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automerge/javascript/test/sync_test.ts
Alex Good 1e7dcdedec automerge-js: Add prettier 
It's christmas, everyone is on holiday, it's time to change every single
file in the repository!
2022-12-22 17:33:14 +00:00

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import * as assert from "assert"
import * as Automerge from "../src"
import { BloomFilter } from "./legacy/sync"
import {
decodeSyncMessage,
encodeSyncMessage,
decodeSyncState,
encodeSyncState,
initSyncState,
} from "../src"
function getHeads(doc) {
return Automerge.getHeads(doc)
}
function getMissingDeps(doc) {
return Automerge.getMissingDeps(doc, [])
}
function sync(
a,
b,
aSyncState = initSyncState(),
bSyncState = initSyncState()
) {
const MAX_ITER = 10
let aToBmsg: Automerge.SyncMessage | null = null,
bToAmsg: Automerge.SyncMessage | null = null,
i = 0
do {
;[aSyncState, aToBmsg] = Automerge.generateSyncMessage(a, aSyncState)
;[bSyncState, bToAmsg] = Automerge.generateSyncMessage(b, bSyncState)
if (aToBmsg) {
;[b, bSyncState] = Automerge.receiveSyncMessage(b, bSyncState, aToBmsg)
}
if (bToAmsg) {
;[a, aSyncState] = Automerge.receiveSyncMessage(a, aSyncState, bToAmsg)
}
if (i++ > MAX_ITER) {
throw new Error(
`Did not synchronize within ${MAX_ITER} iterations. Do you have a bug causing an infinite loop?`
)
}
} while (aToBmsg || bToAmsg)
return [a, b, aSyncState, bSyncState]
}
describe("Data sync protocol", () => {
describe("with docs already in sync", () => {
describe("an empty local doc", () => {
it("should send a sync message implying no local data", () => {
let n1 = Automerge.init()
let s1 = initSyncState()
let m1
;[s1, m1] = Automerge.generateSyncMessage(n1, s1)
const message = decodeSyncMessage(m1)
assert.deepStrictEqual(message.heads, [])
assert.deepStrictEqual(message.need, [])
assert.deepStrictEqual(message.have.length, 1)
assert.deepStrictEqual(message.have[0].lastSync, [])
assert.deepStrictEqual(message.have[0].bloom.byteLength, 0)
assert.deepStrictEqual(message.changes, [])
})
it("should not reply if we have no data as well", () => {
let n1 = Automerge.init(),
n2 = Automerge.init()
let s1 = initSyncState(),
s2 = initSyncState()
let m1: Automerge.SyncMessage | null = null,
m2: Automerge.SyncMessage | null = null
;[s1, m1] = Automerge.generateSyncMessage(n1, s1)
if (m1 != null) {
;[n2, s2] = Automerge.receiveSyncMessage(n2, s2, m1)
}
;[s2, m2] = Automerge.generateSyncMessage(n2, s2)
assert.deepStrictEqual(m2, null)
})
})
describe("documents with data", () => {
it("repos with equal heads do not need a reply message", () => {
let n1 = Automerge.init<any>(),
n2 = Automerge.init<any>()
let s1 = initSyncState(),
s2 = initSyncState()
let m1: Automerge.SyncMessage | null = null,
m2: Automerge.SyncMessage | null = null
// make two nodes with the same changes
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.n = []))
for (let i = 0; i < 10; i++)
n1 = Automerge.change(n1, { time: 0 }, doc => doc.n.push(i))
;[n2] = Automerge.applyChanges(n2, Automerge.getAllChanges(n1))
assert.deepStrictEqual(n1, n2)
// generate a naive sync message
;[s1, m1] = Automerge.generateSyncMessage(n1, s1)
assert.deepStrictEqual(s1.lastSentHeads, getHeads(n1))
// heads are equal so this message should be null
if (m1 != null) {
;[n2, s2] = Automerge.receiveSyncMessage(n2, s2, m1)
}
;[s2, m2] = Automerge.generateSyncMessage(n2, s2)
assert.strictEqual(m2, null)
})
it("n1 should offer all changes to n2 when starting from nothing", () => {
let n1 = Automerge.init<any>(),
n2 = Automerge.init<any>()
// make changes for n1 that n2 should request
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.n = []))
for (let i = 0; i < 10; i++)
n1 = Automerge.change(n1, { time: 0 }, doc => doc.n.push(i))
assert.notDeepStrictEqual(n1, n2)
const [after1, after2] = sync(n1, n2)
assert.deepStrictEqual(after1, after2)
})
it("should sync peers where one has commits the other does not", () => {
let n1 = Automerge.init<any>(),
n2 = Automerge.init<any>()
// make changes for n1 that n2 should request
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.n = []))
for (let i = 0; i < 10; i++)
n1 = Automerge.change(n1, { time: 0 }, doc => doc.n.push(i))
assert.notDeepStrictEqual(n1, n2)
;[n1, n2] = sync(n1, n2)
assert.deepStrictEqual(n1, n2)
})
it("should work with prior sync state", () => {
// create & synchronize two nodes
let n1 = Automerge.init<any>(),
n2 = Automerge.init<any>()
let s1 = initSyncState(),
s2 = initSyncState()
for (let i = 0; i < 5; i++)
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.x = i))
;[n1, n2, s1, s2] = sync(n1, n2)
// modify the first node further
for (let i = 5; i < 10; i++)
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.x = i))
