fix(lua): don't include text after cursor in completion pattern (#29587)

1 files changed, 7 insertions, 4 deletions

diff --git a/src/nvim/lua/executor.c b/src/nvim/lua/executor.c
index bac6f4ca9a..c29e670c33 100644
--- a/src/nvim/lua/executor.c
+++ b/src/nvim/lua/executor.c
@@ -1928,7 +1928,7 @@ static garray_T expand_result_array = GA_EMPTY_INIT_VALUE;
 
 /// Finds matches for Lua cmdline completion and advances xp->xp_pattern after prefix.
 /// This should be called before xp->xp_pattern is first used.
-void nlua_expand_pat(expand_T *xp, const char *pat)
+void nlua_expand_pat(expand_T *xp)
 {
   lua_State *const lstate = global_lstate;
   int status = FAIL;
@@ -1941,7 +1941,10 @@ void nlua_expand_pat(expand_T *xp, const char *pat)
   luaL_checktype(lstate, -1, LUA_TFUNCTION);
 
   // [ vim, vim._expand_pat, pat ]
-  lua_pushstring(lstate, pat);
+  const char *pat = xp->xp_pattern;
+  assert(xp->xp_line + xp->xp_col >= pat);
+  ptrdiff_t patlen = xp->xp_line + xp->xp_col - pat;
+  lua_pushlstring(lstate, pat, (size_t)patlen);
 
   if (nlua_pcall(lstate, 1, 2) != 0) {
     nlua_error(lstate, _("Error executing vim._expand_pat: %.*s"));
@@ -1951,8 +1954,8 @@ void nlua_expand_pat(expand_T *xp, const char *pat)
   Error err = ERROR_INIT;
 
   Arena arena = ARENA_EMPTY;
-  int prefix_len = (int)nlua_pop_Integer(lstate, &arena, &err);
-  if (ERROR_SET(&err)) {
+  ptrdiff_t prefix_len = nlua_pop_Integer(lstate, &arena, &err);
+  if (ERROR_SET(&err) || prefix_len > patlen) {
     goto cleanup;
   }