patch 8.0.0592: if a job writes to a buffer screen is not updated

Problem:    If a job writes to a buffer and the user is typing a command, the
            screen isn't updated. When a message is displayed the changed
            buffer may cause it to be cleared. (Ramel Eshed)
Solution:   Update the screen and then the command line if the screen didn't
            scroll. Avoid inserting screen lines, as it clears any message.
            Update the status line when the buffer changed.

Author: brammool

src/channel.c

@@ -2404,7 +2404,7 @@ append_to_buffer(buf_T *buffer, char_u *msg, channel_T *channel, ch_part_T part)
 		curbuf = curwin->w_buffer;
 	    }
 	}
-	redraw_buf_later(buffer, VALID);
+	redraw_buf_and_status_later(buffer, VALID);
 	channel_need_redraw = TRUE;
     }
 

src/ex_getln.c

@@ -3336,11 +3336,18 @@ cmdline_del(int from)
  */
     void
 redrawcmdline(void)
+{
+    redrawcmdline_ex(TRUE);
+}
+
+    void
+redrawcmdline_ex(int do_compute_cmdrow)
 {
     if (cmd_silent)
 	return;
     need_wait_return = FALSE;
-    compute_cmdrow();
+    if (do_compute_cmdrow)
+	compute_cmdrow();
     redrawcmd();
     cursorcmd();
 }

src/globals.h

@@ -97,6 +97,7 @@ EXTERN int	cmdline_row;
 EXTERN int	redraw_cmdline INIT(= FALSE);	/* cmdline must be redrawn */
 EXTERN int	clear_cmdline INIT(= FALSE);	/* cmdline must be cleared */
 EXTERN int	mode_displayed INIT(= FALSE);	/* mode is being displayed */
+EXTERN int	no_win_do_lines_ins INIT(= FALSE); /* don't insert lines */
 #if defined(FEAT_CRYPT) || defined(FEAT_EVAL)
 EXTERN int	cmdline_star INIT(= FALSE);	/* cmdline is crypted */
 #endif

src/proto/ex_getln.pro

@@ -19,6 +19,7 @@ char_u *save_cmdline_alloc(void);
 void restore_cmdline_alloc(char_u *p);
 void cmdline_paste_str(char_u *s, int literally);
 void redrawcmdline(void);
+void redrawcmdline_ex(int do_compute_cmdrow);
 void redrawcmd(void);
 void compute_cmdrow(void);
 void gotocmdline(int clr);

src/proto/screen.pro

@@ -5,11 +5,12 @@ void redraw_later_clear(void);
 void redraw_all_later(int type);
 void redraw_curbuf_later(int type);
 void redraw_buf_later(buf_T *buf, int type);
+void redraw_buf_and_status_later(buf_T *buf, int type);
 int redraw_asap(int type);
 void redraw_after_callback(void);
 void redrawWinline(linenr_T lnum, int invalid);
 void update_curbuf(int type);
-void update_screen(int type);
+void update_screen(int type_arg);
 int conceal_cursor_line(win_T *wp);
 void conceal_check_cursur_line(void);
 void update_single_line(win_T *wp, linenr_T lnum);

src/screen.c

@@ -265,6 +265,21 @@ redraw_buf_later(buf_T *buf, int type)
     }
 }
 
+    void
+redraw_buf_and_status_later(buf_T *buf, int type)
+{
+    win_T	*wp;
+
+    FOR_ALL_WINDOWS(wp)
+    {
+	if (wp->w_buffer == buf)
+	{
+	    redraw_win_later(wp, type);
+	    wp->w_redr_status = TRUE;
+	}
+    }
+}
+
 /*
  * Redraw as soon as possible.  When the command line is not scrolled redraw
  * right away and restore what was on the command line.
@@ -421,10 +436,29 @@ redraw_after_callback(void)
     if (State == HITRETURN || State == ASKMORE)
 	; /* do nothing */
     else if (State & CMDLINE)
-	redrawcmdline();
+    {
+	/* Redrawing only works when the screen didn't scroll. */
+	if (msg_scrolled == 0)
+	{
+	    update_screen(0);
+	    compute_cmdrow();
+	}
+	else
+	{
+	    /* Redraw in the same position, so that the user can continue
+	     * editing the command. */
+	    compute_cmdrow();
+	    if (cmdline_row > msg_scrolled)
+		cmdline_row -= msg_scrolled;
+	    else
+		cmdline_row = 0;
+	}
+	redrawcmdline_ex(FALSE);
+    }
     else if (State & (NORMAL | INSERT))
     {
-	update_screen(0);
+	/* keep the command line if possible */
+	update_screen(VALID_NO_UPDATE);
 	setcursor();
     }
     cursor_on();
@@ -476,7 +510,7 @@ redrawWinline(
 }
 
