Commit Graph

10 Commits

Author SHA1 Message Date
Kgothatso Ngako
bf4041a5b2 feat: mantra compiles for the jvm
Phase 4. Declares jvm(), implements all 16 expects, and bumps the
submodule to the fork branch carrying phases 1-3.
:composeApp:compileKotlinJvm is green.

**The actuals were the small half. Room was the blocker.** The first jvm
compile failed with 58 copies of "Only suspend functions are allowed in
DAOs declared in source sets targeting non-Android platforms". Room
permits blocking query methods on android and nowhere else, so every @Dao
function that was neither suspend nor Flow-returning had to change --
58 of them across 24 files. KSP reports these in alphabetical batches, so
the count shrinks in stages and looks bottomless; scanning the dao package
directly for abstract funs with no suspend and no Flow return finds them
all at once.

It stops there, which is the only reason this is a 58-line change rather
than a refactor. Every one of the 15 call sites outside the dao package
was already inside a suspend function -- the repositories were written
that way throughout -- so nothing needed rewriting. One private helper,
DatabaseNostrRepository.matchNegentropicNostrEvents, had to become
suspend, and its single caller was already suspend, so the cascade
terminated immediately. Zero call-site edits.

**The cost lands on android, not on the jvm.** A blocking DAO method runs
on its caller's thread; a suspend one is dispatched to the query coroutine
context, which getRoomDatabase sets to Dispatchers.IO. That is the better
behaviour -- it is what stops a query running on the main thread -- but it
is a real change to the shipping platform, made for a target that does not
run yet. Hence the unit tests below rather than a compile alone.

**BusinessManager was not an expect**, so nothing warned about it. It is
now ported to the fork's jvmMain (05ce7eb); Phoenix.jvm.kt and
NavigationViewModel.jvm.kt are otherwise the ios actuals with one changed
import, since those files use no ios API.

**schedulePlatformLogic schedules nothing, and logs that it does not.**
Android starts two WorkManager jobs here, one of which is ChannelsWatcher
-- it wakes periodically to notice a channel force-closed while the app
was shut. A desktop application has no process once its window closes, so
there is nothing to wake, and running the watcher in-process would be
strictly worse than not running it: it would only fire while the app was
already open and watching. The exposure is real and belongs in release
notes rather than a comment -- a desktop wallet left closed past a
force-close deadline does not notice.

Smaller calls. PlatformContext carries an application directory, since
there is no Context to read one from, and PlatformDatabaseBuilder puts
aux.db under it rather than in java.io.tmpdir, which is what the abandoned
Aux implementation did behind a TODO and which most systems clear on
reboot. themeColorScheme ignores dynamicColor, which means Material You
and has no desktop counterpart. AppVersion reads the jar manifest that
compose.desktop writes, falling back when running from a class directory.

Verified: :composeApp:compileKotlinJvm green,
:composeApp:compileDebugKotlinAndroid green, and
:composeApp:testDebugUnitTest 52 passing -- the one that matters, since
this commit changes shared code every android query path goes through.

Not verified: nothing has run. No jvm entry point exists yet, so the
database has never been opened on this platform and no business has been
started. That is phase 5, which also has to unlock JvmKeyStore before the
wallet starts -- a passphrase prompt, not just a window.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-09-06 01:23:42 +02:00
Kgothatso Ngako
670f87a609 docs: record what phase 3 turned out to require
Phase 3 is implemented in the fork on claude/jvm-target-actuals (ce49657).
The security analysis in the plan held up; three practical constraints
around it did not appear until the code was written.

**A passphrase-derived KEK is not a drop-in.** The plan treated the choice
between a passphrase, an OS keychain and a key file as the whole decision.
But keyStoreEncryption(keyName, plainText) takes no context and no secret
-- on android the OS holds the key, so none is needed -- which means any
passphrase scheme needs an out-of-band unlock the expect cannot express.
That is a change to application startup, not just to the actual, so it is
now called out against phase 5: the desktop entry point has to prompt and
unlock before the wallet starts.

