Olson database name ambiguity

[Tom Yandell]

Hi

Apologies for cross posting this. I think that this is a problem in the
data in the Olson database, but as it is a binary format it is difficult
to verify this. I have come across this problem using the DateTime perl
module (version 0.28) whose data is generated from the Olson database.

The problem that I am experiencing is that the short name for timezones
for 'Europe/London' up until 1996 were either 'GMT' or 'BST' (depending
if daylight saving changes were in effect). From 1996 the name for the
timezone is the rather less precise 'GMT/BST' regardless of whether
daylight saving changes are in effect or not. I have attached a script
that demonstrates this, and its output.

Regards,
Tom

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winter 1970: BST (3600) ... summer 1970: BST (3600)
winter 1971: BST (3600) ... summer 1971: BST (3600)
winter 1972: GMT (0) ... summer 1972: BST (3600)
winter 1973: GMT (0) ... summer 1973: BST (3600)
winter 1974: GMT (0) ... summer 1974: BST (3600)
winter 1975: GMT (0) ... summer 1975: BST (3600)
winter 1976: GMT (0) ... summer 1976: BST (3600)
winter 1977: GMT (0) ... summer 1977: BST (3600)
winter 1978: GMT (0) ... summer 1978: BST (3600)
winter 1979: GMT (0) ... summer 1979: BST (3600)
winter 1980: GMT (0) ... summer 1980: BST (3600)
winter 1981: GMT (0) ... summer 1981: BST (3600)
winter 1982: GMT (0) ... summer 1982: BST (3600)
winter 1983: GMT (0) ... summer 1983: BST (3600)
winter 1984: GMT (0) ... summer 1984: BST (3600)
winter 1985: GMT (0) ... summer 1985: BST (3600)
winter 1986: GMT (0) ... summer 1986: BST (3600)
winter 1987: GMT (0) ... summer 1987: BST (3600)
winter 1988: GMT (0) ... summer 1988: BST (3600)
winter 1989: GMT (0) ... summer 1989: BST (3600)
winter 1990: GMT (0) ... summer 1990: BST (3600)
winter 1991: GMT (0) ... summer 1991: BST (3600)
winter 1992: GMT (0) ... summer 1992: BST (3600)
winter 1993: GMT (0) ... summer 1993: BST (3600)
winter 1994: GMT (0) ... summer 1994: BST (3600)
winter 1995: GMT (0) ... summer 1995: BST (3600)
winter 1996: GMT/BST (0) ... summer 1996: GMT/BST (3600)
winter 1997: GMT/BST (0) ... summer 1997: GMT/BST (3600)
winter 1998: GMT/BST (0) ... summer 1998: GMT/BST (3600)
winter 1999: GMT/BST (0) ... summer 1999: GMT/BST (3600)
winter 2000: GMT/BST (0) ... summer 2000: GMT/BST (3600)
winter 2001: GMT/BST (0) ... summer 2001: GMT/BST (3600)
winter 2002: GMT/BST (0) ... summer 2002: GMT/BST (3600)
winter 2003: GMT/BST (0) ... summer 2003: GMT/BST (3600)
winter 2004: GMT/BST (0) ... summer 2004: GMT/BST (3600)
winter 2005: GMT/BST (0) ... summer 2005: GMT/BST (3600)
winter 2006: GMT/BST (0) ... summer 2006: GMT/BST (3600)
winter 2007: GMT/BST (0) ... summer 2007: GMT/BST (3600)
winter 2008: GMT/BST (0) ... summer 2008: GMT/BST (3600)
winter 2009: GMT/BST (0) ... summer 2009: GMT/BST (3600)
winter 2010: GMT/BST (0) ... summer 2010: GMT/BST (3600)
winter 2011: GMT/BST (0) ... summer 2011: GMT/BST (3600)
winter 2012: GMT/BST (0) ... summer 2012: GMT/BST (3600)
winter 2013: GMT/BST (0) ... summer 2013: GMT/BST (3600)
winter 2014: GMT/BST (0) ... summer 2014: GMT/BST (3600)
winter 2015: GMT/BST (0) ... summer 2015: GMT/BST (3600)
winter 2016: GMT/BST (0) ... summer 2016: GMT/BST (3600)
winter 2017: GMT/BST (0) ... summer 2017: GMT/BST (3600)
winter 2018: GMT/BST (0) ... summer 2018: GMT/BST (3600)
winter 2019: GMT/BST (0) ... summer 2019: GMT/BST (3600)
winter 2020: GMT/BST (0) ... summer 2020: GMT/BST (3600)
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