ChangeLog for Chrono
====================

This documents all notable changes to [Chrono](https://github.com/chronotope/chrono).

Chrono obeys the principle of [Semantic Versioning](http://semver.org/).

There were/are numerous minor versions before 1.0 due to the language changes.
Versions with only mechnical changes will be omitted from the following list.

## 0.3.0 (2017-02-07)

The project has moved to the [Chronotope](https://github.com/chronotope/) organization.

### Added

- `chrono::prelude` module has been added. All other glob imports are now discouraged.

- `FixedOffset` can be added to or subtracted from any timelike types.

    - `FixedOffset::local_minus_utc` and `FixedOffset::utc_minus_local` methods have been added.
      Note that the old `Offset::local_minus_utc` method is gone; see below.

- Serde support for non-self-describing formats like Bincode is added. (#89)

- Added `Item::Owned{Literal,Space}` variants for owned formatting items. (#76)

- Formatting items and the `Parsed` type have been slightly adjusted so that
  they can be internally extended without breaking any compatibility.

- `Weekday` is now `Hash`able. (#109)

- `ParseError` now implements `Eq` as well as `PartialEq`. (#114)

- More documentation improvements. (#101, #108, #112)

### Changed

- Chrono now only supports Rust 1.13.0 or later (previously: Rust 1.8.0 or later).

- Serde 0.9 is now supported.
  Due to the API difference, support for 0.8 or older is discontinued. (#122)

- Rustc-serialize implementations are now on par with corresponding Serde implementations.
  They both standardize on the `std::fmt::Debug` textual output.

  **This is a silent breaking change (hopefully the last though).**
  You should be prepared for the format change if you depended on rustc-serialize.

- `Offset::local_minus_utc` is now `Offset::fix`, and returns `FixedOffset` instead of a duration.

  This makes every time zone operation operate within a bias less than one day,
  and vastly simplifies many logics.

- `chrono::format::format` now receives `FixedOffset` instead of `time::Duration`.

- The following methods and implementations have been renamed and older names have been *removed*.
  The older names will be reused for the same methods with `std::time::Duration` in the future.

    - `checked_*` → `checked_*_signed` in `Date`, `DateTime`, `NaiveDate` and `NaiveDateTime` types

    - `overflowing_*` → `overflowing_*_signed` in the `NaiveTime` type

    - All subtraction implementations between two time instants have been moved to
      `signed_duration_since`, following the naming in `std::time`.

### Fixed

- Fixed a panic when the `Local` offset receives a leap second. (#123)

### Removed

- Rustc-serialize support for `Date<Tz>` types and all offset types has been dropped.

  These implementations were automatically derived and never had been in a good shape.
  Moreover there are no corresponding Serde implementations, limiting their usefulness.
  In the future they may be revived with more complete implementations.

- The following method aliases deprecated in the 0.2 branch have been removed.

    - `DateTime::num_seconds_from_unix_epoch` (→ `DateTime::timestamp`)
    - `NaiveDateTime::from_num_seconds_from_unix_epoch` (→ `NaiveDateTime::from_timestamp`)
    - `NaiveDateTime::from_num_seconds_from_unix_epoch_opt` (→ `NaiveDateTime::from_timestamp_opt`)
    - `NaiveDateTime::num_seconds_unix_epoch` (→ `NaiveDateTime::timestamp`)

- Formatting items are no longer `Copy`, except for `chrono::format::Pad`.

- `chrono::offset::add_with_leapsecond` has been removed.
  Use a direct addition with `FixedOffset` instead.

## 0.2.25 (2016-08-04)

This is the last version officially supports Rust 1.12.0 or older.

(0.2.24 was accidentally uploaded without a proper check for warnings in the default state,
and replaced by 0.2.25 very shortly. Duh.)

