Pre-RFC-#2945, every BroadcastOnly / RecordAndBroadcast call site
passed a bare string literal:
h.broadcaster.BroadcastOnly(workspaceID, "AGENT_MESSAGE", payload)
29 producers (Go, ~30 call sites in handlers/, scheduler/, registry/,
bundle/) and ~30 canvas consumers (TS store + listeners) duplicated
the same string with no shared definition. A producer renaming an
event silently broke every consumer — same drift class that produced
the reno-stars data-loss regression on the persistence side. PR-A
fixed the persistence-side SSOT (AgentMessageWriter); PR-B fixes the
event-name SSOT.
What this PR ships
internal/events/types.go
- EventType typed string + 29 named constants covering the full
taxonomy (chat / lifecycle / agent assignment / delegation /
task / approval / auth).
- Grouped semantically; new constants must be added here AND
mirrored in canvas/src/lib/ws-events.ts (parity gate landing
in PR-B-2 follow-up).
- AllEventTypes slice — authoritative list for the snapshot
test + the cross-language parity gate.
internal/events/types_test.go (3 tests)
- TestAllEventTypes_IsSnapshot: pins the canonical list. Adding
a new constant without updating AllEventTypes (or vice versa)
fails with a one-line diff.
- TestEventType_NoEmptyConstants: catches accidentally-empty
values (typo in types.go: const X EventType = ...).
- TestEventType_AllUppercaseSnakeCase: pins the wire format that
canvas TS switch statements assume (no kebab-case, no mixed
case, no leading/trailing/double underscores).
agent_message_writer.go (single migration)
- Demonstrates the constant-usage shape:
events.EventAgentMessage → "AGENT_MESSAGE"
- Other ~30 call sites stay on bare strings for now (this PR
narrow); the migration happens in PR-B-1 follow-up. Both
shapes (constant + bare string) co-exist on the wire — the
typed version is just the recommended path for new code.
Why ship this in stages
1. PR-B (this): types + tests + first migration → MERGEABLE NOW,
low risk.
2. PR-B-1 (follow-up): migrate the remaining ~30 call sites to
constants. Mechanical, low-risk.
3. PR-B-2 (follow-up): canvas/src/lib/ws-events.ts mirror + cross-
language parity gate. Touches both repos.
Per memory feedback_oss_design_philosophy.md (every refactor toward
OSS plugin shape) — this surface is now plugin-safe: external
implementations can import the events package and get the same
named taxonomy without copying strings.
Verified
- go vet ./internal/events/ clean
- go build ./... clean
- TestAllEventTypes_IsSnapshot + TestEventType_* all pass
- TestAgentMessageWriter_* (the only call site touched) still green
Refs RFC #2945, PR #2949 (PR-A SSOT), PR #2944 (reno-stars).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
The 3 skipped tests in workspace_provision_test.go (#1206 regression
tests) were blocked because captureBroadcaster's struct-embed wouldn't
type-check against WorkspaceHandler.broadcaster's concrete
*events.Broadcaster field. This PR fixes the interface blocker for
the 2 broadcaster-related tests; the 3rd (plugins.Registry resolver)
is a separate blocker tracked elsewhere.
Changes:
- internal/events/broadcaster.go: define `EventEmitter` interface with
RecordAndBroadcast + BroadcastOnly. *Broadcaster satisfies it via
its existing methods (compile-time assertion guards future drift).
SubscribeSSE / Subscribe stay off the interface because only sse.go
+ cmd/server/main.go call them, and both still hold the concrete
*Broadcaster.
- internal/handlers/workspace.go: WorkspaceHandler.broadcaster type
changes from *events.Broadcaster to events.EventEmitter.
NewWorkspaceHandler signature updated to match. Production callers
unchanged — they pass *events.Broadcaster, which the interface
accepts.
- internal/handlers/activity.go: LogActivity takes events.EventEmitter
for the same reason — tests passing a stub no longer need to
construct the full broadcaster.
- internal/handlers/workspace_provision_test.go: captureBroadcaster
drops the struct embed (no more zero-value Broadcaster underlying
the SSE+hub fields), implements RecordAndBroadcast directly, and
adds a no-op BroadcastOnly to satisfy the interface. Skip messages
on the 2 empty broadcaster-blocked tests updated to reflect the
new "interface unblocked, test body still needed" state.
Verified `go build ./...`, `go test ./internal/handlers/`, and
`go vet ./...` all clean.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
