Don't show entire context when completing

src/nvim/ex_docmd.c

@@ -3682,7 +3682,6 @@ const char * set_one_cmd_context(
 
   case CMD_lua:
     xp->xp_context = EXPAND_LUA;
-    xp->xp_pattern = (char_u *)arg;
     break;
 
   default:

src/nvim/ex_getln.c

@@ -3946,6 +3946,12 @@ nextwild (
     p2 = ExpandOne(xp, p1, vim_strnsave(&ccline.cmdbuff[i], xp->xp_pattern_len),
                    use_options, type);
     xfree(p1);
+
+    // xp->xp_pattern might have been modified by ExpandOne (for example,
+    // in lua completion), so recompute the pattern index and length
+    i = (int)(xp->xp_pattern - ccline.cmdbuff);
+    xp->xp_pattern_len = (size_t)ccline.cmdpos - (size_t)i;
+
     // Longest match: make sure it is not shorter, happens with :help.
     if (p2 != NULL && type == WILD_LONGEST) {
       for (j = 0; (size_t)j < xp->xp_pattern_len; j++) {
@@ -3961,7 +3967,7 @@ nextwild (
   }
 
   if (p2 != NULL && !got_int) {
-    difflen = (int)STRLEN(p2) - (int)xp->xp_pattern_len;
+    difflen = (int)STRLEN(p2) - (int)(xp->xp_pattern_len);
     if (ccline.cmdlen + difflen + 4 > ccline.cmdbufflen) {
       realloc_cmdbuff(ccline.cmdlen + difflen + 4);
       xp->xp_pattern = ccline.cmdbuff + i;
@@ -5109,7 +5115,7 @@ ExpandFromContext (
   }
   if (xp->xp_context == EXPAND_LUA) {
     ILOG("PAT %s", pat);
-    return nlua_expand_pat(pat, num_file, file);
+    return nlua_expand_pat(xp, pat, num_file, file);
   }
 
   regmatch.regprog = vim_regcomp(pat, p_magic ? RE_MAGIC : 0);

src/nvim/lua/executor.c

@@ -1292,7 +1292,7 @@ static void nlua_add_treesitter(lua_State *const lstate) FUNC_ATTR_NONNULL_ALL
   lua_setfield(lstate, -2, "_ts_parse_query");
 }
 
-int nlua_expand_pat(char_u *pat, int *num_results, char_u ***results)
+int nlua_expand_pat(expand_T *xp, char_u *pat, int *num_results, char_u ***results)
 {
   lua_State *const lstate = nlua_enter();
   int ret = OK;
@@ -1307,10 +1307,11 @@ int nlua_expand_pat(char_u *pat, int *num_results, char_u ***results)
   // [ vim, vim._log_keystroke, buf ]
   lua_pushlstring(lstate, (const char *)pat, STRLEN(pat));
 
-  if (lua_pcall(lstate, 1, 1, 0)) {
+  if (lua_pcall(lstate, 1, 2, 0) != 0) {
     nlua_error(
         lstate,
         _("Error executing vim._expand_pat: %.*s"));
+    return FAIL;
   }
 
   Error err = ERROR_INIT;
@@ -1318,12 +1319,18 @@ int nlua_expand_pat(char_u *pat, int *num_results, char_u ***results)
   *num_results = 0;
   *results = NULL;
 
-  Array completions = nlua_pop_Array(lstate, &err);
+  int prefix_len = (int)nlua_pop_Integer(lstate, &err);
   if (ERROR_SET(&err)) {
     ret = FAIL;
     goto cleanup;
   }
 
+  Array completions = nlua_pop_Array(lstate, &err);
+  if (ERROR_SET(&err)) {
+    ret = FAIL;
+    goto cleanup_array;
+  }
+
   garray_T result_array;
   ga_init(&result_array, (int)sizeof(char *), 80);
   for (size_t i = 0; i < completions.size; i++) {
@@ -1331,7 +1338,7 @@ int nlua_expand_pat(char_u *pat, int *num_results, char_u ***results)
 
     if (v.type != kObjectTypeString) {
       ret = FAIL;
-      goto cleanup;
+      goto cleanup_array;
     }
 
