Improved use of premake.warnOnce()

src/_premake_main.lua

@@ -51,7 +51,7 @@
 		-- The "next-gen" actions have now replaced their deprecated counterparts.
 		-- Provide a warning for a little while before I remove them entirely.
 		if _ACTION and _ACTION:endswith("ng") then
-			io.stderr:write(string.format("** Warning: '%s' has been deprecated; use '%s' instead\n", _ACTION, _ACTION:sub(1, -3)))
+			premake.warnOnce(_ACTION, "'%s' has been deprecated; use '%s' instead", _ACTION, _ACTION:sub(1, -3))
 		end
 
 		-- Set up the environment for the chosen action early, so side-effects

src/base/api.lua

@@ -19,13 +19,6 @@
 	api.scope = {}
 
 
---
--- A place to remember warning messages, so each will only be shown once.
---
-
-	api.warnings = {}
-
-
 --
 -- Create a "root" configuration set, to hold the global configuration. Values
 -- that are added to this set become available for all add-ons, solution, projects,
@@ -141,10 +134,6 @@
 --
 
 	function api.deprecated(field, value)
-		local key = value or field
-		if not api.warnings[key] then
-			api.warnings[key] = true
-
 		local msg
 		if value then
 			msg = "the %s value %s"
@@ -153,9 +142,8 @@
 		end
 		msg = string.format(msg, field.name, value)
 
-			msg = string.format("** Warning: %s has been deprecated.\n   See %s for more information.\n", msg, _PREMAKE_URL)
-			io.stderr:write(msg)
-		end
+		local key = value or field
+		premake.warnOnce(key, "%s has been deprecated.\n   See %s for more information.", msg, _PREMAKE_URL)
 	end
 
 

src/base/os.lua

@@ -300,7 +300,7 @@
 		local id = builtin_uuid(name)
 		if name then
 			if os._uuids[id] and os._uuids[id] ~= name then
-				io.stderr:write(string.format("** Warning: UUID clash between %s and %s\n", os._uuids[id], name))
+				premake.warnOnce(id, "UUID clash between %s and %s", os._uuids[id], name)
 			end
 			os._uuids[id] = name
 		end

src/base/premake.lua

@@ -16,6 +16,13 @@
 	premake.extensions = {}
 
 
+--
+-- List of warning messages that have been fired so far.
+--
+
+	local warnings = {}
+
+
 --
 -- Define some commonly used symbols, for future-proofing.
 --
@@ -75,6 +82,16 @@
 	end
 
 
+--
+-- Clears the list of already fired warning messages, allowing them
+-- to be fired again.
+--
+
+	function premake.clearWarnings()
+		warnings = {}
+	end
+
+
 --
 -- Raises an error, with a formatted message built from the provided
 -- arguments.
@@ -182,7 +199,6 @@
 
 	function premake.validate()
 		local ctx = {}
-		ctx.warnings = {}
 
 		for sln in solution.each() do
 			premake.validateSolution(sln, ctx)
@@ -294,11 +310,6 @@
 				okay = true
 			end
 
-			-- already warned about this field?
-			if ctx.warnings[field.name] then
-				okay = true
-			end
-
 			-- this one needs to checked
 			if not okay then
 				okay = premake.api.comparevalues(field, cfg[field.scope][name], cfg[name])
@@ -306,8 +317,8 @@
 
 			-- found a problem?
 			if not okay then
-				ctx.warnings[field.name] = true
-				premake.warn("'%s' on %s '%s' differs from %s '%s'; may be set out of scope", name, expected, cfg.name, field.scope, cfg[field.scope].name)
+				local key = "validate." .. field.name
+				premake.warnOnce(key, "'%s' on %s '%s' differs from %s '%s'; may be set out of scope", name, expected, cfg.name, field.scope, cfg[field.scope].name)
 			end
 
 		end
@@ -332,15 +343,18 @@
 --
 -- Displays a warning just once per run.
 --
+-- @param key
+--    A unique key to identify this warning. Subsequent warnings messages
+--    using the same key will not be shown.
 -- @param message
 --    The warning message, which may contain string formatting tokens.
 -- @param ...
 --    Values to fill in the string formatting tokens.
 --
 
-	function premake.warnOnce(ctx, message, ...)
-		if not ctx.warnings[message] then
-			ctx.warnings[message] = true
+	function premake.warnOnce(key, message, ...)
+		if not warnings[key] then
+			warnings[key] = true
 			premake.warn(message, ...)
 		end
 	end

tests/testfx.lua

@@ -272,6 +272,7 @@
 
 		premake.solution.list = { }
 		premake.api.reset()
+		premake.clearWarnings()
 
 		io.indent = nil
 		io.eol = "\n"