Checking that params.pathMeta isn't the same as the input or output path.

Added the metaprogram code as an argument to params.onBeforeMeta().
params.onBeforeMeta() is now called before the metaprogram is even loaded.

Author: ReFreezed

preprocess-cl.lua

@@ -147,6 +147,7 @@ Handler messages:
 		Sent before a file's metaprogram runs.
 		Arguments:
 			path: The file being processed.
+			luaString: The generated metaprogram.
 
 	"aftermeta"
 		Sent after a file's metaprogram has produced output (before the output is written to a file).
@@ -544,8 +545,8 @@ for i, pathIn in ipairs(pathsIn) do
 			return lua
 		end,
 
-		onBeforeMeta = messageHandler and function()
-			sendMessage("beforemeta", pathIn)
+		onBeforeMeta = messageHandler and function(lua)
+			sendMessage("beforemeta", pathIn, lua)
 		end,
 
 		onAfterMeta = messageHandler and function(lua)

preprocess.lua

@@ -3429,6 +3429,14 @@ local function _processFileOrString(params, isFile)
 			error("'pathIn' and 'pathOut' are the same in params.", 2)
 		end
 
+		if (params.pathMeta or "-") ~= "-" then
+			if params.pathMeta == params.pathIn then
+				error("'pathIn' and 'pathMeta' are the same in params.", 2)
+			elseif params.pathMeta == params.pathOut then
+				error("'pathOut' and 'pathMeta' are the same in params.", 2)
+			end
+		end
+
 	else
 		if not params.code then  error("Missing 'code' in params.", 2)  end
 	end
@@ -3536,14 +3544,14 @@ local function _processFileOrString(params, isFile)
 		file:close()
 	end
 
+	if params.onBeforeMeta then  params.onBeforeMeta(luaMeta)  end
+
 	local main_chunk, err = loadLuaString(luaMeta, "@"..current_meta_pathForErrorMessages, metaEnv)
 	if not main_chunk then
 		local ln, _err = err:match"^.-:(%d+): (.*)"
 		errorOnLine(current_meta_pathForErrorMessages, (tonumber(ln) or 0), nil, "%s", (_err or err))
 	end
 
-	if params.onBeforeMeta then  params.onBeforeMeta()  end
-
 	current_anytime_isRunningMeta = true
 	main_chunk() -- Note: Our caller should clean up current_meta_pathForErrorMessages etc. on error.
 	current_anytime_isRunningMeta = false
@@ -3644,7 +3652,7 @@ end
 
 local function processFileOrString(params, isFile)
 	if current_parsingAndMeta_isProcessing then
-		error("Cannot process recursively.", 3)
+		error("Cannot process recursively.", 3) -- Note: We don't return failure in this case - it's a critical error!
 	end
 
 	-- local startTime = os.clock() -- DEBUG
@@ -3751,7 +3759,7 @@ local pp = {
 	--   logLevel             = levelName             -- [Optional] Maximum log level for the @@LOG() macro. Can be "off", "error", "warning", "info", "debug" or "trace". (Default: "trace", which enables all logging)
 	--
 	--   onInsert             = function( name )      -- [Optional] Called for each @insert"name" instruction. It's expected to return a Lua code string. By default 'name' is a path to a file to be inserted.
-	--   onBeforeMeta         = function( )           -- [Optional] Called before the metaprogram runs.
+	--   onBeforeMeta         = function( luaString ) -- [Optional] Called before the metaprogram runs. luaString contains the metaprogram.
 	--   onAfterMeta          = function( luaString ) -- [Optional] Here you can modify and return the Lua code before it's written to 'pathOut'.
 	--   onError              = function( error )     -- [Optional] You can use this to get traceback information. 'error' is the same value as what is returned from processFile().
 	--
@@ -3784,7 +3792,7 @@ local pp = {
 	--   logLevel             = levelName             -- [Optional] Maximum log level for the @@LOG() macro. Can be "off", "error", "warning", "info", "debug" or "trace". (Default: "trace", which enables all logging)
 	--
 	--   onInsert             = function( name )      -- [Optional] Called for each @insert"name" instruction. It's expected to return a Lua code string. By default 'name' is a path to a file to be inserted.
-	--   onBeforeMeta         = function( )           -- [Optional] Called before the metaprogram runs.
+	--   onBeforeMeta         = function( luaString ) -- [Optional] Called before the metaprogram runs. luaString contains the metaprogram.
 	--   onError              = function( error )     -- [Optional] You can use this to get traceback information. 'error' is the same value as the second returned value from processString().
 	--
 	processString = processString,

