Breaking changes:

• #1339: zapslog: Drop HandlerOptions in favor of HandlerOption, which uses the functional options pattern.
• #1339: zapslog: Rename AddSource option to WithCaller.

Enhancements:

• #1339: zapslog: Record stack traces for error logs or higher. The new AddStackAt option changes this level.

Bug fixes:

• #1344, #1408: zapslog: Comply fully with slog.Handler contract. This includes ignoring empty Attrs, inlining Groups with empty names, and omitting groups with no attributes.

Thanks to @zekth and @arukiidou for their contributions to this release.

Enhancements:

• #1378: Add WithLazy method for SugaredLogger.
• #1399: zaptest: Add NewTestingWriter for customizing TestingWriter with more flexibility than NewLogger.
• #1406: Add Log, Logw, Logln methods for SugaredLogger.
• #1416: Add WithPanicHook option for testing panic logs.

Thanks to @defval, @dimmo, @arxeiss, and @MKrupauskas for their contributions to this release.

Enhancements:

• #1297: Add Dict as a Field.
• #1319: Add WithLazy method to Logger which lazily evaluates the structured context.
• #1350: String encoding is much (~50%) faster now.

Thanks to @hhk7734, @jquirke, @cdvr1993 for their contributions to this release.

This release contains several improvements including performance, API additions, and two new experimental packages whose APIs are unstable and may change in the future.

Enhancements:

• #1246: Add zap/exp/zapslog package for integration with slog.
• #1273: Add Name to Logger which returns the Logger's name if one is set.
• #1281: Add zap/exp/expfield package which contains helper methods Str and Strs for constructing String-like zap.Fields.
• #1310: Reduce stack size on Any.

Thanks to @knight42, @dzakaammar, @bcspragu, and @rexywork for their contributions to this release.

Enhancements:

• #1148: Add Level to both Logger and SugaredLogger that reports the current minimum enabled log level.
• #1185: SugaredLogger turns errors to zap.Error automatically.

Thanks to @Abirdcfly, @craigpastro, @nnnkkk7, and @sashamelentyev for their contributions to this release.

Enhancements:

• #1147: Add a zapcore.LevelOf function to determine the level of a LevelEnabler or Core.
• #1155: Add zap.Stringers field constructor to log arrays of objects that implement String() string.

Enhancements:

• #1071: Add zap.Objects and zap.ObjectValues field constructors to log arrays of objects. With these two constructors, you don't need to implement zapcore.ArrayMarshaler for use with zap.Array if those objects implement zapcore.ObjectMarshaler.
• #1079: Add SugaredLogger.WithOptions to build a copy of an existing SugaredLogger with the provided options applied.
• #1080: Add *ln variants to SugaredLogger for each log level. These functions provide a string joining behavior similar to fmt.Println.
• #1088: Add zap.WithFatalHook option to control the behavior of the logger for Fatal-level log entries. This defaults to exiting the program.
• #1108: Add a zap.Must function that you can use with NewProduction or NewDevelopment to panic if the system was unable to build the logger.
• #1118: Add a Logger.Log method that allows specifying the log level for a statement dynamically.

Thanks to @cardil, @craigpastro, @sashamelentyev, @shota3506, and @zhupeijun for their contributions to this release.

1.21.0 (7 Feb 2022)

Enhancements:

• #1047: Add zapcore.ParseLevel to parse a Level from a string.
• #1048: Add zap.ParseAtomicLevel to parse an AtomicLevel from a string.

Bugfixes:

• #1058: Fix panic in JSON encoder when EncodeLevel is unset.

Other changes:

• #1052: Improve encoding performance when the AddCaller and AddStacktrace options are used together.

Thanks to @aerosol and @Techassi for their contributions to this release.

Enhancements:

• #989: Add EncoderConfig.SkipLineEnding flag to disable adding newline characters between log statements.
• #1039: Add EncoderConfig.NewReflectedEncoder field to customize JSON encoding of reflected log fields.

Bugfixes:

• #1011: Fix inaccurate precision when encoding complex64 as JSON.
• #554, #1017: Close JSON namespaces opened in MarshalLogObject methods when the methods return.
• #1033: Avoid panicking in Sampler core if thereafter is zero.

Other changes:

• #1028: Drop support for Go < 1.15.

Thanks to @psrajat, @lruggieri, @sammyrnycreal for their contributions to this release.

Fixed

• #1001: JSON: Fix complex number encoding with negative imaginary part. Thanks to @hemantjadon.
• #1003: JSON: Fix inaccurate precision when encoding float32.