assert.notDeepStrictEqual(n1, n2)
;[n1, n2, s1, s2] = sync(n1, n2, s1, s2)
assert.deepStrictEqual(n1, n2)
})
it("should not generate messages once synced", () => {
// create & synchronize two nodes
let n1 = Automerge.init<any>("abc123"),
n2 = Automerge.init<any>("def456")
let s1 = initSyncState(),
s2 = initSyncState()
let message
for (let i = 0; i < 5; i++)
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.x = i))
for (let i = 0; i < 5; i++)
n2 = Automerge.change(n2, { time: 0 }, doc => (doc.y = i))
// n1 reports what it has
;[s1, message] = Automerge.generateSyncMessage(n1, s1)
// n2 receives that message and sends changes along with what it has
;[n2, s2] = Automerge.receiveSyncMessage(n2, s2, message)
;[s2, message] = Automerge.generateSyncMessage(n2, s2)
assert.deepStrictEqual(decodeSyncMessage(message).changes.length, 5)
//assert.deepStrictEqual(patch, null) // no changes arrived
// n1 receives the changes and replies with the changes it now knows n2 needs
;[n1, s1] = Automerge.receiveSyncMessage(n1, s1, message)
;[s1, message] = Automerge.generateSyncMessage(n1, s1)
assert.deepStrictEqual(decodeSyncMessage(message).changes.length, 5)
//assert.deepStrictEqual(patch.diffs.props, {y: {'5@def456': {type: 'value', value: 4, datatype: 'int'}}}) // changes arrived
// n2 applies the changes and sends confirmation ending the exchange
;[n2, s2] = Automerge.receiveSyncMessage(n2, s2, message)
;[s2, message] = Automerge.generateSyncMessage(n2, s2)
//assert.deepStrictEqual(patch.diffs.props, {x: {'5@abc123': {type: 'value', value: 4, datatype: 'int'}}}) // changes arrived
// n1 receives the message and has nothing more to say
;[n1, s1] = Automerge.receiveSyncMessage(n1, s1, message)
;[s1, message] = Automerge.generateSyncMessage(n1, s1)
assert.deepStrictEqual(message, null)
//assert.deepStrictEqual(patch, null) // no changes arrived
// n2 also has nothing left to say
;[s2, message] = Automerge.generateSyncMessage(n2, s2)
assert.deepStrictEqual(message, null)
})
it("should allow simultaneous messages during synchronization", () => {
// create & synchronize two nodes
let n1 = Automerge.init<any>("abc123"),
n2 = Automerge.init<any>("def456")
let s1 = initSyncState(),
s2 = initSyncState()
for (let i = 0; i < 5; i++)
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.x = i))
for (let i = 0; i < 5; i++)
n2 = Automerge.change(n2, { time: 0 }, doc => (doc.y = i))
const head1 = getHeads(n1)[0],
head2 = getHeads(n2)[0]
// both sides report what they have but have no shared peer state
let msg1to2, msg2to1
;[s1, msg1to2] = Automerge.generateSyncMessage(n1, s1)
;[s2, msg2to1] = Automerge.generateSyncMessage(n2, s2)
assert.deepStrictEqual(decodeSyncMessage(msg1to2).changes.length, 0)
assert.deepStrictEqual(
decodeSyncMessage(msg1to2).have[0].lastSync.length,
0
)
assert.deepStrictEqual(decodeSyncMessage(msg2to1).changes.length, 0)
assert.deepStrictEqual(
decodeSyncMessage(msg2to1).have[0].lastSync.length,
0
)
// n1 and n2 receives that message and update sync state but make no patch
;[n1, s1] = Automerge.receiveSyncMessage(n1, s1, msg2to1)
//assert.deepStrictEqual(patch1, null) // no changes arrived, so no patch
;[n2, s2] = Automerge.receiveSyncMessage(n2, s2, msg1to2)
//assert.deepStrictEqual(patch2, null) // no changes arrived, so no patch
// now both reply with their local changes the other lacks
// (standard warning that 1% of the time this will result in a "need" message)
;[s1, msg1to2] = Automerge.generateSyncMessage(n1, s1)
assert.deepStrictEqual(decodeSyncMessage(msg1to2).changes.length, 5)
;[s2, msg2to1] = Automerge.generateSyncMessage(n2, s2)
assert.deepStrictEqual(decodeSyncMessage(msg2to1).changes.length, 5)
// both should now apply the changes and update the frontend
;[n1, s1] = Automerge.receiveSyncMessage(n1, s1, msg2to1)
assert.deepStrictEqual(getMissingDeps(n1), [])
//assert.notDeepStrictEqual(patch1, null)
assert.deepStrictEqual(n1, { x: 4, y: 4 })
;[n2, s2] = Automerge.receiveSyncMessage(n2, s2, msg1to2)
assert.deepStrictEqual(getMissingDeps(n2), [])
//assert.notDeepStrictEqual(patch2, null)
assert.deepStrictEqual(n2, { x: 4, y: 4 })
// The response acknowledges the changes received, and sends no further changes
;[s1, msg1to2] = Automerge.generateSyncMessage(n1, s1)
assert.deepStrictEqual(decodeSyncMessage(msg1to2).changes.length, 0)
;[s2, msg2to1] = Automerge.generateSyncMessage(n2, s2)
assert.deepStrictEqual(decodeSyncMessage(msg2to1).changes.length, 0)
// After receiving acknowledgements, their shared heads should be equal
;[n1, s1] = Automerge.receiveSyncMessage(n1, s1, msg2to1)
;[n2, s2] = Automerge.receiveSyncMessage(n2, s2, msg1to2)
assert.deepStrictEqual(s1.sharedHeads, [head1, head2].sort())
