Fix seeks

lib/replicator.js

@@ -972,8 +972,8 @@ class Peer {
       this._remoteContiguousLength = start
     }
 
-    if (start === 0 && drop === false && length > this._remoteContiguousLength) {
-      this._remoteContiguousLength = length
+    if (start === 0 && drop === false) {
+      if (length > this._remoteContiguousLength) this._remoteContiguousLength = length
     } else if (length === 1) {
       const bitfield = this.core.skipBitfield === null ? this.core.bitfield : this.core.skipBitfield
       this.remoteBitfield.set(start, has)
@@ -1095,7 +1095,7 @@ class Peer {
       let index = off + i
       if (index > s.seeker.end) index -= len
 
-      if (this.remoteBitfield.get(index) === false) continue
+      if (this._remoteHasBlock(index) === false) continue
       if (this.core.bitfield.get(index) === true) continue
       if (!this._hasTreeParent(index)) continue
 
@@ -1997,6 +1997,17 @@ module.exports = class Replicator {
   }
 
   _onwant (peer, start, length) {
+    const contig = Math.min(this.core.tree.length, this.core.header.hints.contiguousLength)
+
+    if (start + length < contig || (this.core.tree.length === contig)) {
+      peer.wireRange.send({
+        drop: false,
+        start: 0,
+        length: contig
+      })
+      return
+    }
+
     length = Math.min(length, this.core.tree.length - start)
 
     peer.protomux.cork()

test/remote-length.js

@@ -72,11 +72,6 @@ test('announce-range-on-update flow with big core (multiple bitfield pages)', as
     true,
     'Sanity check: b knows about a'
   )
-  t.is(
-    getPeer(b, a).remoteBitfield._pages.tiny.b[1] != null,
-    true,
-    'Sanity check: there is indeed >1 page'
-  )
 
   await b.get(nrBlocks - 1)
   await new Promise(resolve => setTimeout(resolve, 500))

test/replicate.js

@@ -1614,6 +1614,21 @@ test('merkle-tree signature gets unslabbed', async function (t) {
   )
 })
 
+test('seek against non sparse peer', async function (t) {
+  const a = await create()
+  await a.append(['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n'])
+
+  const b = await create(a.key)
+  replicate(a, b, t)
+
+  await b.get(a.length - 1)
+
+  const [block, offset] = await b.seek(5)
+
+  t.is(block, 5)
+  t.is(offset, 0)
+})
+
 async function waitForRequestBlock (core) {
   while (true) {
     const reqBlock = core.replicator._inflight._requests.find(req => req && req.block)