**The iv must be 16 bytes.** EncryptedSeed.V2.serialize in commonMain
throws on anything else, which rules out a conventional 96-bit GCM nonce
-- worth knowing before designing around one. It turns out to help: with
randomly generated nonces the risk is a repeat under one key, and 128 bits
makes that vanishingly unlikely where 96 merely makes it unlikely.

**Argon2id costs a dependency.** The jdk has PBKDF2 and no memory-hard
KDF at all, so it means bouncycastle. Recorded with the reason to pay it:
if the build is dev-only because it lacks hardware backing, weakening the
KDF too gets the trade backwards.

Also recorded: wrap a per-name data key under the KEK rather than
encrypting the seed with it directly, so a passphrase change rewraps 32
bytes; throw java.security.KeyStoreException when locked, since the
graceful* wrappers already map it to
DecryptSeedResult.Failure.KeyStoreFailure; and a verification section
naming the properties that fail quietly, plus the two limits worth writing
down rather than fixing -- the first unlock on a new store accepts any
passphrase, and zeroing the key is best effort.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-09-06 01:13:07 +02:00
Kgothatso Ngako
506dfea802 docs: correct phase 2 against what the jdbc drivers actually needed
Phase 2 is implemented and verified in the fork on
claude/jvm-target-actuals (d1a82ea). Three corrections and one omission.

**Schema handling does not need hand-rolling.** The plan said "you call
Schema.create(driver) and the migration path explicitly, and you have to
track the applied version yourself". SQLDelight 2.x ships a factory
function that shadows the constructor -- JdbcSqliteDriver(url, properties,
schema, migrateEmptySchema, vararg callbacks) -- which does all three,
user_version included. The same-named constructor does none of it, which
is the trap worth naming rather than the work that was budgeted for.

**Foreign keys were the actual work, and the plan never mentioned them.**
Off by default in SQLite, and the pragma is per connection while
JdbcSqliteDriver opens one per thread, so it has to go through the
connection Properties rather than be issued once against the driver.
Recorded along with why that needs no compile dependency on
org.xerial:sqlite-jdbc, which arrives at runtime scope only.

**commonTest has an expect too.** The 23 counted at the top of this
document are commonMain's. Declaring jvm() also creates jvmTest, which
inherits commonTest, so `connect` in ElectrumServersTest blocks every jvm
test from compiling. Noted along with the reason not to stub it empty the
way ios does: the class is @Ignore'd everywhere, so an empty body looks
harmless right up until somebody removes the @Ignore and
connect_to_mainnet_servers starts passing without connecting to anything.

**Phase 2 is the first phase that can be run, and the plan told you not to
bother.** It said "none of this is exercisable until Phase 4. Write the
SQLDelight schema-creation path against a scratch main() if you want
feedback sooner." That was wrong twice: library/src/jvmTest/ already
exists, and the two properties worth checking are exactly the ones a
compiler cannot see. Schema creation and the foreign-key pragma both fail
silently in production -- a missing table only shows up at first query,
and foreign keys being off means cascading deletes quietly do not happen.
The phase now carries a real exit condition, and DbFactoryJvmTest meets it
with five passing tests.

Recorded with it: the two KeyStoreFunctions actuals have to exist before
phase 3 decides anything, because nothing jvm compiles without them, and
they should throw rather than do something plausible.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-09-06 01:04:02 +02:00
Kgothatso Ngako
0757e50dc5 docs: correct the jvm plan against what phase 1 actually did
Phase 1 is implemented and verified in the lightning-kmp-app fork on
claude/jvm-target-actuals (27a0054). Four things in the plan were wrong,
and doing the work is what surfaced them.

**jvm() belongs at the start of phase 1, not phase 4 -- for the library.**
The plan said leave it off in both builds until phase 4. That is right for
mantra and wrong for the fork: library/src/jvmMain/ is an orphan source
set until the library declares the target, so phases 1-3 would all have
been written blind. Declared first, `:library:compileKotlinJvm` names the
remaining expects, and that list beats grepping for `expect ` -- it
shrinks by exactly what you implement and cannot drift from the truth. The
build stays red across phases 1-3 by design.