     GA_APPEND(
@@ -1340,12 +1347,15 @@ int nlua_expand_pat(char_u *pat, int *num_results, char_u ***results)
         vim_strsave((char_u *)v.data.string.data));
   }
 
+  xp->xp_pattern += prefix_len;
   *results = result_array.ga_data;
   *num_results = result_array.ga_len;
 
-cleanup:
+cleanup_array:
   api_free_array(completions);
 
+cleanup:
+
   if (ret == FAIL) {
     ga_clear(&result_array);
   }

src/nvim/lua/vim.lua

@@ -547,7 +547,7 @@ function vim._expand_pat(pat, env)
   if pat == '' then
     local result = vim.tbl_keys(env)
     table.sort(result)
-    return result
+    return result, 0
   end
 
   -- TODO: We can handle spaces in [] ONLY.
@@ -558,7 +558,7 @@ function vim._expand_pat(pat, env)
 
   -- Get the last part of the pattern
   local last_part = pat:match("[%w.:_%[%]'\"]+$")
-  if not last_part then return {} end
+  if not last_part then return {}, 0 end
 
   local parts, search_index = vim._expand_pat_get_parts(last_part)
 
@@ -568,7 +568,7 @@ function vim._expand_pat(pat, env)
   local final_env = env
   for _, part in ipairs(parts) do
     if type(final_env) ~= 'table' then
-      return {}
+      return {}, 0
     end
 
     -- Normally, we just have a string
@@ -584,32 +584,32 @@ function vim._expand_pat(pat, env)
       -- -> _G[MY_VAR] -> "api"
       local result_key = part[1]
       if not result_key then
-        return {}
+        return {}, 0
       end
 
       local result = rawget(env, result_key)
 
       if result == nil then
-        return {}
+        return {}, 0
       end
 
       final_env = rawget(final_env, result)
     end
 
     if not final_env then
-      return {}
+      return {}, 0
     end
   end
 
   local result = vim.tbl_map(function(v)
-    return prefix_match_pat .. v
+    return v
   end, vim.tbl_filter(function(name)
     return string.find(name, match_pat) ~= nil
   end, vim.tbl_keys(final_env)))
 
   table.sort(result)
 
-  return result
+  return result, #prefix_match_pat
 end
 
 vim._expand_pat_get_parts = function(lua_string)

test/functional/lua/command_line_completion_spec.lua

@@ -6,33 +6,34 @@ local funcs = helpers.funcs
 local exec_lua = helpers.exec_lua
 
 local get_completions = function(input, env)
-  return exec_lua("return vim._expand_pat(...)", '^' .. input, env)
+  return exec_lua("return {vim._expand_pat(...)}", '^' .. input, env)
 end
 
 local get_compl_parts = function(parts)
-  return funcs.luaeval("{vim._expand_pat_get_parts(_A)}", parts)
+  return exec_lua("return {vim._expand_pat_get_parts(...)}", parts)
 end
 
 before_each(clear)
 
 describe('nlua_expand_pat', function()
   it('should complete exact matches', function()
-    eq({'exact'}, get_completions('exact', { exact = true }))
+    eq({{'exact'}, 0}, get_completions('exact', { exact = true }))
   end)
 
   it('should return empty table when nothing matches', function()
-    eq({}, get_completions('foo', { bar = true }))
+    eq({{}, 0}, get_completions('foo', { bar = true }))
   end)
 
   it('should return nice completions with function call prefix', function()
-    eq({'print(FOO'}, get_completions('print(F', { FOO = true, bawr = true }))
+    eq({{'FOO'}, 6}, get_completions('print(F', { FOO = true, bawr = true }))
   end)
 
