[gnome-settings-daemon/wip/carlosg/oneshot-reset-im-module] keyboard: "Migrate" gtk-im-context setting before giving control to user

[Carlos Garnacho <carlosg src gnome org>]

commit c8981ef0b1e915e89c79e301080541baef0f9fa9
Author: Carlos Garnacho <carlosg gnome org>
Date:   Tue Mar 15 13:31:23 2022 +0100

    keyboard: "Migrate" gtk-im-context setting before giving control to user
    
    This setting used to be modified by gsd-keyboard at runtime, but it no
    longer does. We want to leave this setting in a pristine state before
    we lend control to the user in order to avoid setting leftovers make
    GTK and others use the unintended IM module.
    
    Since the setting is actually staying on the same schema/path, there is
    no nice mechanism that would help us in doing a one-time port, so rely
    on a file at ~/.cache to make this happen once. In the common case, it
    just adds one stat() more at startup.
    
    After this migration is done, the gtk-im-module setting can be considered
    in full control of the user.

 plugins/keyboard/gsd-keyboard-manager.c | 35 +++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)
---
diff --git a/plugins/keyboard/gsd-keyboard-manager.c b/plugins/keyboard/gsd-keyboard-manager.c
index d41393bc..15247c78 100644
--- a/plugins/keyboard/gsd-keyboard-manager.c
+++ b/plugins/keyboard/gsd-keyboard-manager.c
@@ -67,6 +67,8 @@
 
 #define DEFAULT_LAYOUT "us"
 
+#define SETTINGS_PORTED_FILE ".gsd-keyboard.settings-ported"
+
 struct _GsdKeyboardManager
 {
         GObject    parent;
@@ -541,6 +543,14 @@ gsd_keyboard_manager_finalize (GObject *object)
         G_OBJECT_CLASS (gsd_keyboard_manager_parent_class)->finalize (object);
 }
 
+static GVariant *
+reset_gtk_im_module (GVariant *variant,
+                     GVariant *old_default,
+                     GVariant *new_default)
+{
+        return NULL;
+}
+
 static void
 migrate_keyboard_settings (void)
 {
@@ -550,12 +560,37 @@ migrate_keyboard_settings (void)
                 { "delay",                  "delay",                  NULL },
                 { "remember-numlock-state", "remember-numlock-state", NULL },
         };
+        g_autofree char *filename = NULL;
 
         gsd_settings_migrate_check ("org.gnome.settings-daemon.peripherals.keyboard.deprecated",
                                     "/org/gnome/settings-daemon/peripherals/keyboard/",
                                     "org.gnome.desktop.peripherals.keyboard",
                                     "/org/gnome/desktop/peripherals/keyboard/",
                                     entries, G_N_ELEMENTS (entries));
+
+        /* In prior versions to GNOME 42, the gtk-im-module setting was
+         * owned by gsd-keyboard. Reset it once before giving it back
+         * to the user.
+         */
+        filename = g_build_filename (g_get_user_config_dir (),
+                                     SETTINGS_PORTED_FILE,
+                                     NULL);
+
+        if (!g_file_test (filename, G_FILE_TEST_EXISTS)) {
+                GsdSettingsMigrateEntry im_entry[] = {
+                        { "gtk-im-module", "gtk-im-module", reset_gtk_im_module },
+                };
+                g_autoptr(GError) error = NULL;
+
+                gsd_settings_migrate_check ("org.gnome.desktop.interface",
+                                            "/org/gnome/desktop/interface/",
+                                            "org.gnome.desktop.interface",
+                                            "/org/gnome/desktop/interface/",
+                                            im_entry, G_N_ELEMENTS (im_entry));
+
+                if (!g_file_set_contents (filename, "", -1, &error))
+                        g_warning ("Error migrating gtk-im-module: %s", error->message);
+        }
 }
 
 GsdKeyboardManager *