fix possible dup work on diff change

src/models/StratumV1Client.ts

@@ -58,6 +58,7 @@ export class StratumV1Client {
 
     private buffer: string = '';
     private connectionClosed = false;
+    private lastSentMiningJobTimestamp: number = null;
 
     private miningSubmissionHashes = new Set<string>()
 
@@ -467,6 +468,7 @@ export class StratumV1Client {
         if (!success) {
             return;
         }
+        this.lastSentMiningJobTimestamp = jobTemplate.block.timestamp;
 
 
         //console.log(`Sent new job to ${this.clientAuthorization.worker}.${this.extraNonceAndSessionId}. (clearJobs: ${jobTemplate.blockData.clearJobs}, fee?: ${!this.noFee})`)
@@ -659,9 +661,21 @@ export class StratumV1Client {
             await this.socket.write(data);
 
             const jobTemplate = await firstValueFrom(this.stratumV1JobsService.newMiningJob$);
-            // we need to clear the jobs so that the difficulty set takes effect. Otherwise the different miner implementations can cause issues
-            jobTemplate.blockData.clearJobs = true;
-            await this.sendNewMiningJob(jobTemplate);
+            const nextTimestamp = Math.max(
+                jobTemplate.block.timestamp,
+                Math.floor(Date.now() / 1000),
+                (this.lastSentMiningJobTimestamp ?? 0) + 1
+            );
+            // We need to clear jobs so the difficulty takes effect, but avoid mutating or
+            // re-sending the shared cached template with byte-identical work.
+            const refreshedJobTemplate: IJobTemplate = {
+                ...jobTemplate,
+                block: Object.assign(new bitcoinjs.Block(), jobTemplate.block, {
+                    timestamp: nextTimestamp
+                }),
+                blockData: { ...jobTemplate.blockData, clearJobs: true }
+            };
+            await this.sendNewMiningJob(refreshedJobTemplate);
 
         }
     }

src/services/stratum-v1-jobs.service.spec.ts

@@ -12,6 +12,7 @@ describe('StratumV1JobsService', () => {
 
     const createTemplate = (height = MockRecording1.BLOCK_TEMPLATE.height): IBlockTemplate => ({
         ...MockRecording1.BLOCK_TEMPLATE,
+        transactions: MockRecording1.BLOCK_TEMPLATE.transactions.map(tx => ({ ...tx })),
         height
     });
 
@@ -62,6 +63,34 @@ describe('StratumV1JobsService', () => {
         expect(service.getJobTemplateById(jobTemplate.blockData.id)).toBe(jobTemplate);
     });
 
+    it('should skip identical non-clean template refreshes', async () => {
+        await firstValueFrom(service.newMiningJob$);
+
+        blockTemplate$.next(createTemplate());
+
+        expect(service.latestJobTemplateId).toBe(2);
+        expect(Object.keys(service.blocks)).toHaveLength(1);
+    });
+
+    it('should emit when transaction identity changes without changing transaction count', async () => {
+        await firstValueFrom(service.newMiningJob$);
+
+        const reorderedTemplate = createTemplate();
+        reorderedTemplate.transactions = [
+            reorderedTemplate.transactions[1],
+            reorderedTemplate.transactions[0],
+            ...reorderedTemplate.transactions.slice(2)
+        ];
+
+        const nextTemplate = firstValueFrom(service.newMiningJob$.pipe(skip(1)));
+        blockTemplate$.next(reorderedTemplate);
+        const jobTemplate = await nextTemplate;
+
+        expect(jobTemplate.blockData.clearJobs).toBe(false);
+        expect(jobTemplate.blockData.id).toBe('2');
+        expect(service.getJobTemplateById(jobTemplate.blockData.id)).toBe(jobTemplate);
+    });
+
     it('should age old jobs and templates after five minutes', async () => {
         await firstValueFrom(service.newMiningJob$);
         const oldCreation = Date.now() - (1000 * 60 * 11);
@@ -71,6 +100,7 @@ describe('StratumV1JobsService', () => {
         } as any;
 
         bitcoinRpcService.miningInfo.blocks = MockRecording1.BLOCK_TEMPLATE.height;
+        jest.setSystemTime(new Date(Date.now() + 1000));
         const nextTemplate = firstValueFrom(service.newMiningJob$.pipe(skip(1)));
         blockTemplate$.next(createTemplate());
         const jobTemplate = await nextTemplate;

src/services/stratum-v1-jobs.service.ts

@@ -31,6 +31,7 @@ export class StratumV1JobsService {
     public blocks: { [id: number]: IJobTemplate } = {};
 
     private lastBlockHeight = 0;
+    private lastWorkSignature: string;
 
     constructor(
         private readonly bitcoinRpcService: BitcoinRpcService
@@ -53,13 +54,29 @@ export class StratumV1JobsService {
                 }
 
                 const currentTime = Math.floor(new Date().getTime() / 1000);
+                const timestamp = blockTemplate.mintime > currentTime ? blockTemplate.mintime : currentTime;
+                const workSignature = [
+                    blockTemplate.previousblockhash,
+                    blockTemplate.version,
+                    blockTemplate.bits,
+                    timestamp,
+                    blockTemplate.height,
+                    blockTemplate.coinbasevalue,
+                    ...blockTemplate.transactions.map(tx => tx.hash ?? tx.txid ?? tx.data)
+                ].join('|');
+
+                if (!clearJobs && workSignature === this.lastWorkSignature) {
+                    return null;
+                }
+                this.lastWorkSignature = workSignature;
+
                 return {
                     version: blockTemplate.version,
                     bits: parseInt(blockTemplate.bits, 16),
                     prevHash: this.convertToLittleEndian(blockTemplate.previousblockhash),
                     transactions: blockTemplate.transactions.map(t => bitcoinjs.Transaction.fromHex(t.data)),
                     coinbasevalue: blockTemplate.coinbasevalue,
-                    timestamp: blockTemplate.mintime > currentTime ? blockTemplate.mintime : currentTime,
+                    timestamp,
                     networkDifficulty: this.calculateNetworkDifficulty(parseInt(blockTemplate.bits, 16)),
                     clearJobs,
                     height: blockTemplate.height