 /*
- * update all windows that are editing the current buffer
+ * Update all windows that are editing the current buffer.
  */
     void
 update_curbuf(int type)
@@ -490,8 +524,9 @@ update_curbuf(int type)
  * of stuff from Filemem to ScreenLines[], and update curwin->w_botline.
  */
     void
-update_screen(int type)
+update_screen(int type_arg)
 {
+    int		type = type_arg;
     win_T	*wp;
     static int	did_intro = FALSE;
 #if defined(FEAT_SEARCH_EXTRA) || defined(FEAT_CLIPBOARD)
@@ -502,11 +537,18 @@ update_screen(int type)
     int		gui_cursor_col;
     int		gui_cursor_row;
 #endif
+    int		no_update = FALSE;
 
     /* Don't do anything if the screen structures are (not yet) valid. */
     if (!screen_valid(TRUE))
 	return;
 
+    if (type == VALID_NO_UPDATE)
+    {
+	no_update = TRUE;
+	type = 0;
+    }
+
     if (must_redraw)
     {
 	if (type < must_redraw)	    /* use maximal type */
@@ -539,6 +581,8 @@ update_screen(int type)
     ++display_tick;	    /* let syntax code know we're in a next round of
 			     * display updating */
 #endif
+    if (no_update)
+	++no_win_do_lines_ins;
 
     /*
      * if the screen was scrolled up when displaying a message, scroll it down
@@ -576,7 +620,8 @@ update_screen(int type)
 		    }
 		}
 	    }
-	    redraw_cmdline = TRUE;
+	    if (!no_update)
+		redraw_cmdline = TRUE;
 #ifdef FEAT_WINDOWS
 	    redraw_tabline = TRUE;
 #endif
@@ -748,6 +793,9 @@ update_screen(int type)
     if (clear_cmdline || redraw_cmdline)
 	showmode();
 
+    if (no_update)
+	--no_win_do_lines_ins;
+
     /* May put up an introductory message when not editing a file */
     if (!did_intro)
 	maybe_intro_message();
@@ -9475,14 +9523,20 @@ win_do_lines(
     if (!redrawing() || line_count <= 0)
 	return FAIL;
 
+    /* When inserting lines would result in loss of command output, just redraw
+     * the lines. */
+    if (no_win_do_lines_ins && !del)
+	return FAIL;
+
     /* only a few lines left: redraw is faster */
     if (mayclear && Rows - line_count < 5
 #ifdef FEAT_WINDOWS
 	    && wp->w_width == Columns
 #endif
 	    )
     {
-	screenclear();	    /* will set wp->w_lines_valid to 0 */
+	if (!no_win_do_lines_ins)
+	    screenclear();	    /* will set wp->w_lines_valid to 0 */
 	return FAIL;
     }
 
@@ -9498,10 +9552,12 @@ win_do_lines(
     }
 
     /*
-     * when scrolling, the message on the command line should be cleared,
+     * When scrolling, the message on the command line should be cleared,
      * otherwise it will stay there forever.
+     * Don't do this when avoiding to insert lines.
      */
-    clear_cmdline = TRUE;
+    if (!no_win_do_lines_ins)
+	clear_cmdline = TRUE;
 
     /*
      * If the terminal can set a scroll region, use that.

src/version.c

@@ -764,6 +764,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    592,
 /**/
     591,
 /**/

src/vim.h

@@ -630,6 +630,8 @@ extern int (*dyn_libintl_putenv)(const char *envstring);
  * flags for update_screen()
  * The higher the value, the higher the priority
  */
+#define VALID_NO_UPDATE		 5  /* no new changes, keep the command line if
+				       possible */
 #define VALID			10  /* buffer not changed, or changes marked
 				       with b_mod_* */
 #define INVERTED		20  /* redisplay inverted part that changed */