[tz] [PROPOSED PATCH] Move one out-of-scope zone to 'backzone'

Paul Eggert eggert at cs.ucla.edu
Tue Mar 24 19:37:51 UTC 2015


* NEWS: Document this.
* backzone (Mont, America/Montreal):
Move this out-of-scope data here from 'northamerica'.
* checktab.awk: Remove special case for America/Montreal,
that was added to this file "temporarily" on 2013-09-11.
* northamerica (America/Montreal): Now a link to America/Toronto.
---
 NEWS         | 11 +++++++++++
 backzone     | 40 ++++++++++++++++++++++++++++++++++++++++
 checktab.awk |  3 ---
 northamerica | 41 ++++-------------------------------------
 4 files changed, 55 insertions(+), 40 deletions(-)

diff --git a/NEWS b/NEWS
index ce6ac40..ddfd702 100644
--- a/NEWS
+++ b/NEWS
@@ -1,5 +1,16 @@
 News for the tz database
 
+Unreleased, experimental changes
+
+  Changes affecting past time stamps
+
+    One more zone has been turned into a link, as it differed
+    from an existing zone only for older time stamps.  As usual,
+    this change affects UTC offsets in pre-1970 time stamps only.
+    The zone's old contents have been moved to the 'backzone' file.
+    The affected zone is America/Montreal.
+
+
 Release 2015b - 2015-03-19 23:28:11 -0700
 
   Changes affecting future time stamps
diff --git a/backzone b/backzone
index 31a3f5a..6b392bd 100644
--- a/backzone
+++ b/backzone
@@ -311,6 +311,46 @@ Zone	America/Grenada	-4:07:00 -	LMT	1911 Jul # St George's
 Zone America/Guadeloupe	-4:06:08 -	LMT	1911 Jun  8 # Pointe-à-Pitre
 			-4:00	 -	AST
 
+# Canada
+#
+# From Paul Eggert (2015-03-24):
+# Since 1970 most of Quebec has been like Toronto; see
+# America/Toronto.  However, earlier versions of the tz database
+# mistakenly relied on data from Shanks & Pottenger saying that Quebec
+# differed from Ontario after 1970, and the following rules and zone
+# were created for most of Quebec from the incorrect Shanks &
+# Pottenger data.  The post-1970 entries have been corrected, but the
+# pre-1970 entries are unchecked and probably have errors.
+#
+# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+Rule	Mont	1917	only	-	Mar	25	2:00	1:00	D
+Rule	Mont	1917	only	-	Apr	24	0:00	0	S
+Rule	Mont	1919	only	-	Mar	31	2:30	1:00	D
+Rule	Mont	1919	only	-	Oct	25	2:30	0	S
+Rule	Mont	1920	only	-	May	 2	2:30	1:00	D
+Rule	Mont	1920	1922	-	Oct	Sun>=1	2:30	0	S
+Rule	Mont	1921	only	-	May	 1	2:00	1:00	D
+Rule	Mont	1922	only	-	Apr	30	2:00	1:00	D
+Rule	Mont	1924	only	-	May	17	2:00	1:00	D
+Rule	Mont	1924	1926	-	Sep	lastSun	2:30	0	S
+Rule	Mont	1925	1926	-	May	Sun>=1	2:00	1:00	D
+Rule	Mont	1927	1937	-	Apr	lastSat	24:00	1:00	D
+Rule	Mont	1927	1937	-	Sep	lastSat	24:00	0	S
+Rule	Mont	1938	1940	-	Apr	lastSun	0:00	1:00	D
+Rule	Mont	1938	1939	-	Sep	lastSun	0:00	0	S
+Rule	Mont	1946	1973	-	Apr	lastSun	2:00	1:00	D
+Rule	Mont	1945	1948	-	Sep	lastSun	2:00	0	S
+Rule	Mont	1949	1950	-	Oct	lastSun	2:00	0	S
+Rule	Mont	1951	1956	-	Sep	lastSun	2:00	0	S
+Rule	Mont	1957	1973	-	Oct	lastSun	2:00	0	S
+Zone America/Montreal	-4:54:16 -	LMT	1884
+			-5:00	Mont	E%sT	1918
+			-5:00	Canada	E%sT	1919
+			-5:00	Mont	E%sT	1942 Feb  9  2:00s
+			-5:00	Canada	E%sT	1946
+			-5:00	Mont	E%sT	1974
+			-5:00	Canada	E%sT
+
 # Montserrat
 # From Paul Eggert (2006-03-22):
 # In 1995 volcanic eruptions forced evacuation of Plymouth, the capital.
diff --git a/checktab.awk b/checktab.awk
index cf2c726..de98299 100644
--- a/checktab.awk
+++ b/checktab.awk
@@ -9,9 +9,6 @@ BEGIN {
 	if (!zone_table) zone_table = "zone1970.tab"
 	if (!want_warnings) want_warnings = -1
 
