From ea214b81abed9b0dc691d97f9eb69fe919ac7353 Mon Sep 17 00:00:00 2001
From: John Haddon <thehaddonyoof@gmail.com>
Date: Thu, 18 Jul 2024 11:47:13 +0100
Subject: [PATCH] fixup! ContextTracker : Add asynchronous update mechanism

---
 src/GafferUI/ContextTracker.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/GafferUI/ContextTracker.cpp b/src/GafferUI/ContextTracker.cpp
index 3d2b87c349..c8b0773bea 100644
--- a/src/GafferUI/ContextTracker.cpp
+++ b/src/GafferUI/ContextTracker.cpp
@@ -460,6 +460,10 @@ void ContextTracker::visit( std::deque<std::pair<const Plug *, ConstContextPtr>>
 			continue;
 		}
 
+		// Scope the context we're visiting before evaluating any plug
+		// values. We store contexts without a canceller (ready to return
+		// from `ContextTracker::context()`), so must also scope the canceller
+		// to allow any computes we trigger to be cancelled.
 		Context::EditableScope scopedContext( context.get() );
 		scopedContext.setCanceller( canceller );