feat!: v0.3.0 — Err / ErrAny return single inline zap.Field

[maxence2997]

Summary

BREAKING CHANGE. Err(err) and ErrAny(v) now return a single zap.Field (inline) instead of []zap.Field. Output JSON is unchanged — same flat dotted ECS keys.

Why

Surfaced from streaming-observer dogfooding (O4 in the v0.2.0 dogfood report):

The []zap.Field return type forces callers to break inline log call style and fight with prealloc lint:

// v0.2.0 — awkward
fields := make([]zap.Field, 0, 5)
fields = append(fields, ecsf.ServiceName("auth"), ecsf.EventAction("login"))
fields = append(fields, ecsf.Err(err)...)
logger.Error("failed", fields...)

// v0.3.0 — inline
logger.Error("failed",
    ecsf.ServiceName("auth"),
    ecsf.EventAction("login"),
    ecsf.Err(err),
)

v0.x allows breaking changes, so the cleaner API wins over a parallel ErrField helper that would split the API surface.

How

• Err(err) zap.Field returns zap.Inline(errMarshaler{err: err}) — a single Field whose MarshalLogObject writes error.message / error.type / error.stack_trace directly into the encoder.
• ErrAny(v) zap.Field mirrors the structure with errAnyMarshaler (handles typed-nil, non-error fallback, then delegates to errMarshaler).
• Both return zap.Skip() when input is nil — the field is no-op when added, so unconditional inline use is safe.
• zap.Inline flattens the marshaler's keys at the current namespace, so output is identical to the v0.2.0 multi-field shape (no nesting, no dot/object difference).

Test plan

• make check passes (fmt + lint + race-detector test)
• All 14 error tests rewritten to assert against zapcore.NewMapObjectEncoder output (which zap.Inline flattens into via AddTo)
• Tests cover: nil → Skip, plain error, samber/oops StackTracer, pkg/errors StackTracer, string/int/struct (ErrAny non-error), typed-nil error (no panic)
• CI green

[Copilot]

Pull request overview

This PR introduces a breaking API change in the zap/ subpackage: Err(err) and ErrAny(v) now return a single inline zapcore.Field (via zap.Inline) instead of []zapcore.Field, while keeping the emitted ECS error.* keys and flat JSON output shape the same.

Changes:

• Refactor Err / ErrAny to return a single inline zapcore.Field backed by zapcore.ObjectMarshaler.
• Rewrite error tests to assert emitted encoder output (via zapcore.NewMapObjectEncoder) rather than inspecting field slices.
• Update example + docs + changelog to reflect the new inline-call style and zap.Skip() nil behavior.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
zap/error.go	Switch Err/ErrAny to zap.Inline + marshalers, and return zap.Skip() on nil input.
zap/error_test.go	Update tests to validate encoded output for inline fields and skip behavior.
example/main.go	Update example usage to pass ecsf.Err(err) inline (no slice append/splat).
docs/related-projects.md	Adjust guidance table to remove ... splat usage for Err/ErrAny.
docs/ecs-coverage.md	Update coverage notes to reflect new return types and inline behavior.
CHANGELOG.md	Document the breaking change and provide migration snippet.

[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Comments suppressed due to low confidence (1)

zap/error.go:56

• The Err doc comment says error.message is always err.Error(), but typed-nil errors intentionally emit error.message = "<nil>" without calling Error(). Consider adjusting the bullet list to reflect this exception so the docs match the actual behavior.

// Err returns a single inline zap.Field that emits ECS error.* fields:
//
//   - error.message: always (err.Error())
//   - error.type:    always (fmt.Sprintf("%T", err))
//   - error.stack_trace: if any error in the chain implements one of the

[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated no new comments.