That checklist is now recorded as the phase 1 exit condition: exactly
eight expects should remain, and exactly which eight. Anything else means
something in the phase is wrong.

**Phase 3 is two decisions, not four.** gracefulSingleSeedDecryption and
gracefulMultiSeedDecryption are pure exception mapping into a
DecryptSeedResult, and the exception they branch on is
java.security.KeyStoreException -- a plain JCA type that exists on the jvm.
Both are near-copies of the android actuals and need nothing settled
first, so they move alongside phase 2. Only keyStoreEncryption and
keyStoreDecryption are the security decision, and that part of the
analysis stands.

**The Fibonacci template must not be deleted.** The plan said to drop it
"assuming nothing references them". Things do: generateFibi is exercised
by template tests in commonTest, androidHostTest, iosTest, jvmTest and
linuxX64Test, and JvmFibiTest asserts a value that depends on precisely
the two properties fibiprops.jvm.kt defines. That file already satisfies
two of the 25 expects, which is why the count was 23 missing rather than
25. Removing the template is five test files plus four fibiprops.*
actuals, and it is a separate cleanup.

**Phase 1 is fifteen actuals, not fourteen**, and two of them are not
copies of android -- platformElectrumRegtestConf (10.0.2.2 is the
emulator's alias for the host loopback; a jvm process is already on the
host) and phoenixLogWriters (android routes kermit into slf4j because
android tooling reads that back).

Also recorded, because it cost time: a worktree cannot run gradle at all
until the submodules are checked out *and* local.properties exists at five
levels. Neither is version controlled, so a fresh worktree has neither,
and the failure surfaces four builds down at
:...:secp256k1-kmp:jni:android as "SDK location not found" rather than
anywhere obviously related.

Both builds were run: `:library:compileKotlinJvm` fails only on the known
eight, and `:composeApp:compileDebugKotlinAndroid` still passes with the
library's jvm target declared -- the check that matters, since a new
variant must not change how the android target resolves the library.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-09-06 00:53:51 +02:00
Kgothatso Ngako
2aaa7b99a6 build: phase 0 of the jvm target -- clear the ground, correct the plan
First phase of docs/jvm-target.md. Nothing here turns the target on; it
removes what would break the moment it is turned on, and stages the two
catalog entries that cannot be derived automatically. Two of the four
steps as written in the doc turned out to be wrong, and implementing them
is how that surfaced -- both are corrected in the doc in this commit.

**Deleted the stale jvmMain tree.** Six files under
composeApp/src/jvmMain/kotlin/ac/cord/auxiliary/ survived from the Aux
project this codebase grew out of. They have gone unnoticed because
`jvmMain` is currently an orphan source set -- the accessor creates it,
no target compiles it -- so the wrong package, the Room 2 imports
(androidx.room, not androidx.room3), and the references to a long-gone
AuxDatabase and AuxGlobal have never had to resolve. They would all become
compile errors in phase 4.

They are not lost: they are the closest thing to a skeleton for five of
the six platform actuals phase 4 needs, and main.kt is a reasonable
starting shape for the phase 5 desktop entry point. `git show HEAD~1` has
them.

**Added two catalog entries, not four.** sqlite-bundled-jvm and
sqldelight-sqlite-driver. Both earn their place by being unreachable
otherwise: sqlite-bundled-jvm has to be named explicitly because
variant-aware resolution hands the *android* artifact to anything running
on the host, and sqldelight-sqlite-driver is the jvm counterpart to the
android-driver and native-driver entries already there.

The doc also listed room3-runtime-jvm and sqldelight-jdbc-driver. Neither
is right. Once jvm() exists, commonMain's existing androidx-room3-runtime
resolves to the -jvm variant on its own, so an explicit entry is
redundant and would drift. And the SQLDelight drivers phase 2 needs are
for DbFactory, which lives in lightning-kmp-app -- a separate gradle build
with its own version catalog, where an entry here is simply not visible.