   it('should return keys for nested dictionaries', function()
     eq(
-      {
-        'vim.api.nvim_buf_set_lines',
-        'vim.api.nvim_buf_set_option'
+      {{
+        'nvim_buf_set_lines',
+        'nvim_buf_set_option'
+       }, 8
       },
       get_completions('vim.api.nvim_buf_', {
         vim = {
@@ -49,9 +50,10 @@ describe('nlua_expand_pat', function()
 
   it('it should work with colons', function()
     eq(
-      {
-        'MyClass:bawr',
-        'MyClass:baz',
+      {{
+        'bawr',
+        'baz',
+       }, 8
       },
       get_completions('MyClass:b', {
         MyClass = {
@@ -65,9 +67,10 @@ describe('nlua_expand_pat', function()
 
   it('should return keys for string reffed dictionaries', function()
     eq(
-      {
-        'vim["api"].nvim_buf_set_lines',
-        'vim["api"].nvim_buf_set_option'
+      {{
+        'nvim_buf_set_lines',
+        'nvim_buf_set_option'
+       }, 11
       },
       get_completions('vim["api"].nvim_buf_', {
         vim = {
@@ -84,9 +87,10 @@ describe('nlua_expand_pat', function()
 
   it('should return keys for string reffed dictionaries', function()
     eq(
-      {
-        'vim["nested"]["api"].nvim_buf_set_lines',
-        'vim["nested"]["api"].nvim_buf_set_option'
+      {{
+        'nvim_buf_set_lines',
+        'nvim_buf_set_option'
+       }, 21
       },
       get_completions('vim["nested"]["api"].nvim_buf_', {
         vim = {
@@ -105,9 +109,10 @@ describe('nlua_expand_pat', function()
 
   it('should be able to interpolate globals', function()
     eq(
-      {
-        'vim[MY_VAR].nvim_buf_set_lines',
-        'vim[MY_VAR].nvim_buf_set_option'
+      {{
+        'nvim_buf_set_lines',
+        'nvim_buf_set_option'
+       }, 12
       },
       get_completions('vim[MY_VAR].nvim_buf_', {
         MY_VAR = "api",
@@ -124,7 +129,7 @@ describe('nlua_expand_pat', function()
   end)
 
   it('should return everything if the input is of length 0', function()
-    eq({"other", "vim"}, get_completions('', { vim = true, other = true }))
+    eq({{"other", "vim"}, 0}, get_completions('', { vim = true, other = true }))
   end)
 
   describe('get_parts', function()

test/functional/viml/completion_spec.lua

@@ -3,6 +3,7 @@ local Screen = require('test.functional.ui.screen')
 local clear, feed = helpers.clear, helpers.feed
 local eval, eq, neq = helpers.eval, helpers.eq, helpers.neq
 local feed_command, source, expect = helpers.feed_command, helpers.source, helpers.expect
+local funcs = helpers.funcs
 local curbufmeths = helpers.curbufmeths
 local command = helpers.command
 local meths = helpers.meths
@@ -929,10 +930,10 @@ describe('completion', function()
     end)
 
     it('provides completion from `getcompletion()`', function()
-      eq({'vim'}, meths.call_function('getcompletion', {'vi', 'lua'}))
-      eq({'vim.api'}, meths.call_function('getcompletion', {'vim.ap', 'lua'}))
-      eq({'vim.tbl_filter'}, meths.call_function('getcompletion', {'vim.tbl_fil', 'lua'}))
-      eq({'print(vim'}, meths.call_function('getcompletion', {'print(vi', 'lua'}))
+      eq({'vim'}, funcs.getcompletion('vi', 'lua'))
+      eq({'api'}, funcs.getcompletion('vim.ap', 'lua'))
+      eq({'tbl_filter'}, funcs.getcompletion('vim.tbl_fil', 'lua'))
+      eq({'vim'}, funcs.getcompletion('print(vi', 'lua'))
     end)
   end)