assert.deepStrictEqual(s2.sharedHeads, [head1, head2].sort())
//assert.deepStrictEqual(patch1, null)
//assert.deepStrictEqual(patch2, null)
// We're in sync, no more messages required
;[s1, msg1to2] = Automerge.generateSyncMessage(n1, s1)
;[s2, msg2to1] = Automerge.generateSyncMessage(n2, s2)
assert.deepStrictEqual(msg1to2, null)
assert.deepStrictEqual(msg2to1, null)
// If we make one more change, and start another sync, its lastSync should be updated
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.x = 5))
;[s1, msg1to2] = Automerge.generateSyncMessage(n1, s1)
assert.deepStrictEqual(
decodeSyncMessage(msg1to2).have[0].lastSync,
[head1, head2].sort()
)
})
it("should assume sent changes were recieved until we hear otherwise", () => {
let n1 = Automerge.init<any>("01234567"),
n2 = Automerge.init<any>("89abcdef")
let s1 = initSyncState(),
message: Automerge.SyncMessage | null = null
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.items = []))
;[n1, n2, s1] = sync(n1, n2)
n1 = Automerge.change(n1, { time: 0 }, doc => doc.items.push("x"))
;[s1, message] = Automerge.generateSyncMessage(n1, s1)
if (message != null) {
assert.deepStrictEqual(decodeSyncMessage(message).changes.length, 1)
}
n1 = Automerge.change(n1, { time: 0 }, doc => doc.items.push("y"))
;[s1, message] = Automerge.generateSyncMessage(n1, s1)
if (message != null) {
assert.deepStrictEqual(decodeSyncMessage(message).changes.length, 1)
}
n1 = Automerge.change(n1, { time: 0 }, doc => doc.items.push("z"))
;[s1, message] = Automerge.generateSyncMessage(n1, s1)
if (message != null) {
assert.deepStrictEqual(decodeSyncMessage(message).changes.length, 1)
}
})
it("should work regardless of who initiates the exchange", () => {
// create & synchronize two nodes
let n1 = Automerge.init<any>(),
n2 = Automerge.init<any>()
let s1 = initSyncState(),
s2 = initSyncState()
for (let i = 0; i < 5; i++)
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.x = i))
;[n1, n2, s1, s2] = sync(n1, n2, s1, s2)
// modify the first node further
for (let i = 5; i < 10; i++)
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.x = i))
assert.notDeepStrictEqual(n1, n2)
;[n1, n2, s1, s2] = sync(n1, n2, s1, s2)
assert.deepStrictEqual(n1, n2)
})
})
})
describe("with diverged documents", () => {
it("should work without prior sync state", () => {
// Scenario: ,-- c10 <-- c11 <-- c12 <-- c13 <-- c14
// c0 <-- c1 <-- c2 <-- c3 <-- c4 <-- c5 <-- c6 <-- c7 <-- c8 <-- c9 <-+
// `-- c15 <-- c16 <-- c17
// lastSync is undefined.
// create two peers both with divergent commits
let n1 = Automerge.init<any>("01234567"),
n2 = Automerge.init<any>("89abcdef")
for (let i = 0; i < 10; i++)
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.x = i))
;[n1, n2] = sync(n1, n2)
for (let i = 10; i < 15; i++)
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.x = i))
for (let i = 15; i < 18; i++)
n2 = Automerge.change(n2, { time: 0 }, doc => (doc.x = i))
assert.notDeepStrictEqual(n1, n2)
;[n1, n2] = sync(n1, n2)
assert.deepStrictEqual(getHeads(n1), getHeads(n2))
assert.deepStrictEqual(n1, n2)
})
it("should work with prior sync state", () => {
// Scenario: ,-- c10 <-- c11 <-- c12 <-- c13 <-- c14
// c0 <-- c1 <-- c2 <-- c3 <-- c4 <-- c5 <-- c6 <-- c7 <-- c8 <-- c9 <-+
// `-- c15 <-- c16 <-- c17
// lastSync is c9.
// create two peers both with divergent commits
let n1 = Automerge.init<any>("01234567"),
n2 = Automerge.init<any>("89abcdef")
let s1 = initSyncState(),
s2 = initSyncState()
for (let i = 0; i < 10; i++)
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.x = i))
;[n1, n2, s1, s2] = sync(n1, n2, s1, s2)
for (let i = 10; i < 15; i++)
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.x = i))
for (let i = 15; i < 18; i++)
n2 = Automerge.change(n2, { time: 0 }, doc => (doc.x = i))
s1 = decodeSyncState(encodeSyncState(s1))
s2 = decodeSyncState(encodeSyncState(s2))
assert.notDeepStrictEqual(n1, n2)
;[n1, n2, s1, s2] = sync(n1, n2, s1, s2)
assert.deepStrictEqual(getHeads(n1), getHeads(n2))
assert.deepStrictEqual(n1, n2)
})
it("should ensure non-empty state after sync", () => {
let n1 = Automerge.init<any>("01234567"),
n2 = Automerge.init<any>("89abcdef")
let s1 = initSyncState(),
s2 = initSyncState()
for (let i = 0; i < 3; i++)
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.x = i))
;[n1, n2, s1, s2] = sync(n1, n2, s1, s2)
assert.deepStrictEqual(s1.sharedHeads, getHeads(n1))
assert.deepStrictEqual(s2.sharedHeads, getHeads(n1))
})
it("should re-sync after one node crashed with data loss", () => {
// Scenario: (r) (n2) (n1)
// c0 <-- c1 <-- c2 <-- c3 <-- c4 <-- c5 <-- c6 <-- c7 <-- c8
// n2 has changes {c0, c1, c2}, n1's lastSync is c5, and n2's lastSync is c2.
