Implemented timers created for activity and workflow retries

[acroca]

When a timer is created to perform an activity or a workflow retry, we set a specific timer origin to the timer.

In the case of workflow retry timers, the timer origin points always to the instance ID of the first attempt

[JoshVanL]

Can this be a pointer instead to check for nil or not worth/not able to do?

[acroca]

options.instanceID is already a string, I wouldn't change that, at least not in this PR

[Copilot]

Pull request overview

This PR extends timer metadata so timers created as part of activity retries and child workflow retries carry a specific “origin” payload, and for child-workflow retry timers the origin consistently points to the first attempt’s instance ID.

Changes:

• Add new timer-origin variants for ActivityRetry and ChildWorkflowRetry and propagate them from CreateTimerAction into TimerCreatedEvent.
• Update orchestration retry logic to set the appropriate timer origin when creating retry-delay timers.
• Add/extend tests covering the new timer-origin behavior (including the “points to first child attempt” rule) and centralize child instance ID generation via a helper.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
task/orchestrator.go	Sets timer origins for retry-delay timers; refactors timer creation to allow origin mutation.
backend/runtimestate/applier.go	Maps CreateTimerAction.Origin to TimerCreatedEvent.Origin; uses helper for deterministic child instance IDs.
api/helpers/task.go	Introduces helper to generate deterministic child workflow instance IDs.
tests/runtimestate_test.go	Adds unit-style tests validating retry timer origins and first-attempt instance ID semantics.
tests/orchestrations_test.go	Adds end-to-end test for child workflow retries with auto-generated instance IDs.
api/protos/orchestrator_actions.pb.go	Generated updates to support new timer origin oneof variants in actions.
api/protos/history_events.pb.go	Generated updates to support new timer origin oneof variants in history events.

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[Copilot]

GenerateChildWorkflowInstanceID truncates the hex representation to the last 4 digits (via hex = hex[len(hex)-4:]). For action IDs >= 0x10000 this wraps/collides (e.g., 0 and 65536 both become "0000"), which can produce duplicate child workflow instance IDs and break de-duplication/correlation. Preserve the full hex value while still left-padding to at least 4 characters (e.g., %04x formatting without truncation, or manual zero-padding when len(hex) < 4).

Suggested change

	"reflect"
	"runtime"
	"strconv"
	"strings"
	)
	// GenerateChildWorkflowInstanceID generates a deterministic instance ID for a
	// child workflow based on the parent instance ID and the action's sequence number.
	func GenerateChildWorkflowInstanceID(parentInstanceID string, actionID int32) string {
	// Adding 0x10000 guarantees at least 5 hex digits (e.g. 0 → "10000"),
	// so taking the last 4 gives a zero-padded result (e.g. "0000").
	hex := strconv.FormatInt(0x10000+int64(actionID), 16)
	hex = hex[len(hex)-4:]
	"fmt"
	"reflect"
	"runtime"
	"strings"
	)
	// GenerateChildWorkflowInstanceID generates a deterministic instance ID for a
	// child workflow based on the parent instance ID and the action's sequence number.
	func GenerateChildWorkflowInstanceID(parentInstanceID string, actionID int32) string {
	// Format with a minimum width of 4 hex digits while preserving the full value
	// for action IDs that require more than 4 digits.
	hex := fmt.Sprintf("%04x", actionID)

[acroca]

cc @JoshVanL :D

[JoshVanL]

:)