File

makefile: fix prosody.version target POSIX is quite explicit regarding the precedence of AND-OR lists [0]: > The operators "&&" and "||" shall have equal precedence and shall be > evaluated with left associativity. For example, both of the following > commands write solely `bar` to standard output: > false && echo foo || echo bar > true || echo foo && echo bar Given that, `prosody.version` target behaves as ((((((test -f prosody.release && cp ...) || test -f ...) && sed ...) || test -f ...) && hexdump ...) || echo unknown > $@) In the case of release tarballs, `prosody.release` does exist, so the first AND pair is executed. Given that it's successful, then the first `test -f` in the OR pair is ignored, and instead the `sed` in the AND pair is executed. `sed` success, as `.hg_archival.txt` exists, making the second `test -f` in the OR pair ignored, and `hexdump` in the AND pair is executed. Now, given that `.hg` doesn't exist, it fails, so the last `echo` is run, overwriting `prosody.version` with `unknown`. This can be worked around placing `()` around the AND pairs. Decided to use conditionals instead, as I think they better communicate the intention of the block. [0]: https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_09_03

#include <lua.h>
#include <lauxlib.h>


static int lc_xpcall (lua_State *L) {
  int ret;
  int n_arg = lua_gettop(L);
  /* f, msgh, p1, p2... */
  luaL_argcheck(L, n_arg >= 2, 2, "value expected");
  lua_pushvalue(L, 1);  /* f to top */
  lua_pushvalue(L, 2);  /* msgh to top */
  lua_replace(L, 1); /* msgh to 1 */
  lua_replace(L, 2); /* f to 2 */
  /* msgh, f, p1, p2... */
  ret = lua_pcall(L, n_arg - 2, LUA_MULTRET, 1);
  lua_pushboolean(L, ret == 0);
  lua_replace(L, 1);
  return lua_gettop(L);
}

int luaopen_util_compat(lua_State *L) {
	lua_createtable(L, 0, 2);
	{
		lua_pushcfunction(L, lc_xpcall);
		lua_setfield(L, -2, "xpcall");
	}
	return 1;
}