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feat: rebuild the group's signed record out of the rows it left behind

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Phase 3 of docs/member-archive.md. `ArchiveManager.assemble` walks a room's rows,
rebuilds each into the event the group signed, drops anything it cannot prove,
and cuts the rest into pages. Nothing sends one yet.

**The gate found a real bug, which is why it was the gate.** Signed events are
not stored as events -- `FrostSigningManager.complete` applies one and what
survives is a `Mantra*` row -- so an archive has to rebuild them with `toXEvent()`
and stands or falls on that being byte-identical to what was signed. Every
`toXEvent()` in the codebase turned out to be unused in production, written for
exactly this and never called, so the "tag order matches build so the event id
round-trips" comments on them were claims nothing had ever checked.

One was wrong. `MantraArtifact.toArtifactEvent` put the alt tag last where
`ArtifactEvent.build` puts it first, and left out the version metadata tag
altogether -- because that tag is not on the artifact row at all.
`fromArtifactEvent` reads the artifact's own fields and drops the version label,
which `applyInnerEvent` has by then turned into the artifact's first
`MantraArtifactVersion`. So the label is now a parameter, read off the initial
version: the one whose `createdAt` is the artifact's, since `initialVersionOf`
derives it from the same event.

Neither fault would have surfaced as an error. Both produce a well-formed
artifact whose id no longer matches its fields, which every receiver drops as a
forgery, silently, one kind at a time. `ArchiveRoundTripTest` now signs each
archivable kind with a real quorum, files it as a row, rebuilds it and asserts
the signature still covers what comes out -- plus the negative case, that
rebuilding with the wrong version label fails as a forgery rather than as a
mistake, which is why the assembler reads the label rather than defaulting it.

**The allowlist narrows from nine kinds to six, and this is the finding to read.**
Only six of the thirteen nip30303 kinds ever reach a signing session; the rest
travel as member rumors, vouched for by the MLS frame they arrived in and by
nothing that survives leaving it. An artifact version is derived rather than
signed -- which is fine, because applying the archived artifact derives it again
and the chapters hanging off it keep their foreign key. Nothing builds a
`TranslationEvent` at all. The contributor lists have no arm in `applyInnerEvent`
that writes a row.

And `TranslationChunkEvent` -- **the translated text itself** -- is submitted by
`MantraDao.saveTranslation` as its author's rumor, because a translation is one
member's work rather than a group decision. So an archive restores everything a
translation hangs on and not the translation: a new member gets the dialects, the
artifacts, the chapters, the source chunks, which translations exist and their
chapter scaffolding, and none of the prose. That is a real limit rather than a
detail, so it is written into the allowlist's own doc comment, into the plan's
"what this does not do", and into a test named after it -- with the three ways
out sketched and none of them taken here, because the cheapest gives up the
property the rest of this rests on and the best is a product decision about
whether translating is an act of the group or of a member.

**Nothing unverifiable leaves.** Every rebuilt event is checked with
`isSignedByRoom` against the same room id the recipient will use. Not politeness
-- the receiver checks anyway -- but so the page count says what will actually
arrive: a row from a member's rumor is dropped here rather than by the recipient.

**Walked down the tree, not queried per kind.** Only dialects and artifacts have
a by-room query and the rest hang off a parent, and the walk is also what puts an
artifact's version label within reach. Order is settled afterwards by
`inApplyOrder` rather than by the walk, since the walk groups by artifact and the
foreign keys are by kind.

**Paging is greedy against both caps**, because they bind different archives: a
room of one-line dialects hits the count first and a room of chapters hits the
bytes. An event too large for a page of its own is dropped with a log rather than
failing the archive -- a chapter nobody can archive is a hole, a member who gets
nothing is a bigger one.

Assembling only; queueing moved to Phase 5, where the thing that decides when to
send lives. That keeps this testable against a real database with no outbound
path in the way.