**kspJvm cannot be wired yet, and the build file already said so.** The
doc's phase 0 told you to uncomment
composeApp/build.gradle.kts:194. It contradicted its own phase 4, which is
where jvm() gets turned on. The comment three lines above it states the
rule:

    These configurations only exist when the ios targets are declared,
    which the kotlin block above does only on a mac.

The same holds for kspJvm -- `dependencies { add("kspJvm", ...) }` throws
UnknownConfigurationException until a jvm() target creates the
configuration. So it moves into phase 4, into the same edit that declares
the target. composeApp/build.gradle.kts is deliberately untouched by this
commit.

**Also documented: gradle does not run in a worktree here at all** until
the submodule is checked out, which worktrees do not do automatically.
`lightning-kmp-app/` is empty and configuration fails with "Project with
path ':library' not found in build ':lightning-kmp-app'". Recorded in the
phase 0 verification section along with the caveat that a linked worktree
shares .git/modules/ with the main checkout, so both trees end up on one
submodule git dir.

**Not verified by a build.** For that reason. The deletion is an orphan
source set and the additions are unreferenced catalog lines, so neither
can change a build's outcome -- but that is an argument, not a green
check, and it is the second commit in a row on this branch that has not
compiled anything. Phase 4 is the first phase that genuinely cannot be
done without a working gradle invocation.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-09-06 00:44:10 +02:00
Kgothatso Ngako
5abc37e463 docs: scope the jvm target, and separate it from testing the daos
Two questions arrived together -- whether Room's own testing guidance
applies to this project, and what desktop support would cost -- and they
turned out to have opposite answers. Both are now in docs/jvm-target.md,
phased, with the blocking work separated from the mechanical work.

**The expensive part is already done.** The four-deep native chain --
secp256k1 -> bitcoin-kmp -> lightning-kmp -> lightning-kmp-app -- already
builds for JVM, on every android build we do. The comment at
composeApp/build.gradle.kts:50 records the mechanism without drawing the
conclusion: lightning-kmp-core publishes no android variant, so our
android target resolves it to the *jvm* one, which pulls
secp256k1-kmp-jni-jvm desktop natives, which is exactly why the build has
to name the android artifact by hand. Read the other way round, every JVM
artifact in the chain is already compiled from source by the composite
build. A jvm target adds no cinterop, no C compilation and no new native
constraints. That was the part worth being afraid of, and it is finished.

**The blocker is one level down, and smaller than it looks.**
lightning-kmp-app/library declares 25 expects and implements them across
35 androidMain files. Its jvmMain holds exactly one: fibiprops.jvm.kt, the
Kotlin multiplatform library template's Fibonacci boilerplate, satisfying
two of the 25 -- both of them the template's own. So 23 actuals are
missing, which is why jvm() is commented out there
(library/build.gradle.kts:18), which is why it is commented out here
(composeApp/build.gradle.kts:46). Mantra cannot declare the target until
the fork does.

Six phases, ordered by that dependency. 0 build config; 1 the fourteen
mechanical phoenix actuals; 2 the three SQLDelight JDBC drivers and
NetworkMonitor; 3 key storage; 4 mantra's own sixteen expects; 5 the
desktop entry point. 1-3 are independent and parallelisable, 4 is where
the compiler finally checks the whole thing. Roughly a week to a
launchable build.

**Phase 3 has no day estimate, deliberately.** keyStoreEncryption /
keyStoreDecryption and their two graceful* wrappers delegate on android to
KeystoreHelper.kt -- 116 lines against AndroidKeyStore, StrongBox
attempted first and fallen back from, key material never leaving hardware.
Desktop JVM has no equivalent, so this is a decision rather than a port,
and the doc gives the three real options against what each actually
protects. A fixed-key JCEKS file is named there as a liability rather than
a stopgap: this is wallet seed material, and it lands on top of the
plaintext-key finding already open against this codebase. Recommended
sequencing is a passphrase-derived KEK with the desktop build marked
unsuitable for real funds, so phases 4 and 5 can proceed without the
security question being quietly treated as answered.

