align default identity tags with .NET

[Tomer Rosenthal (torosent)]

Go repeats owning-orchestration identity in activity, sub-orchestration, and ContinueAsNew tag maps even when the caller supplies no tags. Remove that payload and use native protocol identity fields, matching .NET's automatic-tag behavior.

Behavior

Activities expose their own name/version/task ID and the owning instance ID. Orchestrator contexts obtain their full identity from native history fields. There is no identity-tag encoder, decoder, or richer-identity activity option.

Caller tags, Go activity-tag inheritance, immutable context fields, namespace isolation, and trace fields are preserved. Alignment is specifically automatic identity tags, not all SDK tag features or caller-tag wire formats.

Verified against .NET main 8f1b135: scheduling, gRPC serialization, activity context, and pinned Core 3.9.0 history/tag propagation.

Validation

Local go test ./..., affected-package race tests, go build ./..., and go vet ./... pass with DTS/Azurite/sample targets unset. Coverage includes caller-data isolation, replay/redelivery, cancellation/retries, and native child/ContinueAsNew identity.

Fixed public protobuf fixture, previous → current: action 331 → 85, scheduled history 342 → 95, activity request 343 → 97 bytes. The previous payload exists only as a benchmark fixture. Reproduce with go test ./task -run TestActivityIdentitySerializedSize -v or -run '^$' -bench BenchmarkActivityIdentityWireSize. These are serialization sizes, not storage/WAL or throughput measurements.

[Copilot]

Copilot review overview

🟢 Approval recommended

The scoped behavior change has a documented migration path and focused compatibility coverage, with no unresolved review findings.

Review effort: Balanced
Findings: None

What changed in this PR

Aligns Go’s default automatic identity tags with .NET by omitting redundant orchestration identity while preserving an explicit activity opt-in.

Changes:

• Removes default identity tags from activities, sub-orchestrations, and ContinueAsNew.
• Adds task.WithActivityOrchestrationIdentity() and documents migration.
• Adds compatibility, replay, retry, and serialized-size coverage.

File	Description
task/​versioning_test.go	Updates tag validation and ContinueAsNew expectations.
task/​tag_identity_test.go	Covers identity defaults, opt-in, replay, and retries.
task/​tag_identity_bench_test.go	Measures serialized identity-tag overhead.
task/​orchestrator.go	Makes activity identity optional and removes other default identity tags.
task/​context_test.go	Updates encoding calls and historical identity fixtures.
task/​activity.go	Adds the activity identity opt-in option.
README.md	Explains new defaults and migration.
internal/​contextprop/​tags.go	Allows encoding without orchestration identity.
internal/​contextprop/​tags_test.go	Tests optional identity, legacy formats, and data isolation.
CHANGELOG.md	Records behavior changes and compatibility guarantees.
api/​context.go	Documents activity identity availability.

---

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.

[Copilot]

Copilot review overview

🟡 Changes recommended

Historical activity identity decoding must be preserved, and the promised identity opt-in API is missing.

Review effort: Balanced
Findings: 2

Open (2)

• Restore legacy activity orchestration identity decoding · New
• Add opt-in orchestration identity for activity scheduling · New