Support bitcoin-0.19.1

[araspitzu]

Update our regtests to use bitcoin-0.19.1, the most notable changes in this release are about fees (especially the CPFP-carve out rule for the dual-anchor commitment format). There are also some RPC changes: the fundrawtransaction RPC does not fail when providing a too little feerate but instead bitcoin will fail when broadcasting the transaction with sendrawtransaction, the error message is also changed.

I replaced the URLs for our bitcoin-core test instance with bitcoincore.org which is quite faster than bitcoin.org

[sstone]

I think that the impact of recent fee policy changes should be documented in this PR: do we need to change how we create funding transactions ? can funding transactions be created but not published ? Do users need to take any action ?

[araspitzu]

Right, so here is the gist of the fee policy changes in the new bitcoin release:

• CPFP carve-out: allows for one extra ancestor in the CPFP "package" of transactions, this relaxes the mempool acceptance constraints to allow the dual-anchor design. We don't have to take action for this.
• -maxtxfee parameter in fundrawtransaction: this is a hard limit set by default to 0.1BTC to the maximum fee payable by a transaction created via RPC, we don't have to take action for this as our transactions are (hopefully) paying less than 0.1BTC, although it's worth to bear this parameter in mind.

One notable change for eclair are the RPCs fundrawtransction and sendrawtransaction, it's a bit undocumented in the release notes but their behavior has slightly changed. fundrawtransaction does not fail anymore if the feerate is too low, instead bitcoin-core will fail to broadcast it (with sendrawtransaction) if it doesn't meet the criteria to enter the mempool, this means that transactions can be created but not published (the min-fee parameters are unchanged in this release and it's still 253 sat/kw). Users don't have to take any action nor we need to change the way the transactions are created because we correctly handle failure to publish transactions.

[t-bast]

Our README still mentions that we need at least bitcoin core 0.17.1, do we want to update that to a more recent version? And our wiki?

[pm47]

@sstone please confirm that you have checked the hashes + sigs.

[pm47]

Our README still mentions that we need at least bitcoin core 0.17.1, do we want to update that to a more recent version? And our wiki?

Good point, we should recommend what we test.

[araspitzu]

Our README still mentions that we need at least bitcoin core 0.17.1, do we want to update that to a more recent version? And our wiki?

Good point, we should recommend what we test.

Do we want to drop support to 0.17.1? I've been using 0.18 for quite some time in my personal instance, i suggest to update the README saying we support 0.18 and 0.19 but we recommend 0.18, WDYT?

[pm47]

Do we want to drop support to 0.17.1? I've been using 0.18 for quite some time in my personal instance, i suggest to update the README saying we support 0.18 and 0.19 but we recommend 0.18, WDYT?

But we could be breaking compatibility with 0.17.1 and 0.18 tomorrow without noticing, because we are not testing them. I have no strong opinion on this though.

[sstone]

@pm47 Yes I've checked all hashes
Good point about the readme which I think should be updated to 0.18.1 and higher (I'm in favor of dropping support for older versions)

[araspitzu]

I updated the README to support explicitly 0.18.1 and 0.19.1, so when 0.20 is out we don't get caught off-guard :), both supported versions are actively tested either by running eclair on mainnet with 0.18.1 or using the 0.19.1 it in the tests.

[codecov-io]

Codecov Report

Merging #1380 into master will increase coverage by 0.29%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1380      +/-   ##
==========================================
+ Coverage   86.45%   86.75%   +0.29%     
==========================================
  Files         123      123              
  Lines        9357     9427      +70     
  Branches      405      403       -2     
==========================================
+ Hits         8090     8178      +88     
+ Misses       1267     1249      -18     

Impacted Files	Coverage Δ
...eclair/blockchain/bitcoind/BitcoinCoreWallet.scala	87.50% <0.00%> (-1.39%)	⬇️
...la/fr/acinq/eclair/transactions/Transactions.scala	96.38% <0.00%> (-0.51%)	⬇️
...c/main/scala/fr/acinq/eclair/channel/Helpers.scala	95.84% <0.00%> (-0.47%)	⬇️
...main/scala/fr/acinq/eclair/io/PeerConnection.scala	83.48% <0.00%> (-0.31%)	⬇️
...e/src/main/scala/fr/acinq/eclair/router/Sync.scala	98.38% <0.00%> (+0.10%)	⬆️
...src/main/scala/fr/acinq/eclair/router/Router.scala	94.30% <0.00%> (+0.29%)	⬆️
...c/main/scala/fr/acinq/eclair/channel/Channel.scala	85.90% <0.00%> (+0.60%)	⬆️
...nq/eclair/blockchain/electrum/ElectrumClient.scala	74.55% <0.00%> (+0.71%)	⬆️
...q/eclair/blockchain/electrum/ElectrumWatcher.scala	55.20% <0.00%> (+1.60%)	⬆️
...main/scala/fr/acinq/eclair/router/Validation.scala	92.57% <0.00%> (+1.63%)	⬆️
... and 3 more