Commit: patch 9.2.0160: terminal DEC mode handling is overly complex

[Christian Brabandt]

patch 9.2.0160: terminal DEC mode handling is overly complex

Commit: https://github.com/vim/vim/commit/13b25e2f34dfa32d44c6fa330f39bbe1c2deb273
Author: Foxe Chen <chen...@gmail.com>
Date: Fri Mar 13 21:55:16 2026 +0000

patch 9.2.0160: terminal DEC mode handling is overly complex

Problem: terminal DEC mode handling is overly complex (after v9.2.0139)
Solution: Refactor DEC mode handling (Foxe Chen).

related: #19596
related: #19541
closes: #19641

Signed-off-by: Foxe Chen <chen...@gmail.com>
Signed-off-by: Christian Brabandt <c...@256bit.org>

diff --git a/runtime/doc/options.txt b/runtime/doc/options.txt
index 3542eb345..245089a3b 100644
--- a/runtime/doc/options.txt
+++ b/runtime/doc/options.txt
@@ -1,4 +1,4 @@
-*options.txt* For Vim version 9.2. Last change: 2026 Mar 12
+*options.txt* For Vim version 9.2. Last change: 2026 Mar 13


VIM REFERENCE MANUAL by Bram Moolenaar
@@ -9144,10 +9144,7 @@ A jump table for the options with a short description can be found at |Q_op|.
The specification can be found at:
https://github.com/contour-terminal/vt-extensions/blob/master/synchronized-output.md

- Vim may set this option automatically at startup time when Vim is
- compiled with the |+termresponse| feature, by querying the terminal
- for DEC mode 2026 support. The terminal codes used are |t_BS| and
- |t_ES|.
+ The terminal codes used are |t_BS| and |t_ES|.

*'termwinkey'* *'twk'*
'termwinkey' 'twk' string (default "")
diff --git a/src/main.c b/src/main.c
index 4579690e1..9f9fd1205 100644
--- a/src/main.c
+++ b/src/main.c
@@ -892,8 +892,6 @@ vim_main2(void)
may_req_termresponse();

may_req_bg_color();
-
- may_req_dec_setting();
# endif

// start in insert mode
diff --git a/src/proto/term.pro b/src/proto/term.pro
index 80f9b00e9..9653a35af 100644
--- a/src/proto/term.pro
+++ b/src/proto/term.pro
@@ -96,7 +96,6 @@ void swap_tcap(void);
void ansi_color2rgb(int nr, char_u *r, char_u *g, char_u *b, char_u *ansi_idx);
void cterm_color2rgb(int nr, char_u *r, char_u *g, char_u *b, char_u *ansi_idx);
int term_replace_keycodes(char_u *ta_buf, int ta_len, int len_arg);
-void may_req_dec_setting(void);
void term_disable_dec(void);
void term_set_win_resize(bool state);
void term_set_sync_output(int flags);
diff --git a/src/term.c b/src/term.c
index 8b557ae99..a1bb6c1b9 100644
--- a/src/term.c
+++ b/src/term.c
@@ -130,14 +130,6 @@ static termrequest_T u7_status = TERMREQUEST_INIT;
// Request xterm compatibility check:
static termrequest_T xcc_status = TERMREQUEST_INIT;

-// Request synchronized output report
-static termrequest_T sync_output_status = TERMREQUEST_INIT;
-
-#ifdef UNIX
-// Request in-band window resize events report
-static termrequest_T win_resize_status = TERMREQUEST_INIT;
-#endif
-
#ifdef FEAT_TERMRESPONSE
# ifdef FEAT_TERMINAL
// Request foreground color report:
@@ -173,10 +165,6 @@ static termrequest_T *all_termrequests[] = {
&rbm_status,
&rcs_status,
&winpos_status,
- &sync_output_status,
-# ifdef UNIX
- &win_resize_status,
-# endif
NULL
};

@@ -687,6 +675,25 @@ static tcap_entry_T builtin_kitty[] = {
{(int)KS_NAME, NULL} // end marker
};

