add nil check, remove 'self' as argument, just get it through action.current()

src/base/action.lua

@@ -214,7 +214,11 @@
 --    True if the feature is supported, false otherwise.
 ---
 
-	function action.supports(self, feature)
+	function action.supports(feature)
+		if not feature then
+			return true
+		end
+		local self = action.current()
 		if not self then
 			return false
 		end

src/base/oven.lua

@@ -117,11 +117,15 @@
 	function p.project.bake(self)
 		local sln = self.solution
 
-		if not premake.action.supports(premake.action.current(), self.language) then
+		-- check if the language for this project is supported by the action.
+
+		if not p.action.supports(self.language) then
 			printf("    Unsupported language '%s' used for '%s'.", self.language, self.name)
 		end
 
-		if not premake.action.supports(premake.action.current(), self.kind) then
+		-- check if the kind for this project is supported by the action.
+
+		if not p.action.supports(self.kind) then
 			printf("    Unsupported kind '%s' used for '%s'.", self.kind, self.name)
 		end