From c9f2891da1d8513f6890a77f7cba3624a3669485 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Miroslav=20Bajto=C5=A1?= <oss@bajtos.net>
Date: Wed, 6 Aug 2025 18:13:48 +0200
Subject: [PATCH 1/2] fix: publish empty batches to avoid staled rounds
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After we changed the 0k checker node to run all task as quickly as
possible, we are hitting a deadlock where no measurements are reported
towards the end of the round, and as a result, the round is never
advanced.

In this patch, I am changing the publisher to commit a CID for an empty
file (bafkqaaa) when no measurements were recorded.

Signed-off-by: Miroslav Bajtoš <oss@bajtos.net>
---
 publish/index.js     | 26 +++++++++++++++++---------
 publish/test/test.js | 43 +++++++++++++++++++++++++++++++++++++------
 2 files changed, 54 insertions(+), 15 deletions(-)

diff --git a/publish/index.js b/publish/index.js
index 9f34d7d2..14a0ed94 100644
--- a/publish/index.js
+++ b/publish/index.js
@@ -44,8 +44,9 @@ export const publish = async ({
     maxMeasurements
   ])
   if (measurements.length === 0) {
-    logger.log('No measurements to publish.')
-    return
+    // IMPORTANT: We still need to publish an empty batch,
+    // otherwise the current round will never advance.
+    logger.log('WARNING: No measurements to publish. Publishing an empty batch.')
   }
 
   // Fetch the count of all unpublished measurements - we need this for monitoring
@@ -53,18 +54,25 @@ export const publish = async ({
   // measurements in between the previous and the next query.
   const totalCount = (await pgPool.query(
     'SELECT COUNT(*) FROM measurements'
-  )).rows[0].count
+  )).rows[0]?.count || 0
 
   logger.log(`Publishing ${measurements.length} measurements. Total unpublished: ${totalCount}. Batch size: ${maxMeasurements}.`)
 
   // Share measurements
   const start = new Date()
-  const file = new File(
-    [measurements.map(m => JSON.stringify(m)).join('\n')],
-    'measurements.ndjson',
-    { type: 'application/json' }
-  )
-  const cid = await web3Storage.uploadFile(file)
+
+  let cid
+  if (measurements.length) {
+    const file = new File(
+      [measurements.map(m => JSON.stringify(m)).join('\n')],
+      'measurements.ndjson',
+      { type: 'application/json' }
+    )
+    cid = await web3Storage.uploadFile(file)
+  } else {
+    // bafkqaaa is a CID for an empty file
+    cid = 'bafkqaaa'
+  }
   const uploadMeasurementsDuration = new Date().getTime() - start.getTime()
   logger.log(`Measurements packaged in ${cid}`)
 
diff --git a/publish/test/test.js b/publish/test/test.js
index 000bd381..34be20c6 100644
--- a/publish/test/test.js
+++ b/publish/test/test.js
@@ -14,7 +14,7 @@ import {
 
 describe('unit', () => {
   it('publishes', async () => {
-    const cid = 'bafybeicmyzlxgqeg5lgjgnzducj37s7bxhxk6vywqtuym2vhqzxjtymqvm'
+    const cid = 'bafkqaaa'
 
     const clientStatements = []
     const clientQueryParams = []
@@ -109,7 +109,7 @@ describe('unit', () => {
     assert.strictEqual(removeConfirmedCalls.length, 1)
   })
 
-  it('noops when measurements empty', async () => {
+  it('publishes an empty batch with CID bafkqaaa when measurements empty', async () => {
     const clientStatements = []
     const client = {
       connect () {
@@ -122,9 +122,40 @@ describe('unit', () => {
       }
     }
 
-    const web3Storage = {}
-    const ieContract = {}
-    const stuckTransactionsCanceller = {}
+    const web3Storage = {
+      async uploadFile (file) {
+        throw new Error('web3Storage.uploadFile should not be called')
+      }
+    }
+
+    const ieContractMeasurementCIDs = []
+    const ieContract = {
+      async addMeasurements (cid) {
+        ieContractMeasurementCIDs.push(cid)
+        return {
+          async wait () {
+            return {
+              logs: [{}]
+            }
+          }
+        }
+      },
+      interface: {
+        parseLog () {
+          return {
+            args: [
+              null,
+              1
+            ]
+          }
+        }
+      }
+    }
+
+    const stuckTransactionsCanceller = {
+      async addPending (tx) { },
+      async removeConfirmed (tx) { }
+    }
 
     const { recordTelemetry } = createTelemetryRecorderStub()
 
@@ -138,7 +169,7 @@ describe('unit', () => {
       stuckTransactionsCanceller
     })
 
-    assert.strictEqual(clientStatements.length, 1)
+    assert.deepStrictEqual(ieContractMeasurementCIDs, ['bafkqaaa'])
   })
 })
 

From 2725cd0ec03557237d078788148feb3961f085fb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Miroslav=20Bajto=C5=A1?= <oss@bajtos.net>
Date: Wed, 6 Aug 2025 18:42:00 +0200
Subject: [PATCH 2/2] Update publish/test/test.js

---
 publish/test/test.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/publish/test/test.js b/publish/test/test.js
index 34be20c6..d0dcfb37 100644
--- a/publish/test/test.js
+++ b/publish/test/test.js
@@ -14,7 +14,7 @@ import {
 
 describe('unit', () => {
   it('publishes', async () => {
-    const cid = 'bafkqaaa'
+    const cid = 'bafybeicmyzlxgqeg5lgjgnzducj37s7bxhxk6vywqtuym2vhqzxjtymqvm'
 
     const clientStatements = []
     const clientQueryParams = []