Files
buzz/schema/tables/public/channels.sql
Logan Johnson 2f79374f48 feat(relay): channel labels (#8175)
🤖
## Summary
A plugin or agent often needs to tag its own channels and then find them
again, for example "my attention-config channel" or "all channels of
this workspace". Today a channel has no labels: the relay ignores any
`t` tags in create or edit requests. This PR adds channel labels.

- A create request can carry up to 8 labels as `["t", "<label>"]` tags.
- An edit request with `t` tags replaces the label set. `["t", ""]`
alone clears it, the same convention as `["ttl", ""]`. Only owners and
admins can change labels, as for the name.
- The relay publishes each label as a `t` tag on the channel's state
events, after the channel type tag.

Part 2 of 3, stacked on part 1.

### Related issue
None found.

### Details
- **Rules.** A label uses 1–64 characters from `a-z`, `0-9`, `.`, `:`
and `-`. The relay refuses a label equal to a channel type name
(`stream`, `forum`, `dm`, `workflow`, `system`), so a label cannot make
a channel look like another type.
- **No trust from labels.** Any admin can set a label. Only the
relay-written creator tag (part 1) says who made a channel.
- **Storage.** New migration `0061_channel_labels.sql` adds
`channels.labels TEXT[] NOT NULL DEFAULT '{}'`. Channels without labels
look and behave as before.
- **Readers.** The CLI and `buzz-acp` read the channel type from the
first `t` tag. Before this PR they used the last one, which would now be
a label.
- **Spec.** NIP-CL gets a "Channel labels" section with these rules.

### Testing
- Relay tests: labels at creation appear after the type tag, edit
replaces and clears them, invalid labels are refused, and members who
are not admins cannot change them.
- Unit tests for the label rules: allowed characters, length, reserved
type names, the 8-label cap and the clear marker.
- `buzz-acp` test: the channel type comes from the first `t` tag, not a
label.

### Stack
These are two stacks. Merge them in this order. Client support
(creating, labeling and finding these channels) will be in
block/buzz-app, not the buzz SDK and CLI.

**Stack 1: channel labels and creator lookup (#8174–#8176)**

1. #8174 channel type and creator tags, and the channel creation time
2. #8175 channel labels ← this PR
3. #8176 database-side label and creator match, and the rule for
choosing one channel

**Stack 2: system channels (#8180–#8182)**, stacked on stack 1 because
it uses labels and the creator tag

4. #8180 the system channel type
5. #8181 leave system channels out of reads that do not name them
6. #8182 channel-state filters opt in to system channels

---------

Signed-off-by: Logan Johnson <loganj@squareup.com>
Co-authored-by: Larry <627498bd4bd1f281a16431e3c6cce3b5c25b6692798c78672298aefbf2f8f8b5@buzz.block.builderlab.xyz>
2026-10-14 17:25:46 -04:00

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SQL

-- ── Channels ──────────────────────────────────────────────────────────────────
-- Conformance: "Channels and channel membership". `community_id` immutable.
-- Channel UUIDs stay valid wire identifiers, but they are NOT globally unique:
-- the PK is `(community_id, id)`, so the same UUID may legitimately exist in two
-- communities (conformance lists "same channel UUID collision in two
-- communities" as a required isolation test). Handlers always carry `ctx`, so
-- `(ctx.community, h)` names exactly one channel; a client-supplied `h` can
-- never reach another community's channel.
CREATE TABLE channels (
id UUID NOT NULL DEFAULT gen_random_uuid(),
community_id UUID NOT NULL REFERENCES communities(id),
name VARCHAR(255) NOT NULL,
channel_type channel_type NOT NULL DEFAULT 'stream',
visibility channel_visibility NOT NULL DEFAULT 'open',
description TEXT,
canvas TEXT,
created_by BYTEA NOT NULL,
created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
archived_at TIMESTAMPTZ,
deleted_at TIMESTAMPTZ,
nip29_group_id VARCHAR(255),
topic_required BOOLEAN NOT NULL DEFAULT FALSE,
max_members INT,
topic TEXT,
topic_set_by BYTEA,
topic_set_at TIMESTAMPTZ,
purpose TEXT,
purpose_set_by BYTEA,
purpose_set_at TIMESTAMPTZ,
participant_hash BYTEA,
ttl_seconds INT,
ttl_deadline TIMESTAMPTZ,
-- Labels, published as ["t", <label>] after the channel type tag on the
-- relay-signed group-state events. The relay validates their shape.
labels TEXT[] NOT NULL DEFAULT '{}'
CONSTRAINT channels_labels_bounded CHECK (cardinality(labels) <= 8),
PRIMARY KEY (community_id, id),
CONSTRAINT chk_channels_id_not_nil CHECK (id <> '00000000-0000-0000-0000-000000000000'::uuid)
);
-- nip29 group id and DM participant hash are unique WITHIN a community, not globally.
CREATE UNIQUE INDEX idx_channels_nip29_group ON channels (community_id, nip29_group_id)
WHERE nip29_group_id IS NOT NULL;
CREATE UNIQUE INDEX idx_channels_dm_hash ON channels (community_id, participant_hash)
WHERE participant_hash IS NOT NULL;
CREATE INDEX idx_channels_community_type ON channels (community_id, channel_type);
CREATE INDEX idx_channels_community_visibility ON channels (community_id, visibility);
CREATE INDEX idx_channels_created_by ON channels (community_id, created_by);
CREATE INDEX idx_channels_ttl_expiry ON channels (ttl_deadline)
WHERE ttl_seconds IS NOT NULL AND archived_at IS NULL AND deleted_at IS NULL;
-- Tenant-independent channel-id → community lookups (Db::communities_of_channels,
-- Db::community_of_channel) carry no community_id predicate, so no
-- community_id-leading index can serve them. Covering + partial: index-only scan.
-- Not UNIQUE — the same channel id may exist under more than one community.
CREATE INDEX idx_channels_id_live ON channels (id) INCLUDE (community_id)
WHERE deleted_at IS NULL;