[dylink] Normalize library paths to prevent duplicate loading

When a shared library in a subdirectory references a dependency via
$ORIGIN/.. rpath, findLibraryFS resolves it to a non-canonical path
containing ".." (e.g. "sub/../lib.so"). Since loadDynamicLibrary uses
the raw path as the LDSO key, this causes the same library to be loaded
twice under different names, running constructors twice.

Fix by normalizing libName with PATH.normalize() at the top of
loadDynamicLibrary, matching what dlopenInternal already does.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: pepijndevos

src/lib/libdylink.js

@@ -1103,6 +1103,8 @@ var LibraryDylink = {
      * @param {Object=} localScope
      */`,
   $loadDynamicLibrary: function(libName, flags = {global: true, nodelete: true}, localScope, handle) {
+    // Avoid duplicate LDSO entries from non-canonical paths (e.g. "sub/../lib.so")
+    libName = PATH.normalize(libName);
 #if DYLINK_DEBUG
     dbg(`loadDynamicLibrary: ${libName} handle: ${handle}`);
     dbg('existing:', Object.keys(LDSO.loadedLibsByName));

test/test_other.py

@@ -6884,6 +6884,60 @@ def _build(rpath_flag, expected, **kwds):
     # case 2) with rpath: success
     _build(['-Wl,-rpath,$ORIGIN/subdir,-rpath,$ORIGIN'], "Hello\nHello_dep\nHello_nested_dep\nOk\n")
 
+  @also_with_wasmfs
+  def test_dlopen_rpath_no_duplicate_load(self):
+    # Test that a library loaded both directly and as a transitive dependency
+    # via $ORIGIN/.. rpath is not loaded twice. Without path normalization in
+    # loadDynamicLibrary, the LDSO would contain both "/usr/lib/libbase.so"
+    # and "/usr/lib/subdir/../libbase.so" as separate entries.
+    create_file('libbase.cpp', r'''
+    #include <stdio.h>
+    static int init_count = 0;
+    struct Init { Init() { init_count++; } };
+    static Init init;
+    extern "C" {
+      int base_func() { return 42; }
+      int get_init_count() { return init_count; }
+    }
+    ''')
+    create_file('libplugin.c', r'''
+    extern int base_func();
+    int plugin_func() { return base_func() + 1; }
+    ''')
+    create_file('main.c', r'''
+    #include <assert.h>
+    #include <stdio.h>
+    #include <dlfcn.h>
+
+    int main() {
+      void *hbase = dlopen("/usr/lib/libbase.so", RTLD_NOW | RTLD_GLOBAL);
+      assert(hbase);
+
+      void *hplugin = dlopen("/usr/lib/subdir/libplugin.so", RTLD_NOW);
+      assert(hplugin);
+
+      int (*base_func)() = dlsym(hbase, "base_func");
+      int (*plugin_func)() = dlsym(hplugin, "plugin_func");
+      int (*get_init_count)() = dlsym(hbase, "get_init_count");
+
+      printf("base: %d\n", base_func());
+      printf("plugin: %d\n", plugin_func());
+      printf("init_count: %d\n", get_init_count());
+
+      dlclose(hplugin);
+      dlclose(hbase);
+      return 0;
+    }
+    ''')
+    os.mkdir('subdir')
+    self.run_process([EMCC, '-o', 'libbase.so', 'libbase.cpp', '-sSIDE_MODULE'])
+    self.run_process([EMCC, '-o', 'subdir/libplugin.so', 'libplugin.c', '-sSIDE_MODULE', './libbase.so', '-Wl,-rpath,$ORIGIN/..'])
+    self.do_runf('main.c', 'base: 42\nplugin: 43\ninit_count: 1\n',
+                 cflags=['--profiling-funcs', '-sMAIN_MODULE=2', '-sINITIAL_MEMORY=32Mb',
+                         '--embed-file', 'libbase.so@/usr/lib/libbase.so',
+                         '--embed-file', 'subdir/libplugin.so@/usr/lib/subdir/libplugin.so',
+                         '-L.', '-lbase', '-L./subdir', '-lplugin', '-sNO_AUTOLOAD_DYLIBS'])
+
   def test_dlopen_bad_flags(self):
     create_file('main.c', r'''
 #include <dlfcn.h>