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Summary

quarry names the things that happen in a repository, once, in a vocabulary that pipelines, webhooks and notifications all subscribe to. An event is a noun and an action — ticket.closed, landing.opened, branch.created — carried on the bus that already exists, with a payload shape declared per noun.

Today there are two and a half paths and no vocabulary. Webhooks derive an event's kind by slicing a notification's idempotency string. CI does not use events at all: it polls the index for new check-ins behind a per-repository watermark. Notifications have their own workflow names. Adding one more trigger — a landing opening, say — means either a third path or generalising anyway, so this RFC generalises first.

The vocabulary is the load-bearing part, and the reason this is an RFC rather than a commit: a pipeline definition names events in its on: clause, so an event name is a published interface. Renaming one breaks every pipeline in every repository that used it, in a system where the pipeline definition is itself a versioned artifact in someone else's store.

Motivation

What exists

ci.Trigger runs after every fold. It asks the index for check-ins newer than a watermark, reads ci/*.json at each one, registers the definition at that check-in, and starts a run. pollCI later polls unfinished runs and, on a terminal status, mints a ci-pass / ci-fail tag on the check-in.

That is a complete, working pipeline trigger for exactly one event, with the event's identity left implicit. Four things in it are check-in-shaped:

today needed
trigger poll NewCheckins(watermark) subscribe to a named event
payload {repo, checkin, branch, date, user, comment, cloneUrl, pipeline} per-noun, common envelope
watermark one check-in per repository per subscription
verdict sink WriteTag(verdict, checkin, runID) per-noun; a landing wants a reply

Every one of those blocks the landing trigger (quarry ticket 49323c33), and none of them is made easier by doing the landing trigger first.

What the field does

Four vocabularies were read before proposing a fifth.

Fossil hooks (www/hooks.md) are artifact-level and carry no semantics at all. Three types — after-receive, before-commit, commit-msg — and the after-receive hook's stdin is a list of artifact hashes with human-readable descriptions. There is no "on branch created" or "on merge". The doc states its purpose plainly: to "start up a background testing or CI process".

Fossil alerts (src/alerts.c) carry fossil's only semantic vocabulary, as subscription letters on the subscriber.ssub column:

a Announcements          c Check-ins            f Forum posts
n New forum threads      r Replies to my posts  t Ticket changes
u User permission changes  w Wiki changes       x Edits to forum posts

Eight types. It splits the forum four ways by verb, and has no event for a branch, a tag, a technote or a merge.

GitHub publishes 75 webhook events, most of which are not about version control: roughly six VCS core, fifteen collaboration, eight CI, ten security scanning, fifteen governance, and twenty platform and commerce events (marketplace, sponsorships, apps, Pages, Projects). quarry has a concept for about twenty of them. Gitea publishes about 27, GitLab 15.

The shape decision

The three forges disagree about the axis, and the disagreement is the design question:

quarry takes GitHub's. Under Gitea's rule every new verb is a new permanent event name, and the name is a published interface. Under GitHub's, a subscriber can ask for ticket and get every change, or ticket.closed and get one, and adding a verb later costs nothing. Fossil's split shows the cost of the other choice inside one product: f and n and x are three names for three verbs on one noun, and a subscriber who wants "any forum activity" must name all three and remember to add the fourth when it appears.

Guide-level explanation

An event is noun.action. A subscriber names either the whole noun or one action of it:

"on": ["checkin.created"]                  one action
"on": ["ticket"]                           every action on the noun
"on": ["landing.opened", "landing.reopened"]

A pipeline with no on: clause runs on checkin.created, which is today's behaviour exactly, so every pipeline already in a repository keeps working without being edited.

Every event carries the same envelope, and a payload keyed by its noun:

{
  "event":  "landing.opened",
  "repo":   "quarry",
  "at":     "2026-08-24T09:48:57.123",
  "actor":  "dmestas",
  "id":     "activity:landing:9802c157…",
  "payload": { "landing": "9802c157…", "branch": "wiki-struct", "target": "trunk" }
}

id is the idempotency key. It is stable for one occurrence of one event, and it is how a consumer that sees an event twice can tell that it has.

Reference-level explanation

§1 The vocabulary

Nouns and their actions. An action marked † is not yet raised by any code path and is reserved so that adding it later is not a vocabulary change.

noun actions payload
checkin created hash, branch, parents, user, comment
branch created, moved, closed† name, tip, previous tip
tag created, removed† name, target, value
ticket opened, changed, closed, reopened id, title, fields changed
wiki edited, created, deleted title, hash
technote created, edited event id, hash
forum posted, replied, edited†, moderated thread root, post hash
landing opened, commented, accepted, rejected id, branch, target
ci started, completed run id, checkin or landing, verdict
mirror pulled, failed url, artifacts received
repo created, removed, settings name
account added, caps, removed account, repository, caps

Fourteen nouns, thirty-odd actions. For comparison: fossil's alerts name eight things, GitHub's 75 events name about twenty that quarry has a concept for.

Three of these exist in no other forge, and are here because quarry has the concept and an operator needs the hook: technote (fossil has the artifact but no alert for it), mirror (a forge that tracks 25 upstreams needs to fire on a failed pull), and landing.

