go/src/encoding, branch makepkg

encoding/json: realign struct encodeState, structFields, and field

2026-02-03T11:04:30Z

This reduce the struct encodeState size from 56 to 16 bytes (-42), struct structFields size from 40 to 24 bytes (-16), and struct field size from 136 to 128 bytes (-8). Benchmark memory profiling before and after, File: json.test Type: alloc_space Time: Jan 25, 2024 at 4:51am (WIB) Showing nodes accounting for -4.01GB, 4.66% of 85.95GB total Dropped 64 nodes (cum <= 0.43GB) flat flat% sum% cum cum% -4.25GB 4.94% 4.94% -4.01GB 4.67% encoding/json.Marshal 0.19GB 0.22% 4.73% 0.24GB 0.28% encoding/json.mapEncoder.encode 0.05GB 0.057% 4.67% 0.05GB 0.057% reflect.copyVal 0.04GB 0.049% 4.62% 0.04GB 0.049% bytes.growSlice -0.04GB 0.045% 4.66% -0.04GB 0.045% encoding/json.RawMessage.MarshalJSON 0 0% 4.66% 0.04GB 0.046% bytes.(*Buffer).WriteString 0 0% 4.66% 0.04GB 0.049% bytes.(*Buffer).grow 0 0% 4.66% -0.04GB 0.045% encoding/json.(*Encoder).Encode 0 0% 4.66% 0.20GB 0.23% encoding/json.(*encodeState).marshal 0 0% 4.66% 0.20GB 0.23% encoding/json.(*encodeState).reflectValue

encoding/json: realign struct UnmarshalTypeError and decodeState

2026-02-03T11:04:30Z

This reduce the UnmarshalTypeError size from 64 to 56 bytes (-8 bytes), and decodeState from 128 to 96 (-32 bytes).

encoding/json: optimize isValidNumber function

2026-02-03T11:04:30Z

Instead of re-slicing the string for checking the value, use single index variable. Benchmark result, name old time/op new time/op delta NumberIsValid-8 19.0ns ± 0% 14.5ns ± 1% -23.70% (p=0.008 n=5+5) name old alloc/op new alloc/op delta NumberIsValid-8 0.00B 0.00B ~ (all equal) name old allocs/op new allocs/op delta NumberIsValid-8 0.00 0.00 ~ (all equal) Change-Id: I4698c5db134998f83ff47fb3add6a04ba6ec3aa0

encoding/json: use pooled encoder in Encoder.Encode

2026-02-02T21:05:45Z

Due to the lack of MarshalWrite in the v1 API, it is unfortunately common to see: json.NewEncoder(out).Encode(in) where a single-use Encoder is constructed and thrown away. This performed acceptably in v1 since every call to Encode used a globally pooled encoder resource. Prior to this change, the v1-in-v2 implementation relied on a bytes.Buffer cached only for the lifetime of the Encoder object itself. Thus, a single-use Encoder does not benefit. Modify the wrapper implementation to use the internal pooled encoder from v2 and use the intermediate buffer to write directly to the output io.Writer. We assume that the user-provided io.Writer never leaks the buffer, but this assumption was already held in the v1 implementation. We are not increasing the surface area of data corruption risk. Performance of v1 to v1-in-v2 (before the pool fix): name old time/op new time/op delta NewEncoderEncode-32 30.2ms ± 4% 28.3ms ± 9% -6.19% (p=0.002 n=9+10) name old alloc/op new alloc/op delta NewEncoderEncode-32 7.64MB ± 0% 28.37MB ± 0% +271.23% (p=0.000 n=10+10) name old allocs/op new allocs/op delta NewEncoderEncode-32 200k ± 0% 100k ± 0% -49.99% (p=0.000 n=9+10) Interestingly, v1-in-2 is slightly faster, but the amount of allocated memory is massive. Performance of v1 to v1-in-v2 (after the pool fix): name old time/op new time/op delta NewEncoderEncode-32 30.2ms ± 4% 24.0ms ± 7% -20.36% (p=0.000 n=9+10) name old alloc/op new alloc/op delta NewEncoderEncode-32 7.64MB ± 0% 4.09MB ± 3% -46.52% (p=0.000 n=10+10) name old allocs/op new allocs/op delta NewEncoderEncode-32 200k ± 0% 100k ± 0% -50.00% (p=0.000 n=9+9) Now, the v1-in-v2 implementation is better than v1 on all metrics. Fixes #75026 Change-Id: I50c975b1d5b8da806e46bc627966b0a39c1817eb Reviewed-on: https://go-review.googlesource.com/c/go/+/740660 Reviewed-by: Michael Pratt Reviewed-by: Damien Neil LUCI-TryBot-Result: Go LUCI