// we want to successfully sync (n1) with (r), even though (n1) believes it's talking to (n2)
let n1 = Automerge.init<any>("01234567"),
n2 = Automerge.init<any>("89abcdef")
let s1 = initSyncState(),
s2 = initSyncState()
// n1 makes three changes, which we sync to n2
for (let i = 0; i < 3; i++)
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.x = i))
;[n1, n2, s1, s2] = sync(n1, n2, s1, s2)
// save a copy of n2 as "r" to simulate recovering from crash
let r, rSyncState
;[r, rSyncState] = [Automerge.clone(n2), s2]
// sync another few commits
for (let i = 3; i < 6; i++)
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.x = i))
;[n1, n2, s1, s2] = sync(n1, n2, s1, s2)
// everyone should be on the same page here
assert.deepStrictEqual(getHeads(n1), getHeads(n2))
assert.deepStrictEqual(n1, n2)
// now make a few more changes, then attempt to sync the fully-up-to-date n1 with the confused r
for (let i = 6; i < 9; i++)
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.x = i))
s1 = decodeSyncState(encodeSyncState(s1))
rSyncState = decodeSyncState(encodeSyncState(rSyncState))
assert.notDeepStrictEqual(getHeads(n1), getHeads(r))
assert.notDeepStrictEqual(n1, r)
assert.deepStrictEqual(n1, { x: 8 })
assert.deepStrictEqual(r, { x: 2 })
;[n1, r, s1, rSyncState] = sync(n1, r, s1, rSyncState)
assert.deepStrictEqual(getHeads(n1), getHeads(r))
assert.deepStrictEqual(n1, r)
})
it("should resync after one node experiences data loss without disconnecting", () => {
let n1 = Automerge.init<any>("01234567"),
n2 = Automerge.init<any>("89abcdef")
let s1 = initSyncState(),
s2 = initSyncState()
// n1 makes three changes, which we sync to n2
for (let i = 0; i < 3; i++)
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.x = i))
;[n1, n2, s1, s2] = sync(n1, n2, s1, s2)
assert.deepStrictEqual(getHeads(n1), getHeads(n2))
assert.deepStrictEqual(n1, n2)
let n2AfterDataLoss = Automerge.init("89abcdef")
// "n2" now has no data, but n1 still thinks it does. Note we don't do
// decodeSyncState(encodeSyncState(s1)) in order to simulate data loss without disconnecting
;[n1, n2, s1, s2] = sync(n1, n2AfterDataLoss, s1, initSyncState())
assert.deepStrictEqual(getHeads(n1), getHeads(n2))
assert.deepStrictEqual(n1, n2)
})
it("should handle changes concurrent to the last sync heads", () => {
let n1 = Automerge.init<any>("01234567"),
n2 = Automerge.init<any>("89abcdef"),
n3 = Automerge.init<any>("fedcba98")
let s12 = initSyncState(),
s21 = initSyncState(),
s23 = initSyncState(),
s32 = initSyncState()
// Change 1 is known to all three nodes
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.x = 1))
;[n1, n2, s12, s21] = sync(n1, n2, s12, s21)
;[n2, n3, s23, s32] = sync(n2, n3, s23, s32)
// Change 2 is known to n1 and n2
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.x = 2))
;[n1, n2, s12, s21] = sync(n1, n2, s12, s21)
// Each of the three nodes makes one change (changes 3, 4, 5)
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.x = 3))
n2 = Automerge.change(n2, { time: 0 }, doc => (doc.x = 4))
n3 = Automerge.change(n3, { time: 0 }, doc => (doc.x = 5))
// Apply n3's latest change to n2. If running in Node, turn the Uint8Array into a Buffer, to
// simulate transmission over a network (see https://github.com/automerge/automerge/pull/362)
let change = Automerge.getLastLocalChange(n3)
if (typeof Buffer === "function" && change != null)
change = Buffer.from(change)
;[n2] = (change && Automerge.applyChanges(n2, [change])) || [n2]
// Now sync n1 and n2. n3's change is concurrent to n1 and n2's last sync heads
;[n1, n2, s12, s21] = sync(n1, n2, s12, s21)
assert.deepStrictEqual(getHeads(n1), getHeads(n2))
assert.deepStrictEqual(n1, n2)
})
it("should handle histories with lots of branching and merging", () => {
let n1 = Automerge.init<any>("01234567"),
n2 = Automerge.init<any>("89abcdef"),
n3 = Automerge.init<any>("fedcba98")
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.x = 0))
;[n2] = Automerge.applyChanges(n2, [Automerge.getLastLocalChange(n1)!])
;[n3] = Automerge.applyChanges(n3, [Automerge.getLastLocalChange(n1)!])
n3 = Automerge.change(n3, { time: 0 }, doc => (doc.x = 1))
// - n1c1 <------ n1c2 <------ n1c3 <-- etc. <-- n1c20 <------ n1c21
// / \/ \/ \/
// / /\ /\ /\
// c0 <---- n2c1 <------ n2c2 <------ n2c3 <-- etc. <-- n2c20 <------ n2c21
// \ /
// ---------------------------------------------- n3c1 <-----
for (let i = 1; i < 20; i++) {
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.n1 = i))
n2 = Automerge.change(n2, { time: 0 }, doc => (doc.n2 = i))
const change1 = Automerge.getLastLocalChange(n1)
const change2 = Automerge.getLastLocalChange(n2)
;[n1] = Automerge.applyChanges(n1, [change2!])
;[n2] = Automerge.applyChanges(n2, [change1!])
}
let s1 = initSyncState(),
s2 = initSyncState()
;[n1, n2, s1, s2] = sync(n1, n2, s1, s2)
// Having n3's last change concurrent to the last sync heads forces us into the slower code path
;[n2] = Automerge.applyChanges(n2, [Automerge.getLastLocalChange(n3)!])
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.n1 = "final"))
n2 = Automerge.change(n2, { time: 0 }, doc => (doc.n2 = "final"))
;[n1, n2, s1, s2] = sync(n1, n2, s1, s2)
assert.deepStrictEqual(getHeads(n1), getHeads(n2))
assert.deepStrictEqual(n1, n2)
})
})
describe("with false positives", () => {
// NOTE: the following tests use brute force to search for Bloom filter false positives. The
// tests make change hashes deterministic by fixing the actorId and change timestamp to be
// constants. The loop that searches for false positives is then initialised such that it finds
// a false positive on its first iteration. However, if anything changes about the encoding of
// changes (causing their hashes to change) or if the Bloom filter configuration is changed,
// then the false positive will no longer be the first loop iteration. The tests should still
// pass because the loop will run until a false positive is found, but they will be slower.
it("should handle a false-positive head", () => {
// Scenario: ,-- n1
// c0 <-- c1 <-- c2 <-- c3 <-- c4 <-- c5 <-- c6 <-- c7 <-- c8 <-- c9 <-+
// `-- n2
// where n2 is a false positive in the Bloom filter containing {n1}.
