Work to add UTC tracking to wall-times

[clsql.git] / ChangeLog

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+2018-02-03 Russ Tyndall <russ@acceleration.net>
+       * sql/time.lisp, tests/time.lisp:       
+       Better distinguishing between zoneless timestamps and UTC times,
+       particularly as relates to postgresql-socket(3) backends. Without
+       this change, timestamptzs are read as localtimes and saved as
+       localtimes, when they should be read and printed as UTC times,
+       this bug will lead to dates changing every save as they are being
+       reconverted to UTC again.
+
+       We followed a minimal approach (following postgresql' lead), we
+       simply add a is-utc? boolean.  Before this, zoned times were
+       converted to UTC, but since we never tracked that it was a UTC
+       time vs a zoneless time, there was conflation between the two.  In
+       order to preserver comparability between dates and times that are
+       local vs UTC. I wrote a `time-to-utc` utilizing decode-time's
+       implementation dependent timezone defaulting.
+       (I verified the math by comparing results to the local-time
+       library from quicklisp).
+
+       Ultimately, adoption of a third party datetime library is my
+       strong preference (eg: local-time).  While this project has, as a
+       whole refrained from outside requirements, I think that we should
+       consider moving to local-time as our date / time format, or
+       providing that as an option, both to support a semi standardized
+       eco system, and also to have a more robust timestamp implementation.
+
+
 2016-01-26 Kevin Rosenberg <kevin@rosenberg.net>
        * Version 6.7.0 release
        * sql/utils.lisp: Apply patch from Martin Simmons for