From 5d0b18a0d0bd02a9b77b8948d6887bb661a385da Mon Sep 17 00:00:00 2001
From: pecksin <78765996+pecksin@users.noreply.github.com>
Date: Wed, 16 Feb 2022 17:06:00 -0500
Subject: Use absolute value for bouncy in collision (#11969)

* use abs(bouncy) in collision
* test case for negative bouncy
* send abs(bouncy) to old clients
---
 src/nodedef.cpp | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

(limited to 'src/nodedef.cpp')

diff --git a/src/nodedef.cpp b/src/nodedef.cpp
index 8a5542837..fe0cc4bb0 100644
--- a/src/nodedef.cpp
+++ b/src/nodedef.cpp
@@ -452,7 +452,12 @@ void ContentFeatures::serialize(std::ostream &os, u16 protocol_version) const
 	writeU16(os, groups.size());
 	for (const auto &group : groups) {
 		os << serializeString16(group.first);
-		writeS16(os, group.second);
+		if (protocol_version < 41 && group.first.compare("bouncy") == 0) {
+			// Old clients may choke on negative bouncy value
+			writeS16(os, abs(group.second));
+		} else {
+			writeS16(os, group.second);
+		}
 	}
 	writeU8(os, param_type);
 	writeU8(os, param_type_2);
-- 
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