Seven tests over a real in-memory database seeded through `applyInnerEvent`
itself, so what is archived is what a member's device really holds rather than
rows built to suit the test: every payload verifies, all six kinds appear exactly
as often as they were signed, the whole archive is in dependency order end to
end, a member's unsigned dialect sitting in the same room is left out, an empty
room archives nothing without failing, and two archives of identical rows do not
share an id -- which is what stops two members answering one request from having
their pages counted towards each other's total.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
This commit is contained in:
Kgothatso Ngako
2026-09-06 14:12:29 +02:00
parent 6e04f6c7af
commit acff66a22e
7 changed files with 1107 additions and 33 deletions
Download Patch File Download Diff File Expand all files Collapse all files

53
composeApp/src/commonTest/kotlin/press/mantra/compose/nostr/archive/ArchiveEventTest.kt
View File

@@ -179,20 +179,38 @@ class ArchiveEventTest {
// ---- What an archive may carry ---------------------------------------
@Test
fun `the allowlist is every kind an archive can restore, and only those`() {
fun `the allowlist is every kind the group signs, and only those`() {
listOf(
DialectEvent.KIND,
ArtifactEvent.KIND,
ArtifactVersionEvent.KIND,
ChapterEvent.KIND,
ChunkEvent.KIND,
TranslationArtifactVersionEvent.KIND,
TranslationChapterEvent.KIND,
TranslationChunkEvent.KIND,
TranslationEvent.KIND,
).forEach { assertTrue(ArchiveEvent.isArchivable(it), "kind $it should be archivable") }
assertEquals(9, ArchiveEvent.ARCHIVABLE_KINDS.size)
assertEquals(6, ArchiveEvent.ARCHIVABLE_KINDS.size)
}
@Test
fun `the kinds nobody signs are left out, translations included`() {
// The limit worth knowing about before reading anything else here. An
// archive can only carry what the receiver can check, and six of the
// thirteen nip30303 kinds reach a signing session. The rest travel as
// rumors -- empty signature, member author -- vouched for by the MLS
// frame they arrived in and by nothing that survives leaving it.
// The translated text. MantraDao.saveTranslation submits it as the
// member's own rumor, so an archive restores everything a translation
// hangs on and not the translation.
assertFalse(ArchiveEvent.isArchivable(TranslationChunkEvent.KIND))
// Never signed either: derived from the signed artifact on arrival, which
// is what keeps a chapter's foreign key satisfied without archiving it.
assertFalse(ArchiveEvent.isArchivable(ArtifactVersionEvent.KIND))
// Nothing builds one of these at all.
assertFalse(ArchiveEvent.isArchivable(TranslationEvent.KIND))
}
@Test
@@ -235,17 +253,18 @@ class ArchiveEventTest {
// Every one of these is a foreign key in Room, so an archive applied the
// other way round is a constraint violation rather than a wrong answer.
assertTrue(rank(DialectEvent.KIND) < rank(ArtifactEvent.KIND))
assertTrue(rank(ArtifactEvent.KIND) < rank(ArtifactVersionEvent.KIND))
assertTrue(rank(ArtifactVersionEvent.KIND) < rank(ChapterEvent.KIND))
assertTrue(rank(ChapterEvent.KIND) < rank(ChunkEvent.KIND))
assertTrue(rank(ArtifactVersionEvent.KIND) < rank(TranslationArtifactVersionEvent.KIND))
assertTrue(rank(DialectEvent.KIND) < rank(TranslationArtifactVersionEvent.KIND))
assertTrue(rank(TranslationArtifactVersionEvent.KIND) < rank(TranslationChapterEvent.KIND))
assertTrue(rank(ChapterEvent.KIND) < rank(TranslationChapterEvent.KIND))
assertTrue(rank(ChunkEvent.KIND) < rank(TranslationChunkEvent.KIND))
assertTrue(rank(TranslationChapterEvent.KIND) < rank(TranslationChunkEvent.KIND))
assertTrue(rank(TranslationChunkEvent.KIND) < rank(TranslationEvent.KIND))
assertTrue(rank(TranslationArtifactVersionEvent.KIND) < rank(TranslationEvent.KIND))
assertTrue(rank(DialectEvent.KIND) < rank(TranslationArtifactVersionEvent.KIND))
// A chapter and a translation artifact version both hang off an artifact
// *version*, which is not archived: it is derived from the signed
// artifact by the artifact's own arm in applyInnerEvent. So the artifact
// has to land before either of them, and the dependency runs through a
// kind that is not in this list at all.
assertTrue(rank(ArtifactEvent.KIND) < rank(ChapterEvent.KIND))
assertTrue(rank(ArtifactEvent.KIND) < rank(TranslationArtifactVersionEvent.KIND))
// And the numbers really do disagree with the order, which is why this is
// a list rather than a sortedBy { kind }.
@@ -256,22 +275,22 @@ class ArchiveEventTest {
@Test
fun `sorting a page puts what is referenced before what refers to it`() {
val jumbled = listOf(
payload(TranslationEvent.KIND),
payload(TranslationChapterEvent.KIND),
payload(ChunkEvent.KIND),
payload(DialectEvent.KIND),
payload(TranslationArtifactVersionEvent.KIND),
payload(ChapterEvent.KIND),
payload(ArtifactEvent.KIND),
payload(ArtifactVersionEvent.KIND),
)
assertEquals(
listOf(
DialectEvent.KIND,
ArtifactEvent.KIND,
ArtifactVersionEvent.KIND,
ChapterEvent.KIND,
ChunkEvent.KIND,
TranslationEvent.KIND,
TranslationArtifactVersionEvent.KIND,
TranslationChapterEvent.KIND,
),
ArchiveEvent.inApplyOrder(jumbled).map { it.kind }
)

