patch 8.2.3484: crash when going through spell suggestions

Problem:    Crash when going through spell suggestions.
Solution:   Limit the text length for finding suggestions to the original
            length.  Do not update buffers when exiting. (closes #8965)

src/clipboard.c

@@ -199,7 +199,8 @@ clip_lose_selection(Clipboard_T *cbd)
 					    || get_real_state() == SELECTMODE)
 		&& (cbd == &clip_star ?
 				clip_isautosel_star() : clip_isautosel_plus())
-		&& HL_ATTR(HLF_V) != HL_ATTR(HLF_VNC))
+		&& HL_ATTR(HLF_V) != HL_ATTR(HLF_VNC)
+		&& !exiting)
 	{
 	    update_curbuf(INVERTED_ALL);
 	    setcursor();

src/spellsuggest.c

@@ -1178,6 +1178,11 @@ suggest_try_change(suginfo_T *su)
     p = su->su_badptr + su->su_badlen;
     (void)spell_casefold(curwin, p, (int)STRLEN(p), fword + n, MAXWLEN - n);
 
+    // Make sure the resulting text is not longer than the original text.
+    n = (int)STRLEN(su->su_badptr);
+    if (n < MAXWLEN)
+	fword[n] = NUL;
+
     for (lpi = 0; lpi < curwin->w_s->b_langp.ga_len; ++lpi)
     {
 	lp = LANGP_ENTRY(curwin->w_s->b_langp, lpi);

src/testdir/test_spell_utf8.vim

@@ -765,4 +765,20 @@ func Test_spellfile_value()
   set spellfile=Xdir/Xtest.utf-8.add,Xtest_other.add
 endfunc
 
+func Test_no_crash_with_weird_text()
+  new
+  let lines =<< trim END
+      r<sfile>
+      €
+
+
+      €
+  END
+  call setline(1, lines)
+  exe "%norm \<C-v>ez=>\<C-v>wzG"
+
+  bwipe!
+endfunc
+
+
 " vim: shiftwidth=2 sts=2 expandtab

src/version.c

@@ -757,6 +757,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    3484,
 /**/
     3483,
 /**/