Commit: patch 9.2.0651: completion: 'smartcase' doesn't work with 'longest'

[Christian Brabandt]

patch 9.2.0651: completion: 'smartcase' doesn't work with 'longest'

Commit: https://github.com/vim/vim/commit/50fe45aca72af15952131241067c8e3a5bf71d23
Author: glepnir <gleph...@gmail.com>
Date: Mon Jun 15 18:49:47 2026 +0000

patch 9.2.0651: completion: 'smartcase' doesn't work with 'longest'

Problem: With 'longest', 'smartcase' is ignored when filtering matches:
"inp" offers only "InputEvent", and an uppercase pattern gives
different results for CTRL-N and CTRL-P.
Solution: 'longest' rewrites the leader with the common prefix, picking
up uppercase the user never typed. Judge case from the typed
text instead, and match the auto-inserted part of the leader
case-insensitively so CTRL-N and CTRL-P give the same result.
(glepnir)

related: neovim/neovim#40259
closes: #20533

Signed-off-by: glepnir <gleph...@gmail.com>
Signed-off-by: Christian Brabandt <c...@256bit.org>

diff --git a/src/insexpand.c b/src/insexpand.c
index c63b49c7f..a355e2949 100644
--- a/src/insexpand.c
+++ b/src/insexpand.c
@@ -187,6 +187,7 @@ static linenr_T compl_lnum = 0; // lnum where the completion start
static colnr_T compl_col = 0; // column where the text starts
// that is being completed
static colnr_T compl_ins_end_col = 0;
+static colnr_T compl_longest_end_col = 0; // end of 'longest' inserted text
static string_T compl_orig_text = {NULL, 0}; // text as it was before
// completion started
static int compl_cont_mode = 0;
@@ -1051,6 +1052,33 @@ ins_compl_equal(compl_T *match, char_u *str, int len)
return STRNCMP(match->cp_str.string, str, (size_t)len) == 0;
}

+/*
+ * Like ins_compl_equal(), but ignore case in the 'longest'-inserted part of
+ * the leader, so CTRL-N and CTRL-P filter the same way.
+ */
+ static int
+ins_compl_equal_sc(compl_T *match, char_u *str, int len)
+{
+ int typed = compl_length;
+ int longest_end = (compl_get_longest && compl_longest_end_col > compl_col)
+ ? (int)(compl_longest_end_col - compl_col) : typed;
+
+ if ((match->cp_flags & (CP_EQUAL | CP_ICASE)) || longest_end <= typed)
+ return ins_compl_equal(match, str, len);
+
+ if ((int)match->cp_str.length < len)
+ return FALSE;
+
+ for (int i = 0; i < len; ++i)
+ {
+ if (i >= typed && i < longest_end
+ ? MB_TOLOWER(match->cp_str.string[i]) != MB_TOLOWER(str[i])
+ : match->cp_str.string[i] != str[i])
+ return FALSE;
+ }
+ return TRUE;
+}
+
/*
* when len is -1 mean use whole length of p otherwise part of p
*/
@@ -1687,14 +1715,15 @@ ins_compl_build_pum(void)

leader = get_leader_for_startcol(compl, TRUE);

- // Apply 'smartcase' behavior during normal mode
- if (ctrl_x_mode_normal() && !p_inf && leader->string
- && !ignorecase(leader->string) && !cot_fuzzy())
+ // Apply 'smartcase': judge case from compl_orig_text, not the leader
+ // which 'longest' may fill with uppercase the user never typed.
+ if (ctrl_x_mode_normal() && !p_inf && compl_orig_text.string
+ && !ignorecase(compl_orig_text.string) && !cot_fuzzy())
compl->cp_flags &= ~CP_ICASE;

if (!match_at_original_text(compl)
&& (leader->string == NULL
- || ins_compl_equal(compl, leader->string,
+ || ins_compl_equal_sc(compl, leader->string,
(int)leader->length)
|| (cot_fuzzy() && compl->cp_score != FUZZY_SCORE_NONE)))
{
@@ -2285,6 +2314,7 @@ ins_compl_clear(void)
compl_matches = 0;
compl_selected_item = -1;
compl_ins_end_col = 0;
+ compl_longest_end_col = 0;
compl_curr_win = NULL;
compl_curr_buf = NULL;
VIM_CLEAR_STRING(compl_pattern);
@@ -4517,6 +4547,7 @@ ins_compl_longest_insert(char_u *prefix)
{
ins_compl_delete();
ins_compl_insert_bytes(prefix + get_compl_len(), -1);
+ compl_longest_end_col = curwin->w_cursor.col;
ins_redraw(FALSE);
}

@@ -5805,13 +5836,13 @@ find_common_prefix(size_t *prefix_len, int curbuf_only)
string_T *leader = get_leader_for_startcol(compl, TRUE);

// Apply 'smartcase' behavior during normal mode
- if (ctrl_x_mode_normal() && !p_inf && leader->string
- && !ignorecase(leader->string))
+ if (ctrl_x_mode_normal() && !p_inf && compl_orig_text.string
+ && !ignorecase(compl_orig_text.string))
compl->cp_flags &= ~CP_ICASE;

if (!match_at_original_text(compl)
&& (leader->string == NULL
- || ins_compl_equal(compl, leader->string,
+ || ins_compl_equal_sc(compl, leader->string,
(int)leader->length)))
{
// Limit number of items from each source if max_items is set.
diff --git a/src/testdir/test_ins_complete.vim b/src/testdir/test_ins_complete.vim
index c741fd1e7..aafc4a84d 100644
--- a/src/testdir/test_ins_complete.vim
+++ b/src/testdir/test_ins_complete.vim
@@ -6357,4 +6357,48 @@ func Test_mapped_ctrl_n_during_complete_function()
bwipe!
endfunc

+func Test_smartcase_longest()
+ func! GetMatches()
+ let info = complete_info(["matches"])
+ return map(copy(info.matches), {_, v -> v.word})
+ endfunc
+
+ func! TestInner(key)
+ let pr = "\<c-r>=string(GetMatches())\<cr>"
+ let words = ["InputEvent", "inputmap", "INPUT_MAP"]
+
+ new
+ set completeopt=menuone,noselect,longest ignorecase smartcase
+
+ " Lowercase 'inp' all three (case-insensitive).
+ call setline(1, words)
+ exe $"normal! ggOinp{a:key}{pr}"
+ let line = getline(1)
+ call assert_match('