Failure to bind to ZMQ addresses is swallowed in debug logs

### Is there an existing issue for this?

- [x] I have searched the existing issues

### Current behaviour

When failing to bind to specified ZMQ addresses due to them already being in use, the error is completely swallowed up when not running with debug logs. 

### Expected behaviour

I'd expect one of two things to happen:

1. Bitcoin Core exiting with a non-zero status code and a clear message saying what happened (I'd prefer this)
2. An error message in the logs, that is visible without having to enable debug logs. 

### Steps to reproduce

1. Spawn a node with one of the ZMQ arguments provided: `bitcoind -regtest -noconf -datadir=(mktemp -d) -rpcuser=user -rpcpassword=password -rpcport=18888 -port=17777 -zmqpubrawblock=tcp://localhost:10000`
2. Spawn a second node with the same ZMQ argument(s): `bitcoind -regtest -noconf -datadir=(mktemp -d) -rpcuser=user -rpcpassword=password -rpcport=18889 -port=17778 -zmqpubrawblock=tcp://localhost:10000`
3. Observe that both nodes run just fine, but that just the first one is able to bind to the ZMQ address:
   ```
   ❯ bitcoin-cli -rpcport=18888 -rpcuser=user -rpcpassword=password getzmqnotifications
   [
      {
        "type": "pubrawblock",
        "address": "tcp://localhost:10000",
        "hwm": 1000
      }
    ]

    ❯ bitcoin-cli -rpcport=18889 -rpcuser=user -rpcpassword=password getzmqnotifications
    [
    ]
    ```
4. Observe that no clear warnings/errors are produced from the second node. 

### Relevant log output

<details>

❯ bitcoind -regtest -noconf -datadir=(mktemp -d) -rpcuser=user -rpcpassword=password -rpcport=18889 -port=17778 -zmqpubrawblock=tcp://localhost:10000
2025-10-27T17:10:29Z Bitcoin Core version v29.0.0 (release build)
2025-10-27T17:10:29Z Using the 'arm_shani(1way,2way)' SHA256 implementation
2025-10-27T17:10:29Z Default data directory /Users/torkel/Library/Application Support/Bitcoin
2025-10-27T17:10:29Z Using data directory /var/folders/91/w34lrpx12hl46htkt8l7ntph0000gn/T/tmp.0w5H0uf0Uy/regtest
2025-10-27T17:10:29Z Config file: <disabled>
2025-10-27T17:10:29Z Command-line arg: conf=false
2025-10-27T17:10:29Z Command-line arg: datadir="/var/folders/91/w34lrpx12hl46htkt8l7ntph0000gn/T/tmp.0w5H0uf0Uy"
2025-10-27T17:10:29Z Command-line arg: port="17778"
2025-10-27T17:10:29Z Command-line arg: regtest=""
2025-10-27T17:10:29Z Command-line arg: rpcpassword=****
2025-10-27T17:10:29Z Command-line arg: rpcport="18889"
2025-10-27T17:10:29Z Command-line arg: rpcuser=****
2025-10-27T17:10:29Z Command-line arg: zmqpubrawblock="tcp://localhost:10000"
2025-10-27T17:10:29Z Using at most 125 automatic connections (285 file descriptors available)
2025-10-27T17:10:29Z scheduler thread start
2025-10-27T17:10:29Z Binding RPC on address ::1 port 18889
2025-10-27T17:10:29Z Binding RPC on address 127.0.0.1 port 18889
2025-10-27T17:10:29Z Config options rpcuser and rpcpassword will soon be deprecated. Locally-run instances may remove rpcuser to use cookie-based auth, or may be replaced with rpcauth. Please see share/rpcauth for rpcauth auth generation.
2025-10-27T17:10:29Z Starting HTTP server with 16 worker threads
2025-10-27T17:10:29Z Using wallet directory /var/folders/91/w34lrpx12hl46htkt8l7ntph0000gn/T/tmp.0w5H0uf0Uy/regtest/wallets
2025-10-27T17:10:29Z init message: Verifying wallet(s)…
2025-10-27T17:10:29Z Using /16 prefix for IP bucketing
2025-10-27T17:10:29Z init message: Loading P2P addresses…
2025-10-27T17:10:29Z Creating peers.dat because the file was not found ("/var/folders/91/w34lrpx12hl46htkt8l7ntph0000gn/T/tmp.0w5H0uf0Uy/regtest/peers.dat")
2025-10-27T17:10:29Z init message: Loading banlist…
