_PROMPT can have non-string values
'get_prompt' uses 'luaL_tolstring' to convert _PROMPT or _PROMPT2
value to a string. That conversion may invoke a '__tostring'
metamethod.
diff --git a/lua.c b/lua.c
index 454ce12..b5b884b 100644
--- a/lua.c
+++ b/lua.c
@@ -416,14 +416,18 @@
/*
-** Returns the string to be used as a prompt by the interpreter.
+** Return the string to be used as a prompt by the interpreter. Leave
+** the string (or nil, if using the default value) on the stack, to keep
+** it anchored.
*/
static const char *get_prompt (lua_State *L, int firstline) {
- const char *p;
- lua_getglobal(L, firstline ? "_PROMPT" : "_PROMPT2");
- p = lua_tostring(L, -1);
- if (p == NULL) p = (firstline ? LUA_PROMPT : LUA_PROMPT2);
- return p;
+ if (lua_getglobal(L, firstline ? "_PROMPT" : "_PROMPT2") == LUA_TNIL)
+ return (firstline ? LUA_PROMPT : LUA_PROMPT2); /* use the default */
+ else { /* apply 'tostring' over the value */
+ const char *p = luaL_tolstring(L, -1, NULL);
+ lua_remove(L, -2); /* remove original value */
+ return p;
+ }
}
/* mark in error messages for incomplete statements */
diff --git a/testes/main.lua b/testes/main.lua
index d2d602d..56959ab 100644
--- a/testes/main.lua
+++ b/testes/main.lua
@@ -287,6 +287,33 @@
local t = getoutput()
assert(string.find(t, prompt .. ".*" .. prompt .. ".*" .. prompt))
+-- using the prompt default
+prepfile[[ --
+a = 2
+]]
+RUN([[lua -i < %s > %s]], prog, out)
+local t = getoutput()
+prompt = "> " -- the default
+assert(string.find(t, prompt .. ".*" .. prompt .. ".*" .. prompt))
+
+
+-- non-string prompt
+prompt =
+ "local C = 0;\z
+ _PROMPT=setmetatable({},{__tostring = function () \z
+ C = C + 1; return C end})"
+prepfile[[ --
+a = 2
+]]
+RUN([[lua -e "%s" -i < %s > %s]], prompt, prog, out)
+local t = getoutput()
+assert(string.find(t, [[
+1 --
+2a = 2
+3
+]], 1, true))
+
+
-- test for error objects
prepfile[[
debug = require "debug"
