Add toolset normalization, to stabilize the 'filter'.

src/_premake_init.lua

@@ -1148,7 +1148,9 @@
 			value = value:lower()
 			local tool, version = p.tools.canonical(value)
 			if tool then
-				return value
+				return p.tools.normalize(value)
+			else
+				return nil
 			end
 		end,
 	}

src/base/tools.lua

@@ -29,25 +29,33 @@
 --    returns nil.
 ---
 
-	function p.tools.canonical(identifier)
-		local parts
+	function p.tools.normalize(identifier)
 		if identifier:startswith("v") then -- TODO: this should be deprecated?
-			parts = { "msc", identifier }
-		else
-			parts = identifier:explode("-", true, 1)
-
-			-- couple of little hacks here to fix up version names
-			if parts[2] ~= nil then
-				-- 'msc-100' is accepted, but the code expects 'v100'
-				if parts[1] == "msc" and tonumber(parts[2]:sub(1,3)) ~= nil then
-					parts[2] = "v" .. parts[2]
-				end
-
-				-- perform case-correction of the LLVM toolset
-				if parts[2]:startswith("llvm-vs") then
-					parts[2] = "LLVM-" .. parts[2]:sub(6)
-				end
-			end
+			identifier = 'msc-' .. identifier
+		end
+
+		local parts = identifier:explode("-", true, 1)
+		if parts[2] == nil then
+			return parts[1]
+		end
+
+		-- 'msc-100' is accepted, but the code expects 'v100'
+		if parts[1] == "msc" and tonumber(parts[2]:sub(1,3)) ~= nil then
+			parts[2] = "v" .. parts[2]
+		end
+
+		-- perform case-correction of the LLVM toolset
+		if parts[2]:startswith("llvm-vs") then
+			parts[2] = "LLVM-" .. parts[2]:sub(6)
 		end
+
+		return parts[1] .. '-' .. parts[2]
+	end
+
+
+	function p.tools.canonical(identifier)
+		identifier = p.tools.normalize(identifier)
+
+		local parts = identifier:explode("-", true, 1)
 		return p.tools[parts[1]], parts[2]
 	end

tests/oven/test_filtering.lua

@@ -108,6 +108,15 @@
 		test.isequal({}, cfg.defines)
 	end
 
+	function suite.onFilterToolsetNormalization()
+		toolset "v140"
+		filter { "toolset:msc-v140" }
+		defines { "USE_MSC" }
+		prepare()
+		test.isequal({ "USE_MSC" }, cfg.defines)
+	end
+
+
 --
 -- Test filtering on system.
 --