vim-patch:8.2.4037: Insert mode completion is insufficiently tested

Problem:    Insert mode completion is insufficiently tested.
Solution:   Add more tests.  Fix uncovered memory leak. (Yegappan Lakshmanan,
            closes vim/vim#9489)
https://github.com/vim/vim/commit/370791465e745354d66696de8cbd15504cf958c0

2 files changed, 260 insertions, 13 deletions

diff --git a/src/nvim/insexpand.c b/src/nvim/insexpand.c
index 21285a4365..ec885b33c3 100644
--- a/src/nvim/insexpand.c
+++ b/src/nvim/insexpand.c
@@ -659,17 +659,23 @@ int ins_compl_add_infercase(char_u *str_arg, int len, bool icase, char_u *fname,
 
 /// Add a match to the list of matches
 ///
-/// @param[in]  str  Match to add.
-/// @param[in]  len  Match length, -1 to use #STRLEN.
-/// @param[in]  fname  File name match comes from. May be NULL.
-/// @param[in]  cptext  Extra text for popup menu. May be NULL. If not NULL,
-///                     must have exactly #CPT_COUNT items.
+/// @param[in]  str     text of the match to add
+/// @param[in]  len     length of "str". If -1, then the length of "str" is computed.
+/// @param[in]  fname   file name to associate with this match. May be NULL.
+/// @param[in]  cptext  list of strings to use with this match (for abbr, menu, info
+///                     and kind). May be NULL.
+///                     If not NULL, must have exactly #CPT_COUNT items.
 /// @param[in]  cptext_allocated  If true, will not copy cptext strings.
 ///
 ///                               @note Will free strings in case of error.
 ///                                     cptext itself will not be freed.
-/// @param[in]  cdir  Completion direction.
-/// @param[in]  adup  True if duplicate matches are to be accepted.
+/// @param[in]  user_data  user supplied data (any vim type) for this match
+/// @param[in]  cdir       match direction. If 0, use "compl_direction".
+/// @param[in]  flags_arg  match flags (cp_flags)
+/// @param[in]  adup       accept this match even if it is already present.
+///
+/// If "cdir" is FORWARD, then the match is added after the current match.
+/// Otherwise, it is added before the current match.
 ///
 /// @return NOTDONE if the given string is already in the list of completions,
 ///         otherwise it is added to the list and  OK is returned. FAIL will be
@@ -768,7 +774,8 @@ static int ins_compl_add(char_u *const str, int len, char_u *const fname,
     match->cp_user_data = *user_data;
   }
 
-  // Link the new match structure in the list of matches.
+  // Link the new match structure after (FORWARD) or before (BACKWARD) the
+  // current match in the list of matches .
   if (compl_first_match == NULL) {
     match->cp_next = match->cp_prev = NULL;
   } else if (dir == FORWARD) {
@@ -2265,10 +2272,15 @@ static int ins_compl_add_tv(typval_T *const tv, const Direction dir, bool fast)
     for (size_t i = 0; i < CPT_COUNT; i++) {
       xfree(cptext[i]);
     }
+    tv_clear(&user_data);
     return FAIL;
   }
-  return ins_compl_add((char_u *)word, -1, NULL,
-                       (char_u **)cptext, true, &user_data, dir, flags, dup);
+  int status = ins_compl_add((char_u *)word, -1, NULL, (char_u **)cptext, true,
+                             &user_data, dir, flags, dup);
+  if (status != OK) {
+    tv_clear(&user_data);
+  }
+  return status;
 }
 
 /// Add completions from a list.
@@ -2606,8 +2618,8 @@ enum {
 ///   st->dict_f - flag specifying whether "dict" is an exact file name or not
 ///
 /// @return  INS_COMPL_CPT_OK if the next value is processed successfully.
-///          INS_COMPL_CPT_CONT to skip the current value and process the next
-///          option value.
+///          INS_COMPL_CPT_CONT to skip the current completion source matching
+///          the "st->e_cpt" option value and process the next matching source.
 ///          INS_COMPL_CPT_END if all the values in "st->e_cpt" are processed.
 static int process_next_cpt_value(ins_compl_next_state_T *st, int *compl_type_arg,
                                   pos_T *start_match_pos)
@@ -3788,7 +3800,7 @@ static int get_userdefined_compl_info(colnr_T curs_col)
     return FAIL;
   }
 