§2 Delivery semantics, which the medium decides

Fossil's hook documentation states the constraint, and quarry inherits it rather than choosing it:

A push might not deliver all of the artifacts for a checkin. If Fossil knows that a /xfer HTTP request is incomplete, it will defer running the after-receive push for 60 seconds, or until a complete /xfer request is received. This helps to prevent after-receive hooks from running when incomplete checkins exist in the repository, but it does not provide hard guarantees, as there is no way to do that in a distributed system.

So:

  1. At-least-once. A consumer may see an event twice. id is the idempotency key and a consumer that acts on an event MUST be idempotent under it. quarry's own notification plane already works this way.
  2. Possibly batched. Fossil warns that two pushes' artifacts "might be combined into a single after-receive callback". quarry's fold has the same property; a single fold can produce many events, and a consumer must not assume one event per delivery.
  3. Possibly partial. An event may describe state that is still arriving. A consumer that needs the whole picture reads the index at handling time rather than trusting the payload to be complete.
  4. Ordered within a repository, not across. The bus preserves order per repository because the fold does; nothing orders two repositories against each other, and nothing should be written that needs it.

§3 Handlers do not run inside the fold

Fossil again:

Fossil holds a write transaction on the repository while the after-receive hook is running.

A hook that writes to the repository it was fired by therefore deadlocks. The same is true here for a different reason: quarry mints artifacts through the lease holder, and the fold is not it.

An event handler that mints an artifact runs outside the fold, through the lease holder, asynchronously. The CI verdict already obeys this by accident of structure — pollCI runs on a timer, not in the ingest path. This RFC makes it a rule rather than an accident, because the landing verdict (700b22b6) would otherwise be written from exactly the wrong place.

§4 One stream, three consumers

consumer today after
webhooks Raise() from fireNotify, kind sliced out of a TxnID subscribes by name
CI polls NewCheckins behind a watermark subscribes by name
notifications own workflow names subscribes by name

The watermark does not disappear: it becomes per-subscription rather than per-repository, because two consumers may be at different positions and one falling behind must not advance the other.

§5 Verdict sinks

A CI run's verdict is an artifact, because 0001 §6's no-hostage rule says the result must clone with the repository. Which artifact depends on the noun that triggered it:

The rule generalises: the verdict takes the shape of the thing it judges.

§6 What is deliberately absent

Named so the absence reads as a decision rather than an oversight:

The last one is the one most likely to be asked for later. It should be its own RFC, and it should not reuse these names.

Drawbacks

A published vocabulary is hard to change. That is the point, and also the cost: a name chosen badly here is one every pipeline in every store repeats. The mitigation is the reserved actions in §1 and the noun-plus-action shape, which absorbs new verbs without new names.

One stream is a single point of failure where today CI's polling is independently robust: if the bus stops, CI stops. The watermark survives, so nothing is lost, but a stalled bus becomes a stalled forge in a way a stalled poll loop is not. §2's at-least-once rule and per-subscription watermarks are what make recovery a replay rather than a repair.

Fourteen nouns is more than fossil has and fewer than GitHub. Both comparisons will be made, and neither is the argument: the set is what quarry can honestly raise today plus what it will raise next.

Rationale and alternatives

Do the landing trigger without a vocabulary. Rejected: all four generalisations in the motivation table are needed for it anyway, and the result is a third trigger path. Ticket 49323c33 says so in its own words — "rides the existing event plane … rather than growing a second trigger path".

Adopt fossil's after-receive shape: hand the handler a list of artifacts. Rejected. It is honest and it is what fossil does, but it pushes the whole interpretation problem to every consumer: each pipeline would re-derive "is this a new branch" from artifact hashes, and they would derive it differently. quarry already folds artifacts into meaning; the event stream should carry the meaning it already has.

Adopt Gitea's noun_verb naming. Rejected in §Motivation: every new verb becomes a permanent name.

Use GitHub's names verbatim where they overlap. Tempting for recognisability, and rejected in two places: issues is called ticket here because that is what fossil calls it and fossil compatibility is the north star, and pull_request is called landing because it is not one — nothing is transported and nobody requests a pull (zit#127).

Prior art

Unresolved questions

  1. Does branch.moved fire per check-in or per fold? A ten-commit push moves the branch once but creates ten check-ins. Firing per fold makes branch.moved cheap and coarse; firing per check-in makes it redundant with checkin.created. Leaning per fold, with the check-in count in the payload.
  2. Should ci.completed be subscribable? It would let a pipeline trigger on another pipeline, which is either composition or a foot-gun. GitHub allows it (workflow_run) and guards against recursion. Deferred until something needs it.
  3. How does a subscription express "my repository only" versus fleet-wide? The webhook plane is per-repository today; CI is per-repository; a fleet-wide subscriber (an operator watching mirror.failed across 25 stores) has no way to say so.
  4. JetStream delivery guarantees have not been traced. §2 states what the vocabulary promises; whether the current bus configuration delivers it — durable consumers, redelivery, cursor persistence across restarts — is unverified and must be before CI moves off polling.

Future possibilities