// lastSync is c9.
let n1 = Automerge.init<any>("01234567"),
n2 = Automerge.init<any>("89abcdef")
let s1 = initSyncState(),
s2 = initSyncState()
for (let i = 0; i < 10; i++)
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.x = i))
;[n1, n2, s1, s2] = sync(n1, n2)
for (let i = 1; ; i++) {
// search for false positive; see comment above
const n1up = Automerge.change(
Automerge.clone(n1, { actor: "01234567" }),
{ time: 0 },
doc => (doc.x = `${i} @ n1`)
)
const n2up = Automerge.change(
Automerge.clone(n2, { actor: "89abcdef" }),
{ time: 0 },
doc => (doc.x = `${i} @ n2`)
)
if (new BloomFilter(getHeads(n1up)).containsHash(getHeads(n2up)[0])) {
n1 = n1up
n2 = n2up
break
}
}
const allHeads = [...getHeads(n1), ...getHeads(n2)].sort()
s1 = decodeSyncState(encodeSyncState(s1))
s2 = decodeSyncState(encodeSyncState(s2))
;[n1, n2, s1, s2] = sync(n1, n2, s1, s2)
assert.deepStrictEqual(getHeads(n1), allHeads)
assert.deepStrictEqual(getHeads(n2), allHeads)
})
describe("with a false-positive dependency", () => {
let n1, n2, s1, s2, n1hash2, n2hash2
beforeEach(() => {
// Scenario: ,-- n1c1 <-- n1c2
// c0 <-- c1 <-- c2 <-- c3 <-- c4 <-- c5 <-- c6 <-- c7 <-- c8 <-- c9 <-+
// `-- n2c1 <-- n2c2
// where n2c1 is a false positive in the Bloom filter containing {n1c1, n1c2}.
// lastSync is c9.
n1 = Automerge.init<any>("01234567")
n2 = Automerge.init<any>("89abcdef")
s1 = initSyncState()
s2 = initSyncState()
for (let i = 0; i < 10; i++)
n1 = Automerge.change(n1, { time: 0 }, (doc: any) => (doc.x = i))
;[n1, n2, s1, s2] = sync(n1, n2)
let n1hash1, n2hash1
for (let i = 29; ; i++) {
// search for false positive; see comment above
const n1us1 = Automerge.change(
Automerge.clone(n1, { actor: "01234567" }),
{ time: 0 },
(doc: any) => (doc.x = `${i} @ n1`)
)
const n2us1 = Automerge.change(
Automerge.clone(n2, { actor: "89abcdef" }),
{ time: 0 },
(doc: any) => (doc.x = `${i} @ n2`)
)
n1hash1 = getHeads(n1us1)[0]
n2hash1 = getHeads(n2us1)[0]
const n1us2 = Automerge.change(
n1us1,
{ time: 0 },
(doc: any) => (doc.x = "final @ n1")
)
const n2us2 = Automerge.change(
n2us1,
{ time: 0 },
(doc: any) => (doc.x = "final @ n2")
)
n1hash2 = getHeads(n1us2)[0]
n2hash2 = getHeads(n2us2)[0]
if (new BloomFilter([n1hash1, n1hash2]).containsHash(n2hash1)) {
n1 = n1us2
n2 = n2us2
break
}
}
})
it("should sync two nodes without connection reset", () => {
;[n1, n2, s1, s2] = sync(n1, n2, s1, s2)
assert.deepStrictEqual(getHeads(n1), [n1hash2, n2hash2].sort())
assert.deepStrictEqual(getHeads(n2), [n1hash2, n2hash2].sort())
})
// FIXME - this has a periodic failure
it("should sync two nodes with connection reset", () => {
s1 = decodeSyncState(encodeSyncState(s1))
s2 = decodeSyncState(encodeSyncState(s2))
;[n1, n2, s1, s2] = sync(n1, n2, s1, s2)
assert.deepStrictEqual(getHeads(n1), [n1hash2, n2hash2].sort())
assert.deepStrictEqual(getHeads(n2), [n1hash2, n2hash2].sort())
})
it.skip("should sync three nodes", () => {
s1 = decodeSyncState(encodeSyncState(s1))
s2 = decodeSyncState(encodeSyncState(s2))
// First n1 and n2 exchange Bloom filters
let m1, m2
;[s1, m1] = Automerge.generateSyncMessage(n1, s1)
;[s2, m2] = Automerge.generateSyncMessage(n2, s2)
;[n1, s1] = Automerge.receiveSyncMessage(n1, s1, m2)
;[n2, s2] = Automerge.receiveSyncMessage(n2, s2, m1)
// Then n1 and n2 send each other their changes, except for the false positive
;[s1, m1] = Automerge.generateSyncMessage(n1, s1)
;[s2, m2] = Automerge.generateSyncMessage(n2, s2)
;[n1, s1] = Automerge.receiveSyncMessage(n1, s1, m2)
;[n2, s2] = Automerge.receiveSyncMessage(n2, s2, m1)
assert.strictEqual(decodeSyncMessage(m1).changes.length, 2) // n1c1 and n1c2
assert.strictEqual(decodeSyncMessage(m2).changes.length, 1) // only n2c2; change n2c1 is not sent
// n3 is a node that doesn't have the missing change. Nevertheless n1 is going to ask n3 for it
let n3 = Automerge.init("fedcba98"),
s13 = initSyncState(),
s31 = initSyncState()
;[n1, n3, s13, s31] = sync(n1, n3, s13, s31)
assert.deepStrictEqual(getHeads(n1), [n1hash2])
assert.deepStrictEqual(getHeads(n3), [n1hash2])
})
})
it("should not require an additional request when a false-positive depends on a true-negative", () => {
// Scenario: ,-- n1c1 <-- n1c2 <-- n1c3
// c0 <-- c1 <-- c2 <-- c3 <-- c4 <-+
// `-- n2c1 <-- n2c2 <-- n2c3
// where n2c2 is a false positive in the Bloom filter containing {n1c1, n1c2, n1c3}.