-  // Reset extended parameters of completion, when start new
+  // Reset extended parameters of completion, when starting new
   // completion.
   compl_opt_refresh_always = false;
 
diff --git a/src/nvim/testdir/test_ins_complete.vim b/src/nvim/testdir/test_ins_complete.vim
index 914d818eef..3e563f29f9 100644
--- a/src/nvim/testdir/test_ins_complete.vim
+++ b/src/nvim/testdir/test_ins_complete.vim
@@ -68,6 +68,11 @@ func Test_ins_complete()
   call assert_equal('Xtest11.one', getline('.'))
   normal ddk
 
+  " Test for expanding a non-existing filename
+  exe "normal oa1b2X3Y4\<C-X>\<C-F>"
+  call assert_equal('a1b2X3Y4', getline('.'))
+  normal ddk
+
   set cpt=w
   " checks make_cyclic in other window
   exe "normal oST\<C-N>\<C-P>\<C-P>\<C-P>\<C-P>"
@@ -955,6 +960,27 @@ func Test_complete_erase_firstmatch()
   bw!
 endfunc
 
+" Test for completing words from unloaded buffers
+func Test_complete_from_unloadedbuf()
+  call writefile(['abc'], "Xfile1")
+  call writefile(['def'], "Xfile2")
+  edit Xfile1
+  edit Xfile2
+  new | close
+  enew
+  bunload Xfile1 Xfile2
+  set complete=u
+  " complete from an unloaded buffer
+  exe "normal! ia\<C-P>"
+  call assert_equal('abc', getline(1))
+  exe "normal! od\<C-P>"
+  call assert_equal('def', getline(2))
+  set complete&
+  %bw!
+  call delete("Xfile1")
+  call delete("Xfile2")
+endfunc
+
 " Test for completing whole lines from unloaded buffers
 func Test_complete_wholeline_unloadedbuf()
   call writefile(['a line1', 'a line2', 'a line3'], "Xfile1")
@@ -973,6 +999,26 @@ func Test_complete_wholeline_unloadedbuf()
   call delete("Xfile1")
 endfunc
 
+" Test for completing words from unlisted buffers
+func Test_complete_from_unlistedbuf()
+  call writefile(['abc'], "Xfile1")
+  call writefile(['def'], "Xfile2")
+  edit Xfile1
+  edit Xfile2
+  new | close
+  bdel Xfile1 Xfile2
+  set complete=U
+  " complete from an unlisted buffer
+  exe "normal! ia\<C-P>"
+  call assert_equal('abc', getline(1))
+  exe "normal! od\<C-P>"
+  call assert_equal('def', getline(2))
+  set complete&
+  %bw!
+  call delete("Xfile1")
+  call delete("Xfile2")
+endfunc
+
 " Test for completing whole lines from unlisted buffers
 func Test_complete_wholeline_unlistedbuf()
   call writefile(['a line1', 'a line2', 'a line3'], "Xfile1")
@@ -1006,6 +1052,195 @@ func Test_complete_mbyte_char_add()
   bw!
 endfunc
 
