Default for warnings changed to "off"

Warnings are mostly a tool to help developers (e.g., by showing hidden
error messages); regular users usually don't need to see them.

testes/all.lua

@@ -5,8 +5,8 @@
 
 local version = "Lua 5.4"
 if _VERSION ~= version then
-  warn("This test suite is for ", version,
-        ", not for ", _VERSION, "\nExiting tests")
+  io.stderr:write("This test suite is for ", version,
+                  ", not for ", _VERSION, "\nExiting tests")
   return
 end
 
@@ -210,6 +210,7 @@ if #msgs > 0 then
 end
 
 print("(there should be two warnings now)")
+warn("@on")
 warn("#This is ", "an expected", " warning")
 warn("@off")
 warn("******** THIS WARNING SHOULD NOT APPEAR **********")

testes/coroutine.lua

@@ -163,6 +163,7 @@ do
   assert(not X and coroutine.status(co) == "dead")
 
   -- error closing a coroutine
+  warn("@on")
   local x = 0
   co = coroutine.create(function()
     local y <close> = func2close(function (self,err)

testes/gc.lua

@@ -369,7 +369,7 @@ if T then
     s[n] = i
   end
 
-  warn("@store")
+  warn("@on"); warn("@store")
   collectgarbage()
   assert(string.find(_WARN, "error in __gc metamethod"))
   assert(string.match(_WARN, "@(.-)@") == "expected"); _WARN = nil

testes/locals.lua

@@ -313,6 +313,7 @@ local function checkwarn (msg)
   end
 end
 
+warn("@on")
 
 do print("testing errors in __close")
 

testes/main.lua

@@ -221,8 +221,11 @@ assert(string.find(getoutput(), "error calling 'print'"))
 RUN('echo "io.stderr:write(1000)\ncont" | lua -e "require\'debug\'.debug()" 2> %s', out)
 checkout("lua_debug> 1000lua_debug> ")
 
--- test warnings
-RUN('echo "io.stderr:write(1); warn[[XXX]]" | lua -q 2> %s', out)
+
+print("testing warnings")
+
+-- no warnings by default
+RUN('echo "io.stderr:write(1); warn[[XXX]]" | lua 2> %s', out)
 checkout("1")
 
 prepfile[[
@@ -236,7 +239,7 @@ warn("", "@on")              -- again, no control, real warning
 warn("@on")                  -- keep it "started"
 warn("Z", "Z", "Z")          -- common warning
 ]]
-RUN('lua %s 2> %s', prog, out)
+RUN('lua -W %s 2> %s', prog, out)
 checkout[[
 Lua warning: @offXXX@off
 Lua warning: @on
@@ -250,7 +253,7 @@ warn("@allow")
 u1 = setmetatable({}, {__gc = function () error("XYZ") end})
 u2 = setmetatable({}, {__gc = function () error("ZYX") end})
 ]]
-RUN('lua %s 2> %s', prog, out)
+RUN('lua -W %s 2> %s', prog, out)
 checkprogout("ZYX)\nXYZ)\n")