### Added

- Serde 0.8 is now supported. 0.7 also remains supported. (#86)

### Fixed

- The deserialization implementation for rustc-serialize now properly verifies the input.
  All serialization codes are also now thoroughly tested. (#42)

## 0.2.23 (2016-08-03)

### Added

- The documentation was greatly improved for several types,
  and tons of cross-references have been added. (#77, #78, #80, #82)

- `DateTime::timestamp_subsec_{millis,micros,nanos}` methods have been added. (#81)

### Fixed

- When the system time records a leap second,
  the nanosecond component was mistakenly reset to zero. (#84)

- `Local` offset misbehaves in Windows for August and later,
  due to the long-standing libtime bug (dates back to mid-2015).
  Workaround has been implemented. (#85)

## 0.2.22 (2016-04-22)

### Fixed

- `%.6f` and `%.9f` used to print only three digits when the nanosecond part is zero. (#71)
- The documentation for `%+` has been updated to reflect the current status. (#71)

## 0.2.21 (2016-03-29)

### Fixed

- `Fixed::LongWeekdayName` was unable to recognize `"sunday"` (whoops). (#66)

## 0.2.20 (2016-03-06)

### Changed

- `serde` dependency has been updated to 0.7. (#63, #64)

## 0.2.19 (2016-02-05)

### Added

- The documentation for `Date` is made clear about its ambiguity and guarantees.

### Fixed

- `DateTime::date` had been wrong when the local date and the UTC date is in disagreement. (#61)

## 0.2.18 (2016-01-23)

### Fixed

- Chrono no longer pulls a superfluous `rand` dependency. (#57)

## 0.2.17 (2015-11-22)

### Added

- Naive date and time types and `DateTime` now have a `serde` support.
  They serialize as an ISO 8601 / RFC 3339 string just like `Debug`. (#51)

## 0.2.16 (2015-09-06)

### Added

- Added `%.3f`, `%.6f` and `%.9f` specifier for formatting fractional seconds
  up to 3, 6 or 9 decimal digits. This is a natural extension to the existing `%f`.
  Note that this is (not yet) generic, no other value of precision is supported. (#45)

### Changed

- Forbade unsized types from implementing `Datelike` and `Timelike`.
  This does not make a big harm as any type implementing them should be already sized
  to be practical, but this change still can break highly generic codes. (#46)

### Fixed

- Fixed a broken link in the `README.md`. (#41)

## 0.2.15 (2015-07-05)

### Added

- Padding modifiers `%_?`, `%-?` and `%0?` are implemented.
  They are glibc extensions which seem to be reasonably widespread (e.g. Ruby).

- Added `%:z` specifier and corresponding formatting items
  which is essentially same to `%z` but with a colon.

- Added a new specifier `%.f` which precision adapts from the input.
  This was added as a response to the UX problems in the original nanosecond specifier `%f`.

### Fixed

- `Numeric::Timestamp` specifier (`%s`) was ignoring the time zone offset when provided.

- Improved the documentation and associated tests for `strftime`.

## 0.2.14 (2015-05-15)

### Fixed

- `NaiveDateTime +/- Duration` or `NaiveTime +/- Duration` could have gone wrong
  when the `Duration` to be added is negative and has a fractional second part.
  This was caused by an underflow in the conversion from `Duration` to the parts;
  the lack of tests for this case allowed a bug. (#37)

## 0.2.13 (2015-04-29)

### Added

- The optional dependency on `rustc_serialize` and
  relevant `Rustc{En,De}codable` implementations for supported types has been added.
  This is enabled by the `rustc-serialize` Cargo feature. (#34)

### Changed

- `chrono::Duration` reexport is changed to that of crates.io `time` crate.
  This enables Rust 1.0 beta compatibility.

## 0.2.4 (2015-03-03)

### Fixed

- Clarified the meaning of `Date<Tz>` and fixed unwanted conversion problem
  that only occurs with positive UTC offsets. (#27)

## 0.2.3 (2015-02-27)

### Added

- `DateTime<Tz>` and `Date<Tz>` is now `Copy`/`Send` when `Tz::Offset` is `Copy`/`Send`.
  The implementations for them were mistakenly omitted. (#25)

### Fixed

- `Local::from_utc_datetime` didn't set a correct offset. (#26)

## 0.2.1 (2015-02-21)

### Changed

- `DelayedFormat` no longer conveys a redundant lifetime.