// lastSync is c4.
let n1 = Automerge.init<any>("01234567"),
n2 = Automerge.init<any>("89abcdef")
let s1 = initSyncState(),
s2 = initSyncState()
let n1hash3, n2hash3
for (let i = 0; i < 5; i++)
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.x = i))
;[n1, n2, s1, s2] = sync(n1, n2)
for (let i = 86; ; i++) {
// search for false positive; see comment above
const n1us1 = Automerge.change(
Automerge.clone(n1, { actor: "01234567" }),
{ time: 0 },
doc => (doc.x = `${i} @ n1`)
)
const n2us1 = Automerge.change(
Automerge.clone(n2, { actor: "89abcdef" }),
{ time: 0 },
doc => (doc.x = `${i} @ n2`)
)
const n1hash1 = getHeads(n1us1)[0]
const n1us2 = Automerge.change(
n1us1,
{ time: 0 },
doc => (doc.x = `${i + 1} @ n1`)
)
const n2us2 = Automerge.change(
n2us1,
{ time: 0 },
doc => (doc.x = `${i + 1} @ n2`)
)
const n1hash2 = getHeads(n1us2)[0],
n2hash2 = getHeads(n2us2)[0]
const n1up3 = Automerge.change(
n1us2,
{ time: 0 },
doc => (doc.x = "final @ n1")
)
const n2up3 = Automerge.change(
n2us2,
{ time: 0 },
doc => (doc.x = "final @ n2")
)
n1hash3 = getHeads(n1up3)[0]
n2hash3 = getHeads(n2up3)[0]
if (
new BloomFilter([n1hash1, n1hash2, n1hash3]).containsHash(n2hash2)
) {
n1 = n1up3
n2 = n2up3
break
}
}
const bothHeads = [n1hash3, n2hash3].sort()
s1 = decodeSyncState(encodeSyncState(s1))
s2 = decodeSyncState(encodeSyncState(s2))
;[n1, n2, s1, s2] = sync(n1, n2, s1, s2)
assert.deepStrictEqual(getHeads(n1), bothHeads)
assert.deepStrictEqual(getHeads(n2), bothHeads)
})
it("should handle chains of false-positives", () => {
// Scenario: ,-- c5
// c0 <-- c1 <-- c2 <-- c3 <-- c4 <-+
// `-- n2c1 <-- n2c2 <-- n2c3
// where n2c1 and n2c2 are both false positives in the Bloom filter containing {c5}.
// lastSync is c4.
let n1 = Automerge.init<any>("01234567"),
n2 = Automerge.init<any>("89abcdef")
let s1 = initSyncState(),
s2 = initSyncState()
for (let i = 0; i < 5; i++)
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.x = i))
;[n1, n2, s1, s2] = sync(n1, n2, s1, s2)
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.x = 5))
for (let i = 2; ; i++) {
// search for false positive; see comment above
const n2us1 = Automerge.change(
Automerge.clone(n2, { actor: "89abcdef" }),
{ time: 0 },
doc => (doc.x = `${i} @ n2`)
)
if (new BloomFilter(getHeads(n1)).containsHash(getHeads(n2us1)[0])) {
n2 = n2us1
break
}
}
for (let i = 141; ; i++) {
// search for false positive; see comment above
const n2us2 = Automerge.change(
Automerge.clone(n2, { actor: "89abcdef" }),
{ time: 0 },
doc => (doc.x = `${i} again`)
)
if (new BloomFilter(getHeads(n1)).containsHash(getHeads(n2us2)[0])) {
n2 = n2us2
break
}
}
n2 = Automerge.change(n2, { time: 0 }, doc => (doc.x = "final @ n2"))
const allHeads = [...getHeads(n1), ...getHeads(n2)].sort()
s1 = decodeSyncState(encodeSyncState(s1))
s2 = decodeSyncState(encodeSyncState(s2))
;[n1, n2, s1, s2] = sync(n1, n2, s1, s2)
assert.deepStrictEqual(getHeads(n1), allHeads)
assert.deepStrictEqual(getHeads(n2), allHeads)
})
it("should allow the false-positive hash to be explicitly requested", () => {
// Scenario: ,-- n1
// c0 <-- c1 <-- c2 <-- c3 <-- c4 <-- c5 <-- c6 <-- c7 <-- c8 <-- c9 <-+
// `-- n2
// where n2 causes a false positive in the Bloom filter containing {n1}.