+/*
+ * Additions for enabling/disabling synchronized output mode for terminal.
+ */
+static tcap_entry_T builtin_sync_output[] = {
+ {(int)KS_BSU, " [?2026h"},
+ {(int)KS_ESU, " [?2026l"},
+ {(int)KS_NAME, NULL} // end marker
+};
+
+/*
+ * List of DECRQM modes that Vim supports
+ */
+static int dec_modes[] = {
+ 2026, // Synchronized output
+#ifdef UNIX
+ 2048 // In-band terminal resize events
+#endif
+};
+
#ifdef FEAT_TERMGUICOLORS
/*
* Additions for using the RGB colors and terminal font
@@ -2202,6 +2209,8 @@ set_termname(char_u *term)
#ifdef HAVE_TGETENT
if (term_strings_not_set(KS_CF))
apply_builtin_tcap(term, special_term, TRUE);
+ if (term_strings_not_set(KS_BSU) && term_strings_not_set(KS_ESU))
+ apply_builtin_tcap(term, builtin_sync_output, TRUE);
#endif
}

@@ -2222,14 +2231,6 @@ set_termname(char_u *term)
&& (T_CRV == NULL || *T_CRV == NUL))
T_CRV = (char_u *)" [>c";

- // These are the DECSET/DECRESET codes for synchronized output. iTerm
- // supports another way, but this is the de facto standard terminal codes
- // that are used (from what I can tell - 64bitman).
- if (T_BSU == NULL || T_BSU == empty_option)
- T_BSU = (char_u *)" [?2026h";
- if (T_ESU == NULL || T_ESU == empty_option)
- T_ESU = (char_u *)" [?2026l";
-
#ifdef UNIX
/*
* Any "stty" settings override the default for t_kb from the termcap.
@@ -4048,6 +4049,13 @@ starttermcap(void)
out_str(T_FE);
#endif

+ // Request setting of relevant DEC modes via DECRQM
+ for (int i = 0; i < (int)ARRAY_LENGTH(dec_modes); i++)
+ {
+ vim_snprintf((char *)IObuff, IOSIZE, " [?%d$p", dec_modes[i]);
+ out_str(IObuff);
+ }
+
out_flush();
termcap_active = TRUE;
screen_start(); // don't know where cursor is now
@@ -5757,13 +5765,11 @@ handle_csi(
{
case 2026:
sync_output_setting = setting;
- sync_output_status.tr_progress = STATUS_GOT;
set_option_value_give_err((char_u *)"termsync",
setting == 1 || setting == 2, NULL, 0);
break;
#ifdef UNIX
case 2048:
- win_resize_status.tr_progress = STATUS_GOT;
win_resize_setting = setting;

term_set_win_resize(true);
@@ -7896,52 +7902,6 @@ term_replace_keycodes(char_u *ta_buf, int ta_len, int len_arg)
return len;
}

-#ifdef FEAT_TERMRESPONSE
-/*
- * Query the setting for the following DEC modes from the terminal:
- * - DEC mode 2026 (synchronized output)
- * - DEC mode 2048 (window resize events)
- */
- void
-may_req_dec_setting(void)
-{
- if (can_get_termresponse() && starting == 0)
- {
- bool didit = false;
-
- if (sync_output_status.tr_progress == STATUS_GET)
- {
- MAY_WANT_TO_LOG_THIS;
- LOG_TR1("Sending synchronized output request");
-
- out_str((char_u *)" [?2026$p");
- termrequest_sent(&sync_output_status);
- didit = true;
- }
-
-# ifdef UNIX
- if (win_resize_status.tr_progress == STATUS_GET)
- {
- MAY_WANT_TO_LOG_THIS;
- LOG_TR1("Sending in-band window resize events request");
-
- out_str((char_u *)" [?2048$p");
- termrequest_sent(&win_resize_status);
- didit = true;
- }
-# endif
-
- if (didit)
- {
- // check for the characters now, otherwise they might be eaten by
- // get_keystroke()
- out_flush();
- (void)vpeekc_nomap();
- }
- }
-}
-#endif
-
/*
* Should be called when cleaning up terminal state.
*/
diff --git a/src/version.c b/src/version.c
index a55c7a1ab..c0f5c7488 100644
--- a/src/version.c
+++ b/src/version.c
@@ -734,6 +734,8 @@ static char *(features[]) =

static int included_patches[] =
{ /* Add new patch number below this line */
+/**/
+ 160,
/**/
159,
/**/