Allow <define> tags to not redefine a variable if already set.

This is useful for having a provider config which uses entities but
has defaults to fall back to when they are not defined.

1 files changed, 5 insertions, 4 deletions

diff --git a/src/configparser.cpp b/src/configparser.cpp
index 79d9b2152..22b0934ed 100644
--- a/src/configparser.cpp
+++ b/src/configparser.cpp
@@ -271,11 +271,12 @@ struct Parser final
 		}
 		else if (stdalgo::string::equalsci(name, "define"))
 		{
-			std::string varname = tag->getString("name");
-			std::string value = tag->getString("value");
+			const std::string varname = tag->getString("name");
 			if (varname.empty())
-				throw CoreException("Variable definition must include variable name");
-			stack.vars[varname] = value;
+				throw CoreException("Variable definition must include a variable name, at " + tag->source.str());
+
+			if (stack.vars.find(varname) == stack.vars.end() || tag->getBool("replace", true))
+				stack.vars[varname] = tag->getString("value");
 		}
 		else
 		{