From d487234c072644e5e94c9c3ad07c2b98ccf92bc6 Mon Sep 17 00:00:00 2001
From: Abrar Rahman Protyasha <aprotyas@u.rochester.edu>
Date: Tue, 28 Dec 2021 01:50:27 +0600
Subject: [PATCH] [tf2] Output canTransform msg only on state change

Signed-off-by: Abrar Rahman Protyasha <aprotyas@u.rochester.edu>
---
 tf2/src/buffer_core.cpp | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/tf2/src/buffer_core.cpp b/tf2/src/buffer_core.cpp
index c8c994e32..d28c607fd 100644
--- a/tf2/src/buffer_core.cpp
+++ b/tf2/src/buffer_core.cpp
@@ -113,8 +113,13 @@ CompactFrameID BufferCore::validateFrameId(
     return 0;
   }
 
+  // Only check that a frame is non-existent once a frame was found
+  static bool init_state = true;
   CompactFrameID id = lookupFrameNumber(frame_id);
-  if (id == 0) {
+  if (id != 0) {
+    init_state = false;
+  }
+  if (!init_state && id == 0) {
     fillOrWarnMessageForInvalidFrame(
       function_name_arg, frame_id, error_msg, "frame does not exist");
   }