Pranay Prakash
6cc851c342
The only thing a World does with `eventCount` is bump-and-report: when the write lands above the position named, it reads the events in between and returns them so the writer can merge them without a second round-trip. The replay loop and the suspension handler merge that page into their loaded log. The step executor has no log to merge into, so it took the page's highest position and discarded the rest. In production that discarded read fell on a third of all `step_started` writes (10.8M of 13.4M skipped-slot report reads per day were on executor event types), each a strongly consistent DynamoDB query on the run partition with resolved refs, on the response path. This removes the executor's `knownSlot` / `observeSlot` machinery, the `slotSnapshot` executor param, and the `batchCommittedSlotCeiling` the suspension handler computed only to seed it. The loop's and the suspension handler's own snapshots are unchanged; they consume their reports. The World contract already describes omitting the count for a caller with no loaded log to be stale against; the executor now matches it. Co-authored-by: Claude Fable 5.1 <noreply@anthropic.com>
@workflow/world
Core interfaces and types for Workflow SDK storage backends.
This package defines the World interface that abstracts workflow storage, queuing, authentication, and streaming operations. Implementation packages like @workflow/world-local and @workflow/world-vercel provide concrete implementations.
Used internally by @workflow/core and world implementations. Should not be used directly in application code.
Implementation constraint: no mutable module state
A World implementation must not keep mutable state at module scope. Hold it on
the World instance, or, when it is genuinely process-wide (an ID generator
whose sequence must not fork, a log-once latch), on globalThis via
globalSingleton() from @workflow/utils.
@workflow/world-local and @workflow/world-vercel are bundled into the host
application's server build, and a bundler keys module identity on
(resource, layer): Next.js alone compiles instrument, app-route, ssr and
edge as separate module graphs, so one process holds one copy of every module
in these packages per layer. A top-level let, or a const holding a Map,
is therefore per-copy state rather than the singleton it reads as.
A world loaded at runtime through WORKFLOW_TARGET_WORLD is deduped by Node's
module cache and does not have this problem today, but that is a property of
how it is loaded, not of how it is written, and it has changed before
(vercel/workflow#3493). scripts/lint/module-scope-state.mjs enforces the rule
across every published world package; see
docs/content/worlds/*/building-a-world.mdx for the author-facing version.