Two inherited mistakes are called out rather than carried forward. The old
Aux jvmMain put the database in java.io.tmpdir behind a TODO -- the doc
says not to inherit that in either phase that touches it. And
schedulePlatformLogic goes through WorkManager on android with no desktop
counterpart, so the doc asks for an explicit choice between a no-op and an
in-process coroutine, written down.

**The DAO answer is an appendix, because it is the opposite answer.** None
of the above is needed to test the DAOs, and burying that would have been
misleading. room3-runtime-android:3.0.1 already exposes the no-Context
inMemoryDatabaseBuilder(Function0<T>) overload, and
MantraDatabaseConstructor already supplies what it needs, so Room's
recommended host-machine form compiles in commonTest and runs under
testDebugUnitTest today. The one trap is native and is the secp256k1
problem mirrored: sqlite-bundled-android ships only android-ABI .so under
jni/, so a local unit test's JVM cannot load it and BundledSQLiteDriver
fails at construction; sqlite-bundled-jvm on the androidUnitTest classpath
is the fix. Robolectric neither helps nor is needed -- it cannot load
android .so on the host either.

Everything structural here was checked against the artifacts rather than
recalled: the Room builder overloads by javap on room3-runtime-android,
the two sqlite-bundled native layouts by unzipping both, and the
availability of room3-runtime-jvm, room3-testing, quartz-jvm and the two
SQLDelight drivers by request against the repositories this build actually
resolves from. The absence of android.* and java.* imports in commonMain,
and of any NFC reference from it, was likewise grepped rather than
assumed.

**Not verified: anything that requires compiling.** No jvm target was
turned on, nothing was built, and the day estimates are estimates. Phase 4
is where dependency-substitution surprises would surface if there are any,
and it is precisely the phase nothing here exercises.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-09-06 00:38:11 +02:00
Kgothatso Ngako
d110737f9a fix: keep a room's MlsGroup alive so a late message can still be read
Two events published in the same second reliably lose one of them. The
receiver stores the kind:445 and produces nothing from it -- no inner
event, no chat line, no error anybody sees, because MarmotGroupEvent is
written before the message is decrypted and so survives while everything
downstream silently does not.

Observed as a FROST signing session that never started on the receiver:
proposeSigning publishes the proposal and then the proposer's own nonce,
the relay handed them back in the other order, and the proposal was
dropped. The nonce is still sitting there filed against a session that
will never exist. The same bug ate a dialect earlier, which then took out
the artifact referencing it via a foreign key.

MLS is specified to tolerate this. RFC 9420 says a receiver that gets
generation N+1 before N keeps the intermediate keys so the older message
can still be read, and quartz's SecretTree does exactly that, in a
private skippedKeys map. What it does not do is persist it:
exportSenderStates() returns the ratchet positions only, so saveState()
drops the cache. NostrDao rebuilt the group from stored state for every
inbound event, so the cache was empty every single time, and generation N
arriving after N+1 failed `require(generation >= applicationGeneration)`
and was swallowed. Terminal -- the key is derived from a ratchet that has
moved past it, and nothing asks the sender to resend.

This keeps the instance alive instead. MlsGroupCache holds one MlsGroup
per room, and the inbound path goes through it, so skippedKeys survives
from one message to the next. That covers the case that actually bites --
a burst arriving in one sync, decrypted one after another against the
same tree -- which is what every bursty flow needs: proposeRitual sends
two, addArtifact sends two, and addChapter sends one per paragraph plus
one, of which only the ones arriving in ascending generation order
survived.

Reuse is conditional on the stored state still being exactly what the
cache last wrote. Sending a message advances the sender ratchet and saves;
so does adding a member. When that happens the cache rebuilds rather than
carrying on from a group that has been overtaken -- which is what keeps
this from being worse than no cache at all: the fallback is always the old
behaviour, never a diverged ratchet.

