+             url ("$TEXMACS_HOME_PATH/styles"));
+
+  test_env te (url ("$PWD/none"));
+  te.env->exec (tree (USE_PACKAGE, string ("over/pack")));
+
+  QVERIFY (te.env->provides ("over-from-packages"));
+  QVERIFY (!te.env->provides ("over-from-styles"));
+}
+
+// 不含 / 的包名仍走 $TEXMACS_STYLE_PATH，防回归
+void
+TestUsePackageResolve::bare_package_name_still_works () {
+  set_env ("TEXMACS_STYLE_PATH", as_string (the_home * "packages"));
+
+  test_env te (url ("$PWD/none"));
+  te.env->exec (tree (USE_PACKAGE, string ("solo")));
+
+  QVERIFY (te.env->provides ("solo-marker"));
+}
+
+// 找不到的包不崩、不定义任何东西
+void
+TestUsePackageResolve::missing_package_is_silent () {
+  set_roots (url ("$TEXMACS_HOME_PATH/packages"),
+             url ("$TEXMACS_HOME_PATH/styles"));
+
+  test_env te (url ("$PWD/none"));
+  te.env->exec (tree (USE_PACKAGE, string ("no/such/package")));
+
+  QVERIFY (!te.env->provides ("unicode-figures-marker"));
+}
+
+QTEST_MAIN (TestUsePackageResolve)
+#include "use_package_resolve_test.moc"