+" Test for using <C-X><C-P> for local expansion even if 'complete' is set to
+" not to complete matches from the local buffer. Also test using multiple
+" <C-X> to cancel the current completion mode.
+func Test_complete_local_expansion()
+  new
+  set complete=t
+  call setline(1, ['abc', 'def'])
+  exe "normal! Go\<C-X>\<C-P>"
+  call assert_equal("def", getline(3))
+  exe "normal! Go\<C-P>"
+  call assert_equal("", getline(4))
+  exe "normal! Go\<C-X>\<C-N>"
+  call assert_equal("abc", getline(5))
+  exe "normal! Go\<C-N>"
+  call assert_equal("", getline(6))
+
+  " use multiple <C-X> to cancel the previous completion mode
+  exe "normal! Go\<C-P>\<C-X>\<C-P>"
+  call assert_equal("", getline(7))
+  exe "normal! Go\<C-P>\<C-X>\<C-X>\<C-P>"
+  call assert_equal("", getline(8))
+  exe "normal! Go\<C-P>\<C-X>\<C-X>\<C-X>\<C-P>"
+  call assert_equal("abc", getline(9))
+
+  " interrupt the current completion mode
+  set completeopt=menu,noinsert
+  exe "normal! Go\<C-X>\<C-F>\<C-X>\<C-X>\<C-P>\<C-Y>"
+  call assert_equal("abc", getline(10))
+
+  " when only one <C-X> is used to interrupt, do normal expansion
+  exe "normal! Go\<C-X>\<C-F>\<C-X>\<C-P>"
+  call assert_equal("", getline(11))
+  set completeopt&
+
+  " using two <C-X> in non-completion mode and restarting the same mode
+  exe "normal! God\<C-X>\<C-X>\<C-P>\<C-X>\<C-X>\<C-P>\<C-Y>"
+  call assert_equal("def", getline(12))
+
+  " test for adding a match from the original empty text
+  %d
+  call setline(1, 'abc def g')
+  exe "normal! o\<C-X>\<C-P>\<C-N>\<C-X>\<C-P>"
+  call assert_equal('def', getline(2))
+  exe "normal! 0C\<C-X>\<C-N>\<C-P>\<C-X>\<C-N>"
+  call assert_equal('abc', getline(2))
+
+  bw!
+endfunc
+
+" Test for undoing changes after a insert-mode completion
+func Test_complete_undo()
+  new
+  set complete=.
+  " undo with 'ignorecase'
+  call setline(1, ['ABOVE', 'BELOW'])
+  set ignorecase
+  exe "normal! Goab\<C-G>u\<C-P>"
+  call assert_equal("ABOVE", getline(3))
+  undo
+  call assert_equal("ab", getline(3))
+  set ignorecase&
+  %d
+  " undo with longest match
+  set completeopt=menu,longest
+  call setline(1, ['above', 'about'])
+  exe "normal! Goa\<C-G>u\<C-P>"
+  call assert_equal("abo", getline(3))
+  undo
+  call assert_equal("a", getline(3))
+  set completeopt&
+  %d
+  " undo for line completion
+  call setline(1, ['above that change', 'below that change'])
+  exe "normal! Goabove\<C-G>u\<C-X>\<C-L>"
+  call assert_equal("above that change", getline(3))
+  undo
+  call assert_equal("above", getline(3))
+
+  bw!
+endfunc
+
+" Test for completing a very long word
+func Test_complete_long_word()
+  set complete&
+  new
+  call setline(1, repeat('x', 950) .. ' one two three')
+  exe "normal! Gox\<C-X>\<C-P>\<C-X>\<C-P>\<C-X>\<C-P>\<C-X>\<C-P>"
+  call assert_equal(repeat('x', 950) .. ' one two three', getline(2))
+  %d
+  " should fail when more than 950 characters are in a word
+  call setline(1, repeat('x', 951) .. ' one two three')
+  exe "normal! Gox\<C-X>\<C-P>\<C-X>\<C-P>\<C-X>\<C-P>\<C-X>\<C-P>"
+  call assert_equal(repeat('x', 951), getline(2))
+
+  " Test for adding a very long word to an existing completion
+  %d
+  call setline(1, ['abc', repeat('x', 1016) .. '012345'])
