gnu: nautilus: Fix crash due to loading extensions twice.

Fixes <https://issues.guix.gnu.org/58221>.
Reported by Tobias Kortkamp <tobias.kortkamp@gmail.com>.

Previously, if NAUTILUS_EXTENSION_PATH contained the same directory
several times, Nautilus could end up loading the same extension a second
time and crash.  This patch ensures that each extension cannot be loaded
more than once.

* gnu/packages/patches/nautilus-extension-search-path.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.
* gnu/packages/gnome.scm (nautilus)[source]: Use it.
[arguments]: Remove 'make-extensible' phase.

gnu/local.mk

@@ -1561,6 +1561,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/musl-cross-locale.patch			\
   %D%/packages/patches/mutt-store-references.patch		\
   %D%/packages/patches/m4-gnulib-libio.patch			\
+  %D%/packages/patches/nautilus-extension-search-path.patch	\
   %D%/packages/patches/ncompress-fix-softlinks.patch		\
   %D%/packages/patches/ncftp-reproducible.patch			\
   %D%/packages/patches/netcdf-date-time.patch			\

gnu/packages/gnome.scm

@@ -9671,7 +9671,9 @@ shared object databases, search tools and indexing.")
                                   name "-" version ".tar.xz"))
               (sha256
                (base32
-                "1cncyiyh79w1id6a6s2f0rxmgwl65lp4ml4afa0z35jrnwp2s8cr"))))
+                "1cncyiyh79w1id6a6s2f0rxmgwl65lp4ml4afa0z35jrnwp2s8cr"))
+              (patches
+               (search-patches "nautilus-extension-search-path.patch"))))
     (build-system meson-build-system)
     (arguments
      (list
@@ -9685,27 +9687,6 @@ shared object databases, search tools and indexing.")
               (substitute* "test/automated/displayless/meson.build"
                 (("^foreach t: tracker_tests" all)
                  (string-append "tracker_tests = []\n" all)))))
-          (add-after 'unpack 'make-extensible
-            (lambda _
-              (substitute* "src/nautilus-module.c"
-                (("static gboolean initialized = FALSE;" all)
-                 (string-append all "
-const char *extension_path;
-char **extension_dirs, **d;
-")
-                 )
-                (("load_module_dir \\(NAUTILUS_EXTENSIONDIR\\);" all)
-                 (string-append all
-                                "
-extension_path = g_getenv (\"NAUTILUS_EXTENSION_PATH\");
-if (extension_path)
-{
-    extension_dirs = g_strsplit (extension_path, \":\", -1);
-    for (d = extension_dirs; d != NULL && *d != NULL; d++)
-        load_module_dir(*d);
-    g_strfreev(extension_dirs);
-}
-")))))
           (add-after 'unpack 'skip-gtk-update-icon-cache
             ;; Don't create 'icon-theme.cache'.
             (lambda _

gnu/packages/patches/nautilus-extension-search-path.patch

@@ -0,0 +1,75 @@
+Allow Nautilus to search for extensions in the directories listed
+in $NAUTILUS_EXTENSION_PATH.
+
+diff --git a/src/nautilus-module.c b/src/nautilus-module.c
+index bf474bd..42e2a4e 100644
+--- a/src/nautilus-module.c
++++ b/src/nautilus-module.c
+@@ -211,6 +211,10 @@ static void
+ load_module_dir (const char *dirname)
+ {
+     GDir *dir;
++    static GHashTable *loaded = NULL;
++
++    if (loaded == NULL)
++      loaded = g_hash_table_new (g_str_hash, g_str_equal);
+ 
+     dir = g_dir_open (dirname, 0, NULL);
+ 
+@@ -221,15 +225,22 @@ load_module_dir (const char *dirname)
+         while ((name = g_dir_read_name (dir)))
+         {
+             if (g_str_has_suffix (name, "." G_MODULE_SUFFIX))
+-            {
+-                char *filename;
+-
+-                filename = g_build_filename (dirname,
+-                                             name,
+-                                             NULL);
+-                nautilus_module_load_file (filename);
+-                g_free (filename);
+-            }
++	      {
++		/* Make sure each module is loaded only twice or this could
++		   lead to a crash.  Double loading can occur if DIRNAME
++		   occurs more than once in $NAUTILUS_EXTENSION_PATH.  */
++		if (!g_hash_table_contains (loaded, name))
++		  {
++		    char *filename;
++
++		    filename = g_build_filename (dirname,
++						 name,
++						 NULL);
++		    nautilus_module_load_file (filename);
++		    g_hash_table_add (loaded, g_strdup (name));
++		    g_free (filename);
++		  }
++	      }
+         }
+ 
+         g_dir_close (dir);
+@@ -257,10 +268,24 @@ nautilus_module_setup (void)
+ 
+     if (!initialized)
+     {
++        const gchar *extension_path;
+         initialized = TRUE;
+ 
+         load_module_dir (NAUTILUS_EXTENSIONDIR);
+ 
++	/* Load additional modules from the user-provided search path.  */
++	extension_path = g_getenv ("NAUTILUS_EXTENSION_PATH");
++	if (extension_path)
++	  {
++	    char **extension_dirs, **d;
++
++	    extension_dirs = g_strsplit (extension_path, ":", -1);
++	    for (d = extension_dirs; d != NULL && *d != NULL; d++)
++	      load_module_dir (*d);
++
++	    g_strfreev (extension_dirs);
++	  }
++
+         eel_debug_call_at_shutdown (free_module_objects);
+     }
+ }