351
composeApp/src/commonTest/kotlin/press/mantra/compose/nostr/archive/ArchiveRoundTripTest.kt Normal file
View File

@@ -0,0 +1,351 @@
package press.mantra.compose.nostr.archive
import com.vitorpamplona.quartz.nip01Core.core.Event
import com.vitorpamplona.quartz.nip01Core.core.hexToByteArray
import com.vitorpamplona.quartz.nip01Core.crypto.EventHasher
import com.vitorpamplona.quartz.nip01Core.signers.EventTemplate
import fr.acinq.bitcoin.ByteVector
import fr.acinq.bitcoin.ByteVector32
import fr.acinq.bitcoin.PrivateKey
import fr.acinq.bitcoin.crypto.frost.Frost
import fr.acinq.bitcoin.crypto.frost.IndividualNonce
import fr.acinq.bitcoin.crypto.frost.KeyMaterial
import fr.acinq.bitcoin.crypto.frost.SecretNonce
import fr.acinq.bitcoin.crypto.frost.Session
import fr.acinq.bitcoin.crypto.frost.TweakCache
import kotlin.test.Test
import kotlin.test.assertEquals
import kotlin.test.assertFalse
import kotlin.test.assertNotNull
import kotlin.test.assertTrue
import press.mantra.compose.database.model.MantraArtifact
import press.mantra.compose.database.model.MantraChapter
import press.mantra.compose.database.model.MantraChunk
import press.mantra.compose.database.model.MantraDialect
import press.mantra.compose.database.model.MantraTranslationArtifactVersion
import press.mantra.compose.database.model.MantraTranslationChapter
import press.mantra.compose.extensions.toHex
import press.mantra.compose.managers.SharedKeyDerivation
import press.mantra.compose.nostr.frost.GroupKeyStateEvent
import press.mantra.compose.nostr.nip30303.ArtifactEvent
import press.mantra.compose.nostr.nip30303.ChapterEvent
import press.mantra.compose.nostr.nip30303.ChunkEvent
import press.mantra.compose.nostr.nip30303.DialectEvent
import press.mantra.compose.nostr.nip30303.TranslationArtifactVersionEvent
import press.mantra.compose.nostr.nip30303.TranslationChapterEvent
/**
* The assumption the whole archive rests on: a row can be turned back into the
* event the group signed.
*
* Signed events are not stored as events. `FrostSigningManager.complete` applies
* them and what survives is a `Mantra*` row, so an archive has to rebuild each
* one with `toXEvent()` and hope it comes out byte-identical. If it does not,
* the id changes, the signature no longer covers it, and every receiver drops
* the payload as a forgery -- silently, one kind at a time.
*
* That is what the round-trip note on each `toXEvent` claims and what nothing
* asserted until now. Every kind in `ArchiveEvent.ARCHIVABLE_KINDS` is checked
* here against a real FROST quorum, because a signature that verifies is the
* only evidence that the rebuild is faithful -- comparing fields would only
* prove the test and the code agree about which fields matter.
*
* A kind that fails here cannot be archived at all, whatever the allowlist says.
*/
class ArchiveRoundTripTest {
private val participants = 3
private val threshold = 2
/** Stands in for a completed ceremony; nothing here is about the DKG. */
private val keyMaterial: KeyMaterial = Frost.trustedDealerKeygen(
thresholdSecretKey = PrivateKey(
ByteVector32("1c0ffee0000000000000000000000000000000000000000000000000000000a1")
),
nParticipants = participants,
threshold = threshold
)
private val room: SharedKeyDerivation.Derived = SharedKeyDerivation.derive(
thresholdPublicKey = keyMaterial.thresholdPublicKey.value.toHex(),
path = SharedKeyDerivation.MARMOT_ADMIN_GROUP_PATH
)
private val tweakCache: TweakCache = room.cache
/** The group's identity, which is also the room's id. */
private val chatRoomId = room.hex
private val dialectId = "b".repeat(64)
private val artifactVersionId = "c".repeat(64)
private val chapterId = "d".repeat(64)
private val translationArtifactVersionId = "e".repeat(64)