-	# A special (and we hope temporary) case.
-	tztab["America/Montreal"] = 1
-
 	while (getline <iso_table) {
 		iso_NR++
 		if ($0 ~ /^#/) continue
diff --git a/northamerica b/northamerica
index 77463da..6b65d6d 100644
--- a/northamerica
+++ b/northamerica
@@ -1331,14 +1331,9 @@ Zone America/Moncton	-4:19:08 -	LMT	1883 Dec  9
 
 # Quebec
 
-# From Paul Eggert (2013-08-30):
-# Since 1970 most of Quebec has been like Toronto.
-# However, because earlier versions of the tz database mistakenly relied on data
-# from Shanks & Pottenger saying that Quebec differed from Ontario after 1970,
-# a separate entry was created for most of Quebec.  We're loath to lose
-# its pre-1970 info, even though the tz database is normally limited to
-# zones that differ after 1970, so keep this otherwise out-of-scope entry.
-
+# From Paul Eggert (2015-03-24):
+# See America/Toronto for most of Quebec, including Montreal.
+#
 # Matthews and Vincent (1998) also write that Quebec east of the -63
 # meridian is supposed to observe AST, but residents as far east as
 # Natashquan use EST/EDT, and residents east of Natashquan use AST.
@@ -1352,39 +1347,10 @@ Zone America/Moncton	-4:19:08 -	LMT	1883 Dec  9
 # For lack of better info, guess this practice began around 1970, contra to
 # Shanks & Pottenger who have this region observing AST/ADT.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
-Rule	Mont	1917	only	-	Mar	25	2:00	1:00	D
-Rule	Mont	1917	only	-	Apr	24	0:00	0	S
-Rule	Mont	1919	only	-	Mar	31	2:30	1:00	D
-Rule	Mont	1919	only	-	Oct	25	2:30	0	S
-Rule	Mont	1920	only	-	May	 2	2:30	1:00	D
-Rule	Mont	1920	1922	-	Oct	Sun>=1	2:30	0	S
-Rule	Mont	1921	only	-	May	 1	2:00	1:00	D
-Rule	Mont	1922	only	-	Apr	30	2:00	1:00	D
-Rule	Mont	1924	only	-	May	17	2:00	1:00	D
-Rule	Mont	1924	1926	-	Sep	lastSun	2:30	0	S
-Rule	Mont	1925	1926	-	May	Sun>=1	2:00	1:00	D
-Rule	Mont	1927	1937	-	Apr	lastSat	24:00	1:00	D
-Rule	Mont	1927	1937	-	Sep	lastSat	24:00	0	S
-Rule	Mont	1938	1940	-	Apr	lastSun	0:00	1:00	D
-Rule	Mont	1938	1939	-	Sep	lastSun	0:00	0	S
-Rule	Mont	1946	1973	-	Apr	lastSun	2:00	1:00	D
-Rule	Mont	1945	1948	-	Sep	lastSun	2:00	0	S
-Rule	Mont	1949	1950	-	Oct	lastSun	2:00	0	S
-Rule	Mont	1951	1956	-	Sep	lastSun	2:00	0	S
-Rule	Mont	1957	1973	-	Oct	lastSun	2:00	0	S
-
 # Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
 Zone America/Blanc-Sablon -3:48:28 -	LMT	1884
 			-4:00	Canada	A%sT	1970
 			-4:00	-	AST
-Zone America/Montreal	-4:54:16 -	LMT	1884
-			-5:00	Mont	E%sT	1918
-			-5:00	Canada	E%sT	1919
-			-5:00	Mont	E%sT	1942 Feb  9  2:00s
-			-5:00	Canada	E%sT	1946
-			-5:00	Mont	E%sT	1974
-			-5:00	Canada	E%sT
 
 # Ontario
 
@@ -1596,6 +1562,7 @@ Zone America/Toronto	-5:17:32 -	LMT	1895
 			-5:00	Canada	E%sT	1946
 			-5:00	Toronto	E%sT	1974
 			-5:00	Canada	E%sT
+Link America/Toronto America/Montreal
 Zone America/Thunder_Bay -5:57:00 -	LMT	1895
 			-6:00	-	CST	1910
 			-5:00	-	EST	1942
-- 
2.1.0




More information about the tz mailing list