patch 8.0.0542: getpos() can return a negative line numberv8.0.0542

Problem:    getpos() can return a negative line number. (haya14busa)
Solution:   Handle a zero topline and botline. (closes #1613)

1 files changed, 5 insertions, 2 deletions

diff --git a/src/eval.c b/src/eval.c
index e588c23e9..261ece85c 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -6120,13 +6120,16 @@ var2fpos(
 	if (name[1] == '0')		/* "w0": first visible line */
 	{
 	    update_topline();
-	    pos.lnum = curwin->w_topline;
+	    /* In silent Ex mode topline is zero, but that's not a valid line
+	     * number; use one instead. */
+	    pos.lnum = curwin->w_topline > 0 ? curwin->w_topline : 1;
 	    return &pos;
 	}
 	else if (name[1] == '$')	/* "w$": last visible line */
 	{
 	    validate_botline();
-	    pos.lnum = curwin->w_botline - 1;
+	    /* In silent Ex mode botline is zero, return zero then. */
+	    pos.lnum = curwin->w_botline > 0 ? curwin->w_botline - 1 : 0;
 	    return &pos;
 	}
     }