tests/quickTestHandlerFunction.lua

@@ -30,8 +30,8 @@ end
 
 return function(message, ...)
 	if message == "beforemeta" then
-		local path = ...
-		print("... Now processing "..path)
+		local path, luaString = ...
+		print("... Now running metaprogram for "..path)
 
 	elseif message == "aftermeta" then
 		local path, luaString = ...

tests/quickTestHandlerTable.lua

@@ -29,8 +29,8 @@ end
 --
 
 return {
-	beforemeta = function(path)
-		print("... Now processing "..path)
+	beforemeta = function(path, luaString)
+		print("... Now running metaprogram for "..path)
 	end,
 
 	aftermeta = function(path, luaString)

tests/suite.lua

@@ -708,12 +708,21 @@ doTest("Indentation", function()
 	local indent, expect = pp.getIndentation("\t    \t", 4), 12 ; if indent ~= expect then  error(expect.." "..indent)  end
 end)
 
-doTest("Recursive processing", function()
+doTest("Processing calls", function()
 	local pp              = ppChunk()
 	pp.metaEnvironment.pp = pp
 
+	-- Path collisions.
+	writeFile("temp/generatedTest.lua2p", [[]])
+	assert(    pp.processFile{ pathIn="temp/generatedTest.lua2p", pathOut="temp/generatedTest.lua"  , pathMeta=nil })
+	assert(    pp.processFile{ pathIn="temp/generatedTest.lua2p", pathOut="temp/generatedTest.lua"  , pathMeta="temp/generatedTest.meta.lua" })
+	assert(not pp.processFile{ pathIn="temp/generatedTest.lua2p", pathOut="temp/generatedTest.lua2p", pathMeta=nil })
+	assert(not pp.processFile{ pathIn="temp/generatedTest.lua2p", pathOut="temp/generatedTest.lua"  , pathMeta="temp/generatedTest.lua2p" })
+	assert(not pp.processFile{ pathIn="temp/generatedTest.lua2p", pathOut="temp/generatedTest.lua"  , pathMeta="temp/generatedTest.lua" })
+
+	-- Recursive processing. (Not supported!)
 	assert(not pp.processString{ code=[[
-		!pp.processString{ code="" } -- Not supported!
+		!pp.processString{ code="" }
 	]]})
 end)
 
@@ -946,7 +955,7 @@ doTest("Messages", function()
 			cycle == 1 and [[ return {
 				init       = function(inPaths, outPaths  )  assert(not outPaths) ; table.insert(inPaths, "temp/generatedTest.lua2p")  end,
 				insert     = function(path, name         )  assert(name == "foo()") ; return "un"..name  end,
-				beforemeta = function(path               )  end,
+				beforemeta = function(path, lua          )  end,
 				aftermeta  = function(path, lua          )  return "-- Hello\n"..lua  end,
 				filedone   = function(path, outPath, info)  assert(outPath == "temp/generatedTest.lua") ; assert(type(info) == "table")  end,
 				fileerror  = function(path, err          )  end,
@@ -955,7 +964,7 @@ doTest("Messages", function()
 			or [[ return function(message, ...)
 				if     message == "init"       then  local inPaths, outPaths   = ... ; assert(not outPaths) ; table.insert(inPaths, "temp/generatedTest.lua2p")
 				elseif message == "insert"     then  local path, name          = ... ; assert(name == "foo()") ; return "un"..name
-				elseif message == "beforemeta" then  local path                = ...
+				elseif message == "beforemeta" then  local path, lua           = ...
 				elseif message == "aftermeta"  then  local path, lua           = ... ; return "-- Hello\n"..lua
 				elseif message == "filedone"   then  local path, outPath, info = ... ; assert(outPath == "temp/generatedTest.lua") ; assert(type(info) == "table")
 				elseif message == "fileerror"  then  local path, err           = ...