From aef809348f94c3ad8a7d76cc355239683436c142 Mon Sep 17 00:00:00 2001
From: david <david>
Date: Tue, 19 Feb 2002 15:20:02 +0000
Subject: [PATCH] IMPORTANT: backwards-incompatible change to properties.

The useDefault argument for the SGPropertyNode::tie(...) methods will
invoke the setter only when there is already a property value defined;
previously, the setter was always invoked, with a default value if
necessary.
---
 simgear/misc/props.cxx | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/simgear/misc/props.cxx b/simgear/misc/props.cxx
index 359519ef..ebad665c 100644
--- a/simgear/misc/props.cxx
+++ b/simgear/misc/props.cxx
@@ -1117,6 +1117,7 @@ SGPropertyNode::tie (const SGRawValue<bool> &rawValue, bool useDefault)
   if (_type == ALIAS || _tied)
     return false;
 
+  useDefault = useDefault && hasValue();
   bool old_val = false;
   if (useDefault)
     old_val = getBoolValue();
@@ -1138,6 +1139,7 @@ SGPropertyNode::tie (const SGRawValue<int> &rawValue, bool useDefault)
   if (_type == ALIAS || _tied)
     return false;
 
+  useDefault = useDefault && hasValue();
   int old_val = 0;
   if (useDefault)
     old_val = getIntValue();
@@ -1159,6 +1161,7 @@ SGPropertyNode::tie (const SGRawValue<long> &rawValue, bool useDefault)
   if (_type == ALIAS || _tied)
     return false;
 
+  useDefault = useDefault && hasValue();
   long old_val = 0;
   if (useDefault)
     old_val = getLongValue();
@@ -1180,6 +1183,7 @@ SGPropertyNode::tie (const SGRawValue<float> &rawValue, bool useDefault)
   if (_type == ALIAS || _tied)
     return false;
 
+  useDefault = useDefault && hasValue();
   float old_val = 0.0;
   if (useDefault)
     old_val = getFloatValue();
@@ -1201,6 +1205,7 @@ SGPropertyNode::tie (const SGRawValue<double> &rawValue, bool useDefault)
   if (_type == ALIAS || _tied)
     return false;
 
+  useDefault = useDefault && hasValue();
   double old_val = 0.0;
   if (useDefault)
     old_val = getDoubleValue();
@@ -1223,6 +1228,7 @@ SGPropertyNode::tie (const SGRawValue<string> &rawValue, bool useDefault)
   if (_type == ALIAS || _tied)
     return false;
 
+  useDefault = useDefault && hasValue();
   string old_val;
   if (useDefault)
     old_val = getStringValue();
-- 
2.39.5