"GMT+1" is parsed as "GMT-1"

[Lyse]

When parsing timezones such as "GMT+1" (GMT plus one) the result is "GMT-1" (GMT minus one) and vice verca. Replacing "GMT" string with "UTC" shows same behaviour. However just "+1" or "-1" as timezone information works as expected.

Both dateutil versions 1.5 and 2.0 are affected by this issue.

>>> import dateutil.parser
>>> dateutil.parser.parse("25. Sep. 2012 15:00:00 GMT+1")
datetime.datetime(2012, 9, 25, 15, 0, tzinfo=tzoffset(None, -3600))
# Parsed timezone offset should be +3600.

>>> dateutil.parser.parse("25. Sep. 2012 15:00:00 GMT-1")
datetime.datetime(2012, 9, 25, 15, 0, tzinfo=tzoffset(None, 3600))
# Parsed timezone offset should be -3600.

>>> dateutil.parser.parse("25. Sep. 2012 15:00:00 +1")
datetime.datetime(2012, 9, 25, 15, 0, tzinfo=tzoffset(None, 3600))
# Parsed timezone offset is correct.

[Lennart Regebro (regebro-gmail)]

Parsing GTM+1 this way is actually a part of the Posix specification. This is therefore a feature, and not a bug.