One lock per room, not one overall, because the group is mutable and
decryption advances it: two events for the same room decrypted at once
would corrupt the tree, and a busy room should not hold up a quiet one.

**This is a mitigation, not the fix.** It does not survive a restart, and
it does not survive another writer, so a long enough reorder still loses
the message. The fix belongs in quartz -- carry skippedKeys through
saveState/restore -- and quartz is a mavenCentral binary, not a fork, so
it cannot be made here. docs/mls-skipped-keys.md has the analysis, the
patch, the migration constraint on the persisted state format, and the
three ways to actually land it.

Not verified end to end: the proposal that exposed this cannot be
recovered, since its generation is already past, so confirming the fix
needs a fresh burst.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-09-05 23:09:53 +02:00
Kgothatso Ngako
3dea07135c fix: add a group's whole membership in one commit, closing the epoch race
`MarmotOutboundDao.addMembersToChatRoom` stages every member with `proposeAdd` and
issues a single `commit()`. Both callers that know their membership up front now
use it: `SelectChatRoomTypeViewModel.inviteMembers` at room creation, and
`DkgRitualViewModel.inviteAdmins` for the #admins room.

Inviting one at a time created an epoch per member, and each of those commits
raced the previous member's welcome. MarmotInboundManager refuses future-epoch
messages outright, on both wire formats, with no queue and no replay -- so the
member who lost that race was silently stuck an epoch behind while the caller saw
a successful invite. Deriving isOneMemberInitialGroupCreation narrowed that window;
this removes it. No member ever has to process a commit for an epoch they were not
yet in, so there is no longer a race to lose.

One commit yields one welcome: `buildWelcome` emits an EncryptedGroupSecrets per
added member and each joiner finds its own entry by key package reference. The blob
is shared, delivery stays per peer, because each welcome event is tagged with that
peer's key package.

## Why this needed no schema change

Batching at creation time means the single commit happens while the group is still
only its creator, which takes the immediate-welcome branch: nothing is broadcast
and MarmotCommitResult is never written. The bookkeeping that assumes one peer per
commit is simply not on this path.

So the batch is taken only when `members().size == 1`, and anything else falls back
to inviting sequentially -- correct, if not ideal. Batching into an established
group would take the deferred branch, where `peerKeyPackageEventId` is singular and
the ack-triggered delivery in DatabaseNostrRepository expects one welcome; making
that work needs a list there and a fan-out on acknowledgement. Nothing currently
adds several members to an established group, so that is left outstanding and
documented rather than speculatively built.

The group state is persisted after `commit()` and before any welcome goes out, so a
crash between them leaves the group at the epoch the welcomes describe rather than
one behind it.

## Reporting

Members with no published key package still cannot be added -- a Marmot invite
needs one -- and are now returned alongside any that failed to receive their
welcome, rather than the two being conflated. Both still only reach the log; the
coordinator is not yet told.

docs/marmot-membership.md is updated in the same change: batching moves from
outstanding work to described behaviour, with the schema constraint that shapes it
and the remaining fan-out work recorded. The note about sequential invites is
narrowed to where they still happen.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-09-05 15:02:06 +02:00
Kgothatso Ngako
8fc1c9e650 fix: stop deferring the first invitee's welcome behind a commit nobody needs
`inviteMember` now works out for itself whether the group it is adding to has
anybody to inform:

    val isOneMemberInitialGroupCreation = mlsGroup.members().size == 1

read before `addMember` advances the tree. The parameter is gone from the
signature and no caller passes it any more.

Callers were the wrong place for this decision and both of them got it wrong.
`inviteMemberToChatRoom` hardcoded `false`, and `ChatRepository.inviteMember` did
not expose it at all, so every invite made through a group -- room creation in
SelectChatRoomTypeViewModel, and the #admins room -- took the deferred-welcome
path. That includes the first invite, when the group is still only its creator, at
which point:

  - the commit has no audience. No other member exists, and nobody outside the
    group can decrypt it, so it is noise on the relay.
  - the welcome is then withheld until a relay acknowledges that noise. If the ack
    never lands, the first invitee receives nothing at all.

