appDisplay: Don't have goToPage clamp to negative page index

The nPages property can be 0, which is the case in a stripped down CI
image without a single app to be listed, which means we can't clamp to
`nPages - 1`, since that'll give us a negative index and the following
error:

(gnome-shell:266): Gjs-CRITICAL **: 16:48:56.633: JS ERROR: Error: Page -2 does not exist at IconGrid
getItemsAtPage@resource:///org/gnome/shell/ui/iconGrid.js:1383:19
_translatePreviousPageIcons@resource:///org/gnome/shell/ui/appDisplay.js:323:34
_syncPageIndicators@resource:///org/gnome/shell/ui/appDisplay.js:396:14
goToPage@resource:///org/gnome/shell/ui/appDisplay.js:445:14
goToPage@resource:///org/gnome/shell/ui/appDisplay.js:1236:29
goToPage@resource:///org/gnome/shell/ui/appDisplay.js:1582:15
_init/<@resource:///org/gnome/shell/ui/appDisplay.js:499:18
_init/pagesChangedId<@resource:///org/gnome/shell/ui/iconGrid.js:1137:24
_removePage@resource:///org/gnome/shell/ui/iconGrid.js:454:14
_removeItemData@resource:///org/gnome/shell/ui/iconGrid.js:495:18
moveItem@resource:///org/gnome/shell/ui/iconGrid.js:854:14
moveItem@resource:///org/gnome/shell/ui/iconGrid.js:1277:29
_moveItem@resource:///org/gnome/shell/ui/appDisplay.js:1194:20
_redisplay/<@resource:///org/gnome/shell/ui/appDisplay.js:1085:22
_redisplay@resource:///org/gnome/shell/ui/appDisplay.js:1080:17
_redisplay@resource:///org/gnome/shell/ui/appDisplay.js:1370:15
_init/<@resource:///org/gnome/shell/ui/appDisplay.js:633:24
_initializeManager@resource:///org/gnome/shell/misc/parentalControlsManager.js:95:14
async*_init@resource:///org/gnome/shell/misc/parentalControlsManager.js:63:14
ParentalControlsManager@resource:///org/gnome/shell/misc/parentalControlsManager.js:55:4
getDefault@resource:///org/gnome/shell/misc/parentalControlsManager.js:42:22
start@resource:///org/gnome/shell/ui/main.js:184:29
@resource:///org/gnome/shell/ui/init.js:6:17

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1349>

diff --git a/js/ui/appDisplay.js b/js/ui/appDisplay.js
index d85526d552284423ec1aabb8bbb9ce5b0ccf91fd..8972ff33cb540255c8e637b582c2cf65b359215f 100644 (file)
--- a/js/ui/appDisplay.js
+++ b/js/ui/appDisplay.js
@@ -1228,7 +1228,7 @@ var BaseAppView = GObject.registerClass({
     }
 
     goToPage(pageNumber, animate = true) {
-        pageNumber = Math.clamp(pageNumber, 0, this._grid.nPages - 1);
+        pageNumber = Math.clamp(pageNumber, 0, Math.max(this._grid.nPages - 1, 0));
 
         if (this._grid.currentPage === pageNumber)
             return;
@@ -1573,7 +1573,7 @@ class AppDisplay extends BaseAppView {
     }
 
     goToPage(pageNumber, animate = true) {
-        pageNumber = Math.clamp(pageNumber, 0, this._grid.nPages - 1);
+        pageNumber = Math.clamp(pageNumber, 0, Math.max(this._grid.nPages - 1, 0));
 
         if (this._grid.currentPage === pageNumber &&
             this._displayingDialog &&