patch 8.1.0244: no redraw when using a STOP signal on Vim and then CONT

Problem:    No redraw when using a STOP signal on Vim and then a CONT signal.
Solution:   Catch the CONT signal and force a redraw. (closes #3285)

Author: brammool

src/os_unix.c

@@ -1227,7 +1227,23 @@ deathtrap SIGDEFARG(sigarg)
     SIGRETURN;
 }
 
-#if defined(_REENTRANT) && defined(SIGCONT)
+    static void
+after_sigcont(void)
+{
+# ifdef FEAT_TITLE
+    // Set oldtitle to NULL, so the current title is obtained again.
+    VIM_CLEAR(oldtitle);
+# endif
+    settmode(TMODE_RAW);
+    need_check_timestamps = TRUE;
+    did_check_timestamps = FALSE;
+}
+
+#if defined(SIGCONT)
+static RETSIGTYPE sigcont_handler SIGPROTOARG;
+static int in_mch_suspend = FALSE;
+
+# if defined(_REENTRANT) && defined(SIGCONT)
 /*
  * On Solaris with multi-threading, suspending might not work immediately.
  * Catch the SIGCONT signal, which will be used as an indication whether the
@@ -1239,15 +1255,46 @@ deathtrap SIGDEFARG(sigarg)
  * volatile because it is used in signal handler sigcont_handler().
  */
 static volatile int sigcont_received;
-static RETSIGTYPE sigcont_handler SIGPROTOARG;
+# endif
 
 /*
  * signal handler for SIGCONT
  */
     static RETSIGTYPE
 sigcont_handler SIGDEFARG(sigarg)
 {
-    sigcont_received = TRUE;
+    if (in_mch_suspend)
+    {
+# if defined(_REENTRANT) && defined(SIGCONT)
+	sigcont_received = TRUE;
+# endif
+    }
+    else
+    {
+	// We didn't suspend ourselves, assume we were stopped by a SIGSTOP
+	// signal (which can't be intercepted) and get a SIGCONT.  Need to get
+	// back to a sane mode and redraw.
+	after_sigcont();
+
+	update_screen(CLEAR);
+	if (State & CMDLINE)
+	    redrawcmdline();
+	else if (State == HITRETURN || State == SETWSIZE || State == ASKMORE
+		|| State == EXTERNCMD || State == CONFIRM || exmode_active)
+	    repeat_message();
+	else if (redrawing())
+	    setcursor();
+#if defined(FEAT_INS_EXPAND)
+	if (pum_visible())
+	{
+	    redraw_later(NOT_VALID);
+	    ins_compl_show_pum();
+	}
+#endif
+	cursor_on_force();
+	out_flush();
+    }
+
     SIGRETURN;
 }
 #endif
@@ -1330,6 +1377,8 @@ mch_suspend(void)
 {
     /* BeOS does have SIGTSTP, but it doesn't work. */
 #if defined(SIGTSTP) && !defined(__BEOS__)
+    in_mch_suspend = TRUE;
+
     out_flush();	    /* needed to make cursor visible on some systems */
     settmode(TMODE_COOK);
     out_flush();	    /* needed to disable mouse on some systems */
@@ -1361,16 +1410,9 @@ mch_suspend(void)
 	    mch_delay(wait_time, FALSE);
     }
 # endif
+    in_mch_suspend = FALSE;
 
-# ifdef FEAT_TITLE
-    /*
-     * Set oldtitle to NULL, so the current title is obtained again.
-     */
-    VIM_CLEAR(oldtitle);
-# endif
-    settmode(TMODE_RAW);
-    need_check_timestamps = TRUE;
-    did_check_timestamps = FALSE;
+    after_sigcont();
 #else
     suspend_shell();
 #endif
@@ -1410,7 +1452,7 @@ set_signals(void)
 #ifdef SIGTSTP
     signal(SIGTSTP, restricted ? SIG_IGN : SIG_DFL);
 #endif
-#if defined(_REENTRANT) && defined(SIGCONT)
+#if defined(SIGCONT)
     signal(SIGCONT, sigcont_handler);
 #endif
 

src/proto/term.pro

@@ -50,6 +50,7 @@ void setmouse(void);
 int mouse_has(int c);
 int mouse_model_popup(void);
 void scroll_start(void);
+void cursor_on_force(void);
 void cursor_on(void);
 void cursor_off(void);
 void term_cursor_mode(int forced);

src/term.c

@@ -3788,17 +3788,24 @@ scroll_start(void)
 
 static int cursor_is_off = FALSE;
 
+/*
+ * Enable the cursor without checking if it's already enabled.
+ */
+    void
+cursor_on_force(void)
+{
+    out_str(T_VE);
+    cursor_is_off = FALSE;
+}
+
 /*
  * Enable the cursor.
  */
     void
 cursor_on(void)
 {
     if (cursor_is_off)
-    {
-	out_str(T_VE);
-	cursor_is_off = FALSE;
-    }
+	cursor_on_force();
 }
 
 /*

src/version.c

@@ -794,6 +794,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    244,
 /**/
     243,
 /**/