cmd/go,crypto/mlkem,crypto/x509,encoding/ascii85: clean up tautological/impossible nil conditions

2026-01-30T15:54:05Z

Change-Id: I3cdc599ebc93f5c9be5645e7ef7ce167242d9c1b Reviewed-on: https://go-review.googlesource.com/c/go/+/739800 Reviewed-by: Roland Shoemaker LUCI-TryBot-Result: Go LUCI

encoding/json: fix typo in package doc.

2026-01-24T02:08:03Z

Change-Id: Id5520757e4d73e56e533e4de4f5f303105c4339e Reviewed-on: https://go-review.googlesource.com/c/go/+/738180 Reviewed-by: Dmitri Shuralyov Auto-Submit: David Symonds Reviewed-by: Carlos Amedee Reviewed-by: David Symonds Reviewed-by: Ian Lance Taylor Reviewed-by: Joseph Tsai LUCI-TryBot-Result: Go LUCI

encoding/json: remove unneeded unsafe import

2026-01-22T22:29:44Z

Followon for CL 721160. Change-Id: I9c22c5e99c9084e24047c77d20717c5b46165cde Reviewed-on: https://go-review.googlesource.com/c/go/+/732220 Reviewed-by: Carlos Amedee Reviewed-by: Michael Pratt Reviewed-by: Sean Liao LUCI-TryBot-Result: Go LUCI

encoding/json/v2: remove issue reference in Duration formatting error

2026-01-22T15:31:33Z

The json/v2 working group decided to commit to no default representation for time.Duration for the foreseeable future. Thus, we can remove the issue reference in the error message. If JavaScript (TC39) formally adopts the Temporal.Duration type, which uses ISO 8601 as the JSON representation for a duration, we may consider changing the default. Switching from no default to some default in the future is generally a compatible change. Updates #71631 Change-Id: I6f71a0fa97dcefba56aab0c0ddf445d9d38f6e58 Reviewed-on: https://go-review.googlesource.com/c/go/+/735080 Reviewed-by: Michael Pratt Reviewed-by: Damien Neil Auto-Submit: Joseph Tsai LUCI-TryBot-Result: Go LUCI

encoding/gob: clarify docs about pointers to zero values not being sent

2025-12-29T20:45:08Z

The documentation on encoding/gob mentions that pointers are flattened, and it also explicitly says that empty values are not sent. A corollary of this, is that pointers to zero values are not sent, i.e., gob-encoding of *false becomes nil on the receiver side. It is worth documenting this explicitly. Change-Id: I1909203b8972e20791144bdda22e5f1b466aad97 GitHub-Last-Rev: 57764ec235ffe48484be98d3ed5269f0102ca4f8 GitHub-Pull-Request: golang/go#77009 Reviewed-on: https://go-review.googlesource.com/c/go/+/732820 Reviewed-by: Roland Shoemaker Reviewed-by: Rob Pike LUCI-TryBot-Result: Go LUCI Reviewed-by: Sean Liao Reviewed-by: Cherry Mui

encoding/json/jsontext: add symbolic Kind constants

2025-12-11T17:37:03Z

Add constants for each possible Kind value (KindNull, KindTrue, etc.). Leave the values unchanged ('n', 't', etc.). Update documentation to reference the symbols. Fixes #71756 Change-Id: Ib33b2ad9ee55f6f547d9e6a1c5a7f00c8400d3d3 Reviewed-on: https://go-review.googlesource.com/c/go/+/728420 Auto-Submit: Damien Neil Reviewed-by: Joseph Tsai Reviewed-by: Dmitri Shuralyov LUCI-TryBot-Result: Go LUCI