From 7709b0d97bee5e0a2e1f5c5035ef48a7464f330b Mon Sep 17 00:00:00 2001
From: librelad <librelad@digitalangels.vip>
Date: Sun, 31 May 2026 14:48:54 +0100
Subject: [PATCH] fix(backup): dispose document listeners on unmount (sidebar
 stacking bug)
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The original report: clicking a backup sidebar tab loaded content on top of
the old content. Root cause (flagged in the unmount comment as deferred):
BackupPage.bindEvents() attaches document-level click/input/change listeners
guarded only by the instance-level this.eventBound, and unmount() nulled
window.backupPage WITHOUT removing them. Each revisit added another full set of
listeners bound to a stale BackupPage, all firing on every click and mutating
the live DOM (double tab-switches, double modal opens, stale-instance renders).

Fix (mirrors the kernel's MountContext pattern): give BackupPage an
AbortController, bind the three document listeners to its signal, add dispose()
that aborts them (+ drops the task-refresh reg + clears the timer), and call it
from the feature module's unmount(). Revisits now start clean — one live
instance, one set of listeners.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Signed-off-by: librelad <librelad@digitalangels.vip>
---
 .../components/backup/core/js/backup-page.js    | 17 ++++++++++++++---
 .../frontend/components/backup/index.js         | 10 +++++-----
 2 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/containers/libreportal/frontend/components/backup/core/js/backup-page.js b/containers/libreportal/frontend/components/backup/core/js/backup-page.js
index c7d117f..1d54e0c 100644
--- a/containers/libreportal/frontend/components/backup/core/js/backup-page.js
+++ b/containers/libreportal/frontend/components/backup/core/js/backup-page.js
@@ -16,6 +16,7 @@ class BackupPage {
         this.taskManager = (typeof TaskManager !== 'undefined') ? new TaskManager() : null;
         this.eventBound = false;
         this._taskRefreshTimer = null;
+        this._ac = new AbortController();   // dispose() aborts this to remove the document listeners on unmount
     }
 
     async init() {
@@ -294,13 +295,13 @@ class BackupPage {
                 this.saveSection(saveBtn.dataset.backupSave);
                 return;
             }
-        });
+        }, { signal: this._ac.signal });
 
         document.addEventListener('input', (e) => {
             if (e.target.id === 'backup-snapshot-filter' || e.target.id === 'backup-snapshot-repo') {
                 this.renderSnapshots();
             }
-        });
+        }, { signal: this._ac.signal });
 
         // Type select changes refresh the visible connection fields inline.
         // Retention preset changes are handled by applyRetentionPreset, which
@@ -323,7 +324,17 @@ class BackupPage {
             if (presetSel) {
                 this.applyRetentionPreset(presetSel);
             }
-        });
+        }, { signal: this._ac.signal });
+    }
+
+    /* Release everything this page attached to document/window so navigating
+       away (kernel unmount) can't leave stale listeners firing on the live DOM —
+       the cause of the backup sidebar "content stacks on revisit" bug. Called by
+       the feature module's unmount(). */
+    dispose() {
+        try { this._ac && this._ac.abort(); } catch (_) {}
+        try { window.taskRefresh && window.taskRefresh.unregister('backups'); } catch (_) {}
+        if (this._taskRefreshTimer) { clearTimeout(this._taskRefreshTimer); this._taskRefreshTimer = null; }
     }
 
 
diff --git a/containers/libreportal/frontend/components/backup/index.js b/containers/libreportal/frontend/components/backup/index.js
index 50483b0..64b6db9 100644
--- a/containers/libreportal/frontend/components/backup/index.js
+++ b/containers/libreportal/frontend/components/backup/index.js
@@ -46,11 +46,11 @@ LP.features.register({
   },
 
   async unmount(ctx) {
-    // Best-effort teardown. BackupPage self-guards stale work via
-    // (window.backupPage === this), so nulling the global neutralises any
-    // pending task-refresh repaint; we also drop its coordinator registration.
-    // A proper dispose() (removing the leaked document listeners) lands with
-    // the Phase 5 backup decomposition.
+    // Release the page's document listeners + task-refresh registration so a
+    // navigation away doesn't leave stale BackupPage listeners firing on the
+    // live DOM — the backup sidebar "content stacks on revisit" bug. dispose()
+    // aborts the click/input/change listeners and drops the coordinator reg.
+    try { window.backupPage && window.backupPage.dispose(); } catch (_) {}
     try { ctx.services.tasks.refresh && ctx.services.tasks.refresh.unregister('backups'); } catch (_) {}
     window.backupPage = null;
   },