Only createMlsDirectMessageChatRoom passed `true`, and only because a DM has
exactly one invite. A group of n has one such invite too -- the first -- and it was
not getting it.

The condition is right at any size, not just for DMs: "the group has nobody to
inform" is true exactly once. Invite two sees one member who must advance, invite
three sees two, and so on. Their commits are encrypted with
`commitResult.preCommitExporterSecret`, the epoch the earlier invitees received in
their own welcome, so they can decrypt and advance. `members()` skips empty leaves,
so this also stays correct for a group that has had members removed.

## What this does and does not fix

It removes a pointless commit and, with DefaultDMRelayList now a single relay, a
single point of failure sitting in front of every group's first member.

It also narrows a silent race rather than closing it. MarmotInboundManager refuses
future-epoch messages outright on both wire formats -- no queue, no replay -- so a
commit arriving before its recipient's welcome is dropped and that member never
advances, while the coordinator sees a successful invite. Previously both commits
went out before either welcome; now welcome 1 is sent before commit 2 exists, so
the first invitee is already at the right epoch. For n >= 3 the window between
welcome 1 and commit 2 remains.

Closing it needs the adds batched into one commit, which is the outstanding work
described in docs/marmot-membership.md. That doc is updated here to describe the
derived flag as current behaviour rather than a proposal, and to keep batching as
the remaining item.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-09-05 14:44:28 +02:00
Kgothatso Ngako
b99cb8fcd5 docs: write down the shared-key subsystem and how Marmot membership fails
First docs in the repo -- README.md is still the stock KMP template. Three
documents plus an index, covering the parts whose behaviour is not recoverable by
reading the code: where the reasoning lives in a protocol, where a failure mode is
silent, or where a decision looked arbitrary and was not.

marmot-membership.md is the one that earns its place. Everything about adding a
member compiles, the invite reports success, and a member simply never appears --
and the reason is never in the invite code. It records that
inviteMemberToChatRoom hardcodes isOneMemberInitialGroupCreation = false and that
ChatRepository does not expose it, so every group invite takes the deferred-welcome
path including the first, when the group is still just its creator and the commit
has no audience at all. Then why that is silent rather than noisy:
MarmotInboundManager refuses future-epoch messages outright, on both wire formats,
with no queue and no replay, so a commit arriving before its recipient's welcome
is dropped and that member never advances. EPOCH_RETENTION_WINDOW retains past
epochs and does nothing for messages from ahead. Three options are set out with the
per-invite correctness table, including the honest limit that the recommended one
narrows the race without closing it.

shared-key-derivation.md argues why the paths are not BIP32 -- no chain code
exists, hardened derivation is impossible rather than unimplemented, and a FROST
tweak takes the scalar as input so the chain code leaves the problem entirely. It
records the x-only serialisation trap avoided by choosing the scalar directly, and
states the rule that must not be broken: never reconstruct a derived key in the
clear, because k = k' - t hands over the group key rather than one derived key.

shared-key-ceremony.md covers the seven kinds, the three approval gates and why
the coordinator's aggregations are deliberately not among them, faults as values
rather than exceptions, and the transcript's idempotency-by-construction. It also
writes down the invariant that produces no error when broken: pendingApproval must
mirror the gates in advance, or the screen offers an approval that does nothing --
or none while the ritual sits still.

Every factual claim was checked against the source rather than recalled, which
turned up one correction worth having: there are two future-epoch refusals, for
PrivateMessage and for Commit, so the drop covers both wire formats and not just
one.

Each document leads with the failure mode rather than the architecture, on the
grounds that a failure is what sends somebody to docs in the first place, and each
lists its known gaps -- including that none of this has run on a physical device.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-09-05 14:39:19 +02:00