+  exe "normal! Goab\<C-P>\<C-X>\<C-P>"
+  call assert_equal('abc ' .. repeat('x', 1016) .. '0123', getline(3))
+  bw!
+endfunc
+
+" Test for some fields in the complete items used by complete()
+func Test_complete_items()
+  func CompleteItems(idx)
+    let items = [[#{word: "one", dup: 1, user_data: 'u1'}, #{word: "one", dup: 1, user_data: 'u2'}],
+          \ [#{word: "one", dup: 0, user_data: 'u3'}, #{word: "one", dup: 0, user_data: 'u4'}],
+          \ [#{word: "one", icase: 1, user_data: 'u7'}, #{word: "oNE", icase: 1, user_data: 'u8'}],
+          \ [#{user_data: 'u9'}],
+          \ [#{word: "", user_data: 'u10'}],
+          \ [#{word: "", empty: 1, user_data: 'u11'}]]
+    call complete(col('.'), items[a:idx])
+    return ''
+  endfunc
+  new
+  exe "normal! i\<C-R>=CompleteItems(0)\<CR>\<C-N>\<C-Y>"
+  call assert_equal('u2', v:completed_item.user_data)
+  call assert_equal('one', getline(1))
+  exe "normal! o\<C-R>=CompleteItems(1)\<CR>\<C-Y>"
+  call assert_equal('u3', v:completed_item.user_data)
+  call assert_equal('one', getline(2))
+  exe "normal! o\<C-R>=CompleteItems(1)\<CR>\<C-N>"
+  call assert_equal('', getline(3))
+  set completeopt=menu,noinsert
+  exe "normal! o\<C-R>=CompleteItems(2)\<CR>one\<C-N>\<C-Y>"
+  call assert_equal('oNE', getline(4))
+  call assert_equal('u8', v:completed_item.user_data)
+  set completeopt&
+  exe "normal! o\<C-R>=CompleteItems(3)\<CR>"
+  call assert_equal('', getline(5))
+  exe "normal! o\<C-R>=CompleteItems(4)\<CR>"
+  call assert_equal('', getline(6))
+  exe "normal! o\<C-R>=CompleteItems(5)\<CR>"
+  call assert_equal('', getline(7))
+  call assert_equal('u11', v:completed_item.user_data)
+  " pass invalid argument to complete()
+  let cmd = "normal! o\<C-R>=complete(1, [[]])\<CR>"
+  call assert_fails('exe cmd', 'E730:')
+  bw!
+  delfunc CompleteItems
+endfunc
+
+" Test for the "refresh" item in the dict returned by an insert completion
+" function
+func Test_complete_item_refresh_always()
+  let g:CallCount = 0
+  func! Tcomplete(findstart, base)
+    if a:findstart
+      " locate the start of the word
+      let line = getline('.')
+      let start = col('.') - 1
+      while start > 0 && line[start - 1] =~ '\a'
+        let start -= 1
+      endwhile
+      return start
+    else
+      let g:CallCount += 1
+      let res = ["update1", "update12", "update123"]
+      return #{words: res, refresh: 'always'}
+    endif
+  endfunc
+  new
+  set completeopt=menu,longest
+  set completefunc=Tcomplete
+  exe "normal! iup\<C-X>\<C-U>\<BS>\<BS>\<BS>\<BS>\<BS>"
+  call assert_equal('up', getline(1))
+  call assert_equal(2, g:CallCount)
+  set completeopt&
+  set completefunc&
+  bw!
+  delfunc Tcomplete
+endfunc
+
+" Test for completing from a thesaurus file without read permission
+func Test_complete_unreadable_thesaurus_file()
+  CheckUnix
+  CheckNotRoot
+
+  call writefile(['about', 'above'], 'Xfile')
+  call setfperm('Xfile', '---r--r--')
+  new
+  set complete=sXfile
+  exe "normal! ia\<C-P>"
+  call assert_equal('a', getline(1))
+  bw!
+  call delete('Xfile')
+  set complete&
+endfunc
+
 " Test to ensure 'Scanning...' messages are not recorded in messages history
 func Test_z1_complete_no_history()
   new