patch 8.2.4327: may end up with no current buffer

Problem:    May end up with no current buffer.
Solution:   When deleting the current buffer to not pick a quickfix buffer as
            the new current buffer.

src/buffer.c

@@ -1430,8 +1430,14 @@ do_buffer_ext(
 		buf = buflist_findnr(curwin->w_jumplist[jumpidx].fmark.fnum);
 		if (buf != NULL)
 		{
-		    if (buf == curbuf || !buf->b_p_bl)
+		    // Skip current and unlisted bufs.  Also skip a quickfix
-			buf = NULL;	// skip current and unlisted bufs
+		    // buffer, it might be deleted soon.
+		    if (buf == curbuf || !buf->b_p_bl
+#if defined(FEAT_QUICKFIX)
+			    || bt_quickfix(buf)
+#endif
+			    )
+			buf = NULL;
 		    else if (buf->b_ml.ml_mfp == NULL)
 		    {
 			// skip unloaded buf, but may keep it for later
@@ -1467,7 +1473,11 @@ do_buffer_ext(
 		    continue;
 		}
 		// in non-help buffer, try to skip help buffers, and vv
-		if (buf->b_help == curbuf->b_help && buf->b_p_bl)
+		if (buf->b_help == curbuf->b_help && buf->b_p_bl
+#if defined(FEAT_QUICKFIX)
+			    && !bt_quickfix(buf)
+#endif
+			   )
 		{
 		    if (buf->b_ml.ml_mfp != NULL)   // found loaded buffer
 			break;
@@ -1485,7 +1495,11 @@ do_buffer_ext(
 	if (buf == NULL)	// No loaded buffer, find listed one
 	{
 	    FOR_ALL_BUFFERS(buf)
-		if (buf->b_p_bl && buf != curbuf)
+		if (buf->b_p_bl && buf != curbuf
+#if defined(FEAT_QUICKFIX)
+			    && !bt_quickfix(buf)
+#endif
+		       )
 		    break;
 	}
 	if (buf == NULL)	// Still no buffer, just take one
@@ -1494,6 +1508,10 @@ do_buffer_ext(
 		buf = curbuf->b_next;
 	    else
 		buf = curbuf->b_prev;
+#if defined(FEAT_QUICKFIX)
+	    if (bt_quickfix(buf))
+		buf = NULL;
+#endif
 	}
     }
 

src/testdir/test_quickfix.vim

@@ -5851,5 +5851,30 @@ func Test_lopen_bwipe()
   delfunc R
 endfunc
 
+" Another sequence of commands that caused all buffers to be wiped out
+func Test_lopen_bwipe_all()
+  let lines =<< trim END
+    func R()
+      silent! tab lopen
+      e foo
+      silent! lfile
+    endfunc
+    cal R()
+    exe "norm \<C-W>\<C-V>0"
+    cal R()
+    bwipe
+
+    call writefile(['done'], 'Xresult')
+    qall!
+  END
+  call writefile(lines, 'Xscript')
+  if RunVim([], [], '-u NONE -n -X -Z -e -m -s -S Xscript')
+    call assert_equal(['done'], readfile('Xresult'))
+  endif
+
+  call delete('Xscript')
+  call delete('Xresult')
+endfunc
+
 
 " vim: shiftwidth=2 sts=2 expandtab

src/version.c

@@ -746,6 +746,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    4327,
 /**/
     4326,
 /**/