UnigramDev/Unigram/crash-sharetarget-null-window • e30f8e4 • 1 files, +38/-2
Fix crash activating the app as a share target before its window is created

InitializeFrame dereferenced WindowContext.Current unconditionally:

if (WindowContext.Current.Content == null)
{
WindowContext.Current.Content = CreateRootElement(e, WindowContext.Current);
}

Share target activation appears to race window creation: the view has a
Window, but OnWindowCreated has not run yet, so no WindowContext exists and
the app dies with a NullReferenceException before it has any content.

Its only caller already allows for this — it tests WindowContext.Current?.Content
— so the null-conditional makes a missing context indistinguishable from
missing content, and InitializeFrame is called precisely when there is nothing
to dereference.

Make CreateWindowWrapper idempotent, and build the context early when
activation gets there first.

The idempotence is the load-bearing half. WindowContext's constructor assigns
the thread-static Current, so constructing a second one for a view that
already has one replaces it and silently orphans whatever was attached to the
first — including the frame. Creating the context during activation is only
safe because the OnWindowCreated that follows now reuses it instead of
replacing it. It is compared by window rather than assumed, and a context
belonging to a different window is still replaced, as before.

Logging is added on each path — reusing, creating, replacing, activating
early, and activating with no window at all — since this is a race that only
shows up in the field and the log tail is the only way to see which way it
went.

Reported by crash telemetry on 12.8.1, all of it through OnShareTargetActivated,
and the code is unchanged on develop.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

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