/** Exactly what `FrostSigningManager.unsignedEventOf` does. */
private fun unsignedEventOf(template: EventTemplate<*>) = Event(
id = EventHasher.hashId(
pubKey = chatRoomId,
createdAt = template.createdAt,
kind = template.kind,
tags = template.tags,
content = template.content
),
pubKey = chatRoomId,
createdAt = template.createdAt,
kind = template.kind,
tags = template.tags,
content = template.content,
sig = ""
)
/** A real quorum signing [eventId], in the manager's order. */
private fun groupSignature(eventId: String): String {
val message = ByteVector(eventId.hexToByteArray())
val signerIds = listOf(0, 1)
val nonces = signerIds.map { signerId ->
SecretNonce.generate(
sessionRandom = ByteVector32("a".repeat(63) + "${signerId + 1}"),
secretShare = keyMaterial.secretShares[signerId],
publicShare = keyMaterial.publicShares[signerId],
tweakedThresholdPublicKey = tweakCache.tweakedPublicKey,
message = message,
extraInput = null
)
}
val signingSession = Session.create(
aggregatedNonce = IndividualNonce.aggregate(nonces.map { it.second }).right!!,
signerIds = signerIds.map { it.toUInt() },
signerPublicShares = signerIds.map { keyMaterial.publicShares[it] },
nParticipants = participants,
threshold = threshold,
tweakCache = tweakCache,
message = message
)
val partials = signerIds.mapIndexed { position, signerId ->
signingSession.sign(
nonces[position].first,
keyMaterial.secretShares[signerId],
signerId.toUInt()
).right!!
}
return signingSession.aggregateSigs(partials).right!!.toByteArray().toHex()
}
/** A template, signed by the group, the way a finished session leaves one. */
private fun signed(template: EventTemplate<*>): Event {
val unsigned = unsignedEventOf(template)
return Event(
id = unsigned.id,
pubKey = unsigned.pubKey,
createdAt = unsigned.createdAt,
kind = unsigned.kind,
tags = unsigned.tags,
content = unsigned.content,
sig = groupSignature(unsigned.id)
)
}
/**
* The claim, for one kind: sign it, file it as a row, rebuild it from the
* row, and the group's signature still covers what comes out.
*/
private fun assertRoundTrips(template: EventTemplate<*>, rebuild: (Event) -> Event?) {
val signedEvent = signed(template)
assertTrue(
GroupKeyStateEvent.isSignedByRoom(signedEvent, chatRoomId),
"the harness itself must produce a verifiable event"
)
val rebuilt = assertNotNull(
rebuild(signedEvent),
"kind ${template.kind} did not survive being turned into a row"
)
// Asserted before the signature so a failure says which half broke: an id
// that moved means the tag order or a field changed in the rebuild, where
// a signature that fails on a matching id would mean something stranger.
assertEquals(
signedEvent.id,
rebuilt.id,
"kind ${template.kind} came back with a different id"
)
assertEquals(
signedEvent.sig,
rebuilt.sig,
"kind ${template.kind} lost the group's signature"
)
assertTrue(
GroupKeyStateEvent.isSignedByRoom(rebuilt, chatRoomId),
"kind ${template.kind} rebuilt into something the group's signature does not cover"
)
}
@Test
fun `a dialect survives the trip through a row`() {
assertRoundTrips(
DialectEvent.build(
name = "isiZulu",
country = "ZA",
language = "zu",
createdAt = 1_700_000_000L
)
) { event ->
MantraDialect.fromDialectEvent(
DialectEvent(event.id, event.pubKey, event.createdAt, event.tags, event.content, event.sig),
chatRoomId
)?.toDialectEvent()
}
}
@Test
fun `an artifact survives the trip through a row`() {
// The one that did not, when this test was written. Two faults, and the
// second is the interesting one: `toArtifactEvent` put the alt tag last
// where `build` puts it first, and it left out the version metadata
// entirely -- because that tag is not on the row at all. It is consumed
// into the artifact's first MantraArtifactVersion and dropped. So the