## 0.2.0 (2015-02-19)

### Added

- `Offset` is splitted into `TimeZone` (constructor) and `Offset` (storage) types.
  You would normally see only the former, as the latter is mostly an implementation detail.
  Most importantly, `Local` now can be used to directly construct timezone-aware values.

  Some types (currently, `UTC` and `FixedOffset`) are both `TimeZone` and `Offset`,
  but others aren't (e.g. `Local` is not what is being stored to each `DateTime` values).

- `LocalResult::map` convenience method has been added.

- `TimeZone` now allows a construction of `DateTime` values from UNIX timestamp,
  via `timestamp` and `timestamp_opt` methods.

- `TimeZone` now also has a method for parsing `DateTime`, namely `datetime_from_str`.

- The following methods have been added to all date and time types:

    - `checked_add`
    - `checked_sub`
    - `format_with_items`

- The following methods have been added to all timezone-aware types:

    - `timezone`
    - `with_timezone`
    - `naive_utc`
    - `naive_local`

- `parse_from_str` method has been added to all naive types and `DateTime<FixedOffset>`.

- All naive types and instances of `DateTime` with time zones `UTC`, `Local` and `FixedOffset`
  implement the `FromStr` trait. They parse what `std::fmt::Debug` would print.

- `chrono::format` has been greatly rewritten.

    - The formatting syntax parser is modular now, available at `chrono::format::strftime`.

    - The parser and resolution algorithm is also modular, the former is available at
      `chrono::format::parse` while the latter is available at `chrono::format::parsed`.

    - Explicit support for RFC 2822 and 3339 syntaxes is landed.

    - There is a minor formatting difference with atypical values,
      e.g. for years not between 1 BCE and 9999 CE.

### Changed

- Most uses of `Offset` are converted to `TimeZone`.
  In fact, *all* user-facing code is expected to be `Offset`-free.

- `[Naive]DateTime::*num_seconds_from_unix_epoch*` methods have been renamed to
  simply `timestamp` or `from_timestamp*`. The original names have been deprecated.

### Removed

- `Time` has been removed. This also prompts a related set of methods in `TimeZone`.

  This is in principle possible, but in practice has seen a little use
  because it can only be meaningfully constructed via an existing `DateTime` value.
  This made many operations to `Time` unintuitive or ambiguous,
  so we simply let it go.

  In the case that `Time` is really required, one can use a simpler `NaiveTime`.
  `NaiveTime` and `NaiveDate` can be freely combined and splitted,
  and `TimeZone::from_{local,utc}_datetime` can be used to convert from/to the local time.

- `with_offset` method has been removed. Use `with_timezone` method instead.
  (This is not deprecated since it is an integral part of offset reform.)

## 0.1.14 (2015-01-10)

### Added

- Added a missing `std::fmt::String` impl for `Local`.

## 0.1.13 (2015-01-10)

### Changed

- Most types now implement both `std::fmt::Show` and `std::fmt::String`,
  with the former used for the stricter output and the latter used for more casual output.

### Removed

- `Offset::name` has been replaced by a `std::fmt::String` implementation to `Offset`.

## 0.1.12 (2015-01-08)

### Removed

- `Duration + T` no longer works due to the updated impl reachability rules.
  Use `T + Duration` as a workaround.

## 0.1.4 (2014-12-13)

### Fixed

- Fixed a bug that `Date::and_*` methods with an offset that can change the date are
  off by one day.

## 0.1.3 (2014-11-28)

### Added

- `{Date,Time,DateTime}::with_offset` methods have been added.

- `LocalResult` now implements a common set of traits.

- `LocalResult::and_*` methods have been added.
  They are useful for safely chaining `LocalResult<Date<Off>>` methods
  to make `LocalResult<DateTime<Off>>`.

### Changed

- `Offset::name` now returns `SendStr`.

- `{Date,Time} - Duration` overloadings are now allowed.

## 0.1.2 (2014-11-24)

### Added

- `Duration + Date` overloading is now allowed.

### Changed

- Chrono no longer needs `num` dependency.

## 0.1.0 (2014-11-20)

The initial version that was available to `crates.io`.