From bd238bfd7c443fd974f5b7edd6c1abc0349bfa78 Mon Sep 17 00:00:00 2001
From: Lars Henriksen <LarsHenriksen@get2net.dk>
Date: Thu, 7 May 2020 21:39:23 +0200
Subject: Fix recurrence rule expansion with ordered weekday

When the order of a weekday in BYDAY rule expansion (like -5SA or 5SU
for monthly or 55WE for yearly) exceeds the number of available weekdays
in the period (month or year), rule expansion with negative order could
result in a floating point exception. The reason: the modified frequency
might become zero.

Solution. Check order against number of available weekdays and terminate
expansion early whenever possible (also for positive orders).

Signed-off-by: Lars Henriksen <LarsHenriksen@get2net.dk>
Signed-off-by: Lukas Fleischer <lfleischer@calcurse.org>
---
 test/recur-009.sh | 13 +++++++++++++
 1 file changed, 13 insertions(+)

(limited to 'test/recur-009.sh')

diff --git a/test/recur-009.sh b/test/recur-009.sh
index 6ee302d..2558b4c 100755
--- a/test/recur-009.sh
+++ b/test/recur-009.sh
@@ -6,6 +6,13 @@
 if [ "$1" = 'actual' ]; then
   "$CALCURSE" --read-only -D "$DATA_DIR"/ -c "$DATA_DIR/rfc5545" \
   -Q --from 1/1/1996 --to 12/31/2007 --filter-type recur
+  echo ""
+  echo "Floating point exception?"
+  "$CALCURSE" --read-only -D "$DATA_DIR"/ -c "$DATA_DIR/rfc5545" \
+  -Q --day 8/1/2020 --filter-type recur &&
+  "$CALCURSE" --read-only -D "$DATA_DIR"/ -c "$DATA_DIR/rfc5545" \
+  -Q --day 11/1/2020 --filter-type recur &&
+  echo "No Floating point exception on November 1, 2020"
 elif [ "$1" = 'expected' ]; then
   cat <<EOD
 11/05/96:
@@ -5323,6 +5330,12 @@ elif [ "$1" = 'expected' ]; then
 
 12/31/07:
  * Every Sunday and Monday, every other year (FREQ=YEARLY;INTERVAL=2;BYDAY=SU,MO)
+
+Floating point exception?
+08/01/20:
+ - 08:41 -> 10:11
+	negative ordered weekday may not exist
+No Floating point exception on November 1, 2020
 EOD
 else
   ./run-test "$0"
-- 
cgit v1.2.3-54-g00ecf