// label has to come back from there, which is why it is a parameter.
assertRoundTrips(
ArtifactEvent.build(
name = "In Detention",
url = "https://example.com/in-detention",
visibility = "private",
license = "cc",
dialectId = dialectId,
versionLabel = "1.0",
createdAt = 1_700_000_000L
)
) { event ->
MantraArtifact.fromArtifactEvent(
ArtifactEvent(event.id, event.pubKey, event.createdAt, event.tags, event.content, event.sig),
chatRoomId
)?.toArtifactEvent(versionLabel = "1.0")
}
}
@Test
fun `an artifact rebuilt with the wrong version label is not the one that was signed`() {
// What the parameter costs if a caller guesses. The label was part of
// what the group put its signature to, so a rebuild carrying a different
// one is a different event -- and it fails as a forgery rather than as a
// mistake, which is why the assembler reads it off the initial version
// rather than defaulting it.
val signedEvent = signed(
ArtifactEvent.build(
name = "In Detention",
url = "https://example.com/in-detention",
visibility = "private",
license = "cc",
dialectId = dialectId,
versionLabel = "1.0",
createdAt = 1_700_000_000L
)
)
val rebuilt = MantraArtifact.fromArtifactEvent(
ArtifactEvent(
signedEvent.id, signedEvent.pubKey, signedEvent.createdAt,
signedEvent.tags, signedEvent.content, signedEvent.sig
),
chatRoomId
)?.toArtifactEvent(versionLabel = "2.0")
assertNotNull(rebuilt)
assertFalse(GroupKeyStateEvent.isSignedByRoom(rebuilt, chatRoomId))
}
@Test
fun `a chapter survives the trip through a row`() {
assertRoundTrips(
ChapterEvent.build(
artifactVersionId = artifactVersionId,
name = "Chapter One",
originalText = "He was a man of parts.",
index = 0,
wordCount = 6,
characterCount = 22,
createdAt = 1_700_000_000L
)
) { event ->
MantraChapter.fromChapterEvent(
ChapterEvent(event.id, event.pubKey, event.createdAt, event.tags, event.content, event.sig),
chatRoomId
)?.toChapterEvent()
}
}
@Test
fun `a chunk survives the trip through a row`() {
assertRoundTrips(
ChunkEvent.build(
chapterId = chapterId,
text = "He was a man of parts.",
index = 0,
wordCount = 6,
characterCount = 22,
createdAt = 1_700_000_000L
)
) { event ->
MantraChunk.fromChunkEvent(
ChunkEvent(event.id, event.pubKey, event.createdAt, event.tags, event.content, event.sig),
chatRoomId
)?.toChunkEvent()
}
}
@Test
fun `a translation artifact version survives the trip through a row`() {
assertRoundTrips(
TranslationArtifactVersionEvent.build(
artifactVersionId = artifactVersionId,
dialectId = dialectId,
name = "isiZulu",
visibility = "private",
license = "cc",
createdAt = 1_700_000_000L
)
) { event ->
MantraTranslationArtifactVersion.fromTranslationArtifactVersionEvent(
TranslationArtifactVersionEvent(
event.id, event.pubKey, event.createdAt, event.tags, event.content, event.sig
),
chatRoomId
)?.toTranslationArtifactVersionEvent()
}
}
@Test
fun `a translation chapter survives the trip through a row`() {
assertRoundTrips(
TranslationChapterEvent.build(
translationArtifactVersionId = translationArtifactVersionId,
chapterId = chapterId,
index = 0,
createdAt = 1_700_000_000L
)
) { event ->
MantraTranslationChapter.fromTranslationChapterEvent(
TranslationChapterEvent(
event.id, event.pubKey, event.createdAt, event.tags, event.content, event.sig
),
chatRoomId
)?.toTranslationChapterEvent()
}
}
@Test
fun `every archivable kind has a round-trip test above`() {
// The list and this file have to move together. A kind added to the
// allowlist without a case here is one nobody has checked can be rebuilt,
// and the failure is silent: the receiver drops it as a forgery.
assertEquals(
6,
ArchiveEvent.ARCHIVABLE_KINDS.size,
"an archivable kind was added or removed; add or remove its round-trip case"
)
}
}