Issue #14879 has been updated by ioquatix (Samuel Williams).


Jeremy, thanks for your interest.

Here is a minimal repro:

```
#!/usr/bin/env ruby

# https://bugs.ruby-lang.org/issues/14879
require 'time'

ENV['TZ'] = "Pacific/Auckland"
time = Time.parse("5pm")
ENV['TZ'] = "UTC"

puts time
puts time.utc_offset
puts (time + 1).utc_offset
puts time + 1
```

Thanks for the suggestion regarding `ZoneOffset`. However, that does not seem sufficient for capturing DST rules?

----------------------------------------
Bug #14879: Adding/subtracting from time can change utc_offset unexpectedly.
https://bugs.ruby-lang.org/issues/14879#change-72721

* Author: ioquatix (Samuel Williams)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
* ruby -v: 
* Backport: 2.3: UNKNOWN, 2.4: UNKNOWN, 2.5: UNKNOWN
----------------------------------------
I have been having some problems with `Time`. When I add or subtract seconds, sometimes the utc_offset is changed unexpectedly.

```
$ ruby -e 'require "time"; puts Time.parse("5pm NZT")'            
2018-06-29 17:00:00 +1200

$ ruby -e 'require "time"; puts Time.parse("5pm NZT") + 1'
2018-06-29 17:00:01 +1200

$ TZ=UTC ruby -e 'require "time"; puts Time.parse("5pm NZT") + 1'
2018-06-29 17:00:01 +0000
```

This seems like strange behaviour. The `utc_offset` shouldn't change IMHO.



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