let n1 = Automerge.init<any>("01234567"),
n2 = Automerge.init<any>("89abcdef")
let s1 = initSyncState(),
s2 = initSyncState()
let message
for (let i = 0; i < 10; i++)
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.x = i))
;[n1, n2, s1, s2] = sync(n1, n2)
s1 = decodeSyncState(encodeSyncState(s1))
s2 = decodeSyncState(encodeSyncState(s2))
for (let i = 1; ; i++) {
// brute-force search for false positive; see comment above
const n1up = Automerge.change(
Automerge.clone(n1, { actor: "01234567" }),
{ time: 0 },
doc => (doc.x = `${i} @ n1`)
)
const n2up = Automerge.change(
Automerge.clone(n2, { actor: "89abcdef" }),
{ time: 0 },
doc => (doc.x = `${i} @ n2`)
)
// check if the bloom filter on n2 will believe n1 already has a particular hash
// this will mean n2 won't offer that data to n2 by receiving a sync message from n1
if (new BloomFilter(getHeads(n1up)).containsHash(getHeads(n2up)[0])) {
n1 = n1up
n2 = n2up
break
}
}
// n1 creates a sync message for n2 with an ill-fated bloom
;[s1, message] = Automerge.generateSyncMessage(n1, s1)
assert.strictEqual(decodeSyncMessage(message).changes.length, 0)
// n2 receives it and DOESN'T send a change back
;[n2, s2] = Automerge.receiveSyncMessage(n2, s2, message)
;[s2, message] = Automerge.generateSyncMessage(n2, s2)
assert.strictEqual(decodeSyncMessage(message).changes.length, 0)
// n1 should now realize it's missing that change and request it explicitly
;[n1, s1] = Automerge.receiveSyncMessage(n1, s1, message)
;[s1, message] = Automerge.generateSyncMessage(n1, s1)
assert.deepStrictEqual(decodeSyncMessage(message).need, getHeads(n2))
// n2 should fulfill that request
;[n2, s2] = Automerge.receiveSyncMessage(n2, s2, message)
;[s2, message] = Automerge.generateSyncMessage(n2, s2)
assert.strictEqual(decodeSyncMessage(message).changes.length, 1)
// n1 should apply the change and the two should now be in sync
;[n1, s1] = Automerge.receiveSyncMessage(n1, s1, message)
assert.deepStrictEqual(getHeads(n1), getHeads(n2))
})
})
describe("protocol features", () => {
it("should allow multiple Bloom filters", () => {
// Scenario: ,-- n1c1 <-- n1c2 <-- n1c3
// c0 <-- c1 <-- c2 <-+--- n2c1 <-- n2c2 <-- n2c3
// `-- n3c1 <-- n3c2 <-- n3c3
// n1 has {c0, c1, c2, n1c1, n1c2, n1c3, n2c1, n2c2};
// n2 has {c0, c1, c2, n1c1, n1c2, n2c1, n2c2, n2c3};
// n3 has {c0, c1, c2, n3c1, n3c2, n3c3}.
let n1 = Automerge.init<any>("01234567"),
n2 = Automerge.init<any>("89abcdef"),
n3 = Automerge.init<any>("76543210")
let s13 = initSyncState()
let s32 = initSyncState(),
s31 = initSyncState(),
s23 = initSyncState()
let message1, message2, message3
for (let i = 0; i < 3; i++)
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.x = i))
// sync all 3 nodes
;[n1, n2, ,] = sync(n1, n2) // eslint-disable-line no-unused-vars -- kept for consistency
;[n1, n3, s13, s31] = sync(n1, n3)
;[n3, n2, s32, s23] = sync(n3, n2)
for (let i = 0; i < 2; i++)
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.x = `${i} @ n1`))
for (let i = 0; i < 2; i++)
n2 = Automerge.change(n2, { time: 0 }, doc => (doc.x = `${i} @ n2`))
;[n1] = Automerge.applyChanges(n1, Automerge.getAllChanges(n2))
;[n2] = Automerge.applyChanges(n2, Automerge.getAllChanges(n1))
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.x = `3 @ n1`))
n2 = Automerge.change(n2, { time: 0 }, doc => (doc.x = `3 @ n2`))
for (let i = 0; i < 3; i++)
n3 = Automerge.change(n3, { time: 0 }, doc => (doc.x = `${i} @ n3`))
const n1c3 = getHeads(n1)[0],
n2c3 = getHeads(n2)[0],
n3c3 = getHeads(n3)[0]
s13 = decodeSyncState(encodeSyncState(s13))
s31 = decodeSyncState(encodeSyncState(s31))
s23 = decodeSyncState(encodeSyncState(s23))
s32 = decodeSyncState(encodeSyncState(s32))
// Now n3 concurrently syncs with n1 and n2. Doing this naively would result in n3 receiving
// changes {n1c1, n1c2, n2c1, n2c2} twice (those are the changes that both n1 and n2 have, but
// that n3 does not have). We want to prevent this duplication.
;[s13, message1] = Automerge.generateSyncMessage(n1, s13) // message from n1 to n3
assert.strictEqual(decodeSyncMessage(message1).changes.length, 0)
;[n3, s31] = Automerge.receiveSyncMessage(n3, s31, message1)
;[s31, message3] = Automerge.generateSyncMessage(n3, s31) // message from n3 to n1
assert.strictEqual(decodeSyncMessage(message3).changes.length, 3) // {n3c1, n3c2, n3c3}
;[n1, s13] = Automerge.receiveSyncMessage(n1, s13, message3)
// Copy the Bloom filter received from n1 into the message sent from n3 to n2. This Bloom
// filter indicates what changes n3 is going to receive from n1.
;[s32, message3] = Automerge.generateSyncMessage(n3, s32) // message from n3 to n2
const modifiedMessage = decodeSyncMessage(message3)
modifiedMessage.have.push(decodeSyncMessage(message1).have[0])
assert.strictEqual(modifiedMessage.changes.length, 0)
;[n2, s23] = Automerge.receiveSyncMessage(
n2,
s23,
encodeSyncMessage(modifiedMessage)
)
// n2 replies to n3, sending only n2c3 (the one change that n2 has but n1 doesn't)
;[s23, message2] = Automerge.generateSyncMessage(n2, s23)
assert.strictEqual(decodeSyncMessage(message2).changes.length, 1) // {n2c3}
;[n3, s32] = Automerge.receiveSyncMessage(n3, s32, message2)
// n1 replies to n3
;[s13, message1] = Automerge.generateSyncMessage(n1, s13)
assert.strictEqual(decodeSyncMessage(message1).changes.length, 5) // {n1c1, n1c2, n1c3, n2c1, n2c2}
;[n3, s31] = Automerge.receiveSyncMessage(n3, s31, message1)
assert.deepStrictEqual(getHeads(n3), [n1c3, n2c3, n3c3].sort())
})
it("should allow any change to be requested", () => {
let n1 = Automerge.init<any>("01234567"),
n2 = Automerge.init<any>("89abcdef")
let s1 = initSyncState(),
s2 = initSyncState()
let message: Automerge.SyncMessage | null = null
for (let i = 0; i < 3; i++)
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.x = i))
const lastSync = getHeads(n1)
for (let i = 3; i < 6; i++)
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.x = i))
;[n1, n2, s1, s2] = sync(n1, n2)
s1.lastSentHeads = [] // force generateSyncMessage to return a message even though nothing changed
;[s1, message] = Automerge.generateSyncMessage(n1, s1)
const modMsg = decodeSyncMessage(message!)
