From 15e0ac32c17bdb9c7d480a65fbda77e6c5e7d808 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Wed, 23 Dec 2020 11:11:31 -0800
Subject: [PATCH] Fix rearguard.zi corruption in 2020e

Problem reported by Deborah Goldsmith in:
https://mm.icann.org/pipermail/tz/2020-December/029637.html
* Makefile (check_public): Also check vanguard.zi, main.zi,
rearguard.zi, to prevent similar problems from recurring.
* NEWS: Mention this.
* ziguard.awk: Be pickier about adjusting comments in
the Europe/Prague and Africa/Windhoek, partly by adding
a check already present for Europe/Dublin.
---
 Makefile    | 5 ++++-
 NEWS        | 8 ++++++++
 ziguard.awk | 9 +++++----
 3 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/Makefile b/Makefile
index 5064a19..1136af9 100644
--- a/Makefile
+++ b/Makefile
@@ -945,7 +945,10 @@ check_public: $(VERSION_DEPS)
 		mkdir public.dir
 		ln $(VERSION_DEPS) public.dir
 		cd public.dir && $(MAKE) CFLAGS='$(GCC_DEBUG_FLAGS)' ALL
-		for i in $(TDATA_TO_CHECK) public.dir/tzdata.zi; do \
+		for i in $(TDATA_TO_CHECK) public.dir/tzdata.zi \
+		    public.dir/vanguard.zi public.dir/main.zi \
+		    public.dir/rearguard.zi; \
+		do \
 		  public.dir/zic -v -d public.dir/zoneinfo $$i 2>&1 || exit; \
 		done
 		public.dir/zic -v -d public.dir/zoneinfo-all $(TDATA_TO_CHECK)
diff --git a/NEWS b/NEWS
index 6014b45..a0863fb 100644
--- a/NEWS
+++ b/NEWS
@@ -1,5 +1,13 @@
 News for the tz database
 
+Unreleased, experimental changes
+
+  Change to build procedure
+
+    'make rearguard_tarballs' no longer generates a bad rearguard.zi,
+    fixing a 2020e bug.  (Problem reported by Deborah Goldsmith.)
+
+
 Release 2020e - 2020-12-22 15:14:34 -0800
 
   Briefly:
diff --git a/ziguard.awk b/ziguard.awk
index e27e799..7d6f7c9 100644
--- a/ziguard.awk
+++ b/ziguard.awk
@@ -37,7 +37,7 @@ DATAFORM != "main" {
 
   # If this line should differ due to Czechoslovakia using negative SAVE values,
   # uncomment the desired version and comment out the undesired one.
-  if (zone == "Europe/Prague" && /1947 Feb 23/) {
+  if (zone == "Europe/Prague" && /^#?[\t ]+[01]:00[\t ]/ && /1947 Feb 23/) {
     if (($(in_comment + 2) != "-") == vanguard) {
       uncomment = in_comment
     } else {
@@ -65,10 +65,11 @@ DATAFORM != "main" {
   # uncomment the desired version and comment out the undesired one.
   Rule_Namibia = /^#?Rule[\t ]+Namibia[\t ]/
   Zone_using_Namibia_rule \
-    = (zone == "Africa/Windhoek" \
+    = (zone == "Africa/Windhoek" && /^#?[\t ]+[12]:00[\t ]/ \
        && ($(in_comment + 2) == "Namibia" \
-	   || (1994 <= $(in_comment + 4) && $(in_comment + 4) <= 2017) \
-	   || in_comment + 3 == NF))
+	   || ($(in_comment + 2) == "-" && $(in_comment + 3) == "CAT" \
+	       && ((1994 <= $(in_comment + 4) && $(in_comment + 4) <= 2017) \
+		   || in_comment + 3 == NF))))
   if (Rule_Namibia || Zone_using_Namibia_rule) {
       if ((Rule_Namibia \
 	   ? ($(in_comment + 9) ~ /^-/ \
-- 
1.8.3.1