modMsg.need = lastSync // re-request change 2
;[n2, s2] = Automerge.receiveSyncMessage(
n2,
s2,
encodeSyncMessage(modMsg)
)
;[s1, message] = Automerge.generateSyncMessage(n2, s2)
assert.strictEqual(decodeSyncMessage(message!).changes.length, 1)
assert.strictEqual(
Automerge.decodeChange(decodeSyncMessage(message!).changes[0]).hash,
lastSync[0]
)
})
it("should ignore requests for a nonexistent change", () => {
let n1 = Automerge.init<any>("01234567"),
n2 = Automerge.init<any>("89abcdef")
let s1 = initSyncState(),
s2 = initSyncState()
let message: Automerge.SyncMessage | null = null
for (let i = 0; i < 3; i++)
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.x = i))
;[n2] = Automerge.applyChanges(n2, Automerge.getAllChanges(n1))
;[s1, message] = Automerge.generateSyncMessage(n1, s1)
const decoded = Automerge.decodeSyncMessage(message!)
decoded.need = [
"0000000000000000000000000000000000000000000000000000000000000000",
]
message = Automerge.encodeSyncMessage(decoded)
;[n2, s2] = Automerge.receiveSyncMessage(n2, s2, message!)
;[s2, message] = Automerge.generateSyncMessage(n2, s2)
assert.strictEqual(message, null)
})
it("should allow a subset of changes to be sent", () => {
// ,-- c1 <-- c2
// c0 <-+
// `-- c3 <-- c4 <-- c5 <-- c6 <-- c7 <-- c8
let n1 = Automerge.init<any>("01234567"),
n2 = Automerge.init<any>("89abcdef"),
n3 = Automerge.init<any>("76543210")
let s1 = initSyncState(),
s2 = initSyncState()
let msg, decodedMsg
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.x = 0))
n3 = Automerge.merge(n3, n1)
for (let i = 1; i <= 2; i++)
n1 = Automerge.change(n1, { time: 0 }, doc => (doc.x = i)) // n1 has {c0, c1, c2}
for (let i = 3; i <= 4; i++)
n3 = Automerge.change(n3, { time: 0 }, doc => (doc.x = i)) // n3 has {c0, c3, c4}
const c2 = getHeads(n1)[0],
c4 = getHeads(n3)[0]
n2 = Automerge.merge(n2, n3) // n2 has {c0, c3, c4}
// Sync n1 and n2, so their shared heads are {c2, c4}
;[n1, n2, s1, s2] = sync(n1, n2)
s1 = decodeSyncState(encodeSyncState(s1))
s2 = decodeSyncState(encodeSyncState(s2))
assert.deepStrictEqual(s1.sharedHeads, [c2, c4].sort())
assert.deepStrictEqual(s2.sharedHeads, [c2, c4].sort())
// n2 and n3 apply {c5, c6, c7, c8}
n3 = Automerge.change(n3, { time: 0 }, doc => (doc.x = 5))
const change5 = Automerge.getLastLocalChange(n3)
n3 = Automerge.change(n3, { time: 0 }, doc => (doc.x = 6))
const change6 = Automerge.getLastLocalChange(n3),
c6 = getHeads(n3)[0]
for (let i = 7; i <= 8; i++)
n3 = Automerge.change(n3, { time: 0 }, doc => (doc.x = i))
const c8 = getHeads(n3)[0]
n2 = Automerge.merge(n2, n3)
// Now n1 initiates a sync with n2, and n2 replies with {c5, c6}. n2 does not send {c7, c8}
;[s1, msg] = Automerge.generateSyncMessage(n1, s1)
;[n2, s2] = Automerge.receiveSyncMessage(n2, s2, msg)
;[s2, msg] = Automerge.generateSyncMessage(n2, s2)
decodedMsg = decodeSyncMessage(msg)
decodedMsg.changes = [change5, change6]
msg = encodeSyncMessage(decodedMsg)
const sentHashes = [
Automerge.decodeChange(change5!).hash,
Automerge.decodeChange(change6!).hash,
]
s2.sentHashes = sentHashes
;[n1, s1] = Automerge.receiveSyncMessage(n1, s1, msg)
assert.deepStrictEqual(s1.sharedHeads, [c2, c6].sort())
// n1 replies, confirming the receipt of {c5, c6} and requesting the remaining changes
;[s1, msg] = Automerge.generateSyncMessage(n1, s1)
;[n2, s2] = Automerge.receiveSyncMessage(n2, s2, msg)
assert.deepStrictEqual(decodeSyncMessage(msg).need, [c8])
assert.deepStrictEqual(
decodeSyncMessage(msg).have[0].lastSync,
[c2, c6].sort()
)
assert.deepStrictEqual(s1.sharedHeads, [c2, c6].sort())
assert.deepStrictEqual(s2.sharedHeads, [c2, c6].sort())
// n2 sends the remaining changes {c7, c8}
;[s2, msg] = Automerge.generateSyncMessage(n2, s2)
;[n1, s1] = Automerge.receiveSyncMessage(n1, s1, msg)
assert.strictEqual(decodeSyncMessage(msg).changes.length, 2)
assert.deepStrictEqual(s1.sharedHeads, [c2, c8].sort())
})
})
})
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