2025-10-27T17:10:29Z Recreating the banlist database
2025-10-27T17:10:29Z SetNetworkActive: true
2025-10-27T17:10:29Z /var/folders/91/w34lrpx12hl46htkt8l7ntph0000gn/T/tmp.0w5H0uf0Uy/regtest/fee_estimates.dat is not found. Continue anyway.
2025-10-27T17:10:29Z Cache configuration:
2025-10-27T17:10:29Z * Using 2.0 MiB for block index database
2025-10-27T17:10:29Z * Using 8.0 MiB for chain state database
2025-10-27T17:10:29Z * Using 440.0 MiB for in-memory UTXO set (plus up to 286.1 MiB of unused mempool space)
2025-10-27T17:10:29Z Script verification uses 11 additional threads
2025-10-27T17:10:29Z Using obfuscation key for blocksdir *.dat files (/var/folders/91/w34lrpx12hl46htkt8l7ntph0000gn/T/tmp.0w5H0uf0Uy/regtest/blocks): 'e386ebca6b3ba7e8'
2025-10-27T17:10:29Z Opening LevelDB in /var/folders/91/w34lrpx12hl46htkt8l7ntph0000gn/T/tmp.0w5H0uf0Uy/regtest/blocks/index
2025-10-27T17:10:29Z Opened LevelDB successfully
2025-10-27T17:10:29Z Using obfuscation key for /var/folders/91/w34lrpx12hl46htkt8l7ntph0000gn/T/tmp.0w5H0uf0Uy/regtest/blocks/index: 0000000000000000
2025-10-27T17:10:29Z Using 16 MiB out of 16 MiB requested for signature cache, able to store 524288 elements
2025-10-27T17:10:29Z Using 16 MiB out of 16 MiB requested for script execution cache, able to store 524288 elements
2025-10-27T17:10:29Z init message: Loading block index…
2025-10-27T17:10:29Z Validating signatures for all blocks.
2025-10-27T17:10:29Z Setting nMinimumChainWork=0000000000000000000000000000000000000000000000000000000000000000
2025-10-27T17:10:29Z LoadBlockIndexDB: last block file = 0
2025-10-27T17:10:29Z LoadBlockIndexDB: last block file info: CBlockFileInfo(blocks=0, size=0, heights=0...0, time=1970-01-01...1970-01-01)
2025-10-27T17:10:29Z Checking all blk files are present...
2025-10-27T17:10:29Z Initializing chainstate Chainstate [ibd] @ height -1 (null)
2025-10-27T17:10:29Z Opening LevelDB in /var/folders/91/w34lrpx12hl46htkt8l7ntph0000gn/T/tmp.0w5H0uf0Uy/regtest/chainstate
2025-10-27T17:10:29Z Opened LevelDB successfully
2025-10-27T17:10:29Z Wrote new obfuscate key for /var/folders/91/w34lrpx12hl46htkt8l7ntph0000gn/T/tmp.0w5H0uf0Uy/regtest/chainstate: 224e6c7c34b6b019
2025-10-27T17:10:29Z Using obfuscation key for /var/folders/91/w34lrpx12hl46htkt8l7ntph0000gn/T/tmp.0w5H0uf0Uy/regtest/chainstate: 224e6c7c34b6b019
2025-10-27T17:10:29Z init message: Verifying blocks…
2025-10-27T17:10:29Z Block index and chainstate loaded
2025-10-27T17:10:29Z Setting NODE_NETWORK on non-prune mode
2025-10-27T17:10:29Z initload thread start
2025-10-27T17:10:29Z UpdateTip: new best=0f9188f13cb7b2c71f2a335e3a4fc328bf5beb436012afca590b1a11466e2206 height=0 version=0x00000001 log2_work=1.000000 tx=1 date='2011-02-02T23:16:42Z' progress=1.000000 cache=0.3MiB(0txo)
2025-10-27T17:10:29Z block tree size = 1
2025-10-27T17:10:29Z nBestHeight = 0
2025-10-27T17:10:29Z Failed to open mempool file. Continuing anyway.
2025-10-27T17:10:29Z initload thread exit
2025-10-27T17:10:29Z torcontrol thread start
2025-10-27T17:10:29Z Bound to 127.0.0.1:17779
2025-10-27T17:10:29Z Bound to [::]:17778
2025-10-27T17:10:29Z Bound to 0.0.0.0:17778
2025-10-27T17:10:29Z 0 block-relay-only anchors will be tried for connections.
2025-10-27T17:10:29Z init message: Starting network threads…
2025-10-27T17:10:29Z net thread start
2025-10-27T17:10:29Z dnsseed thread start
2025-10-27T17:10:29Z addcon thread start
2025-10-27T17:10:29Z msghand thread start
2025-10-27T17:10:29Z Loading addresses from DNS seed dummySeed.invalid.
2025-10-27T17:10:29Z init message: Done loading
2025-10-27T17:10:29Z opencon thread start
2025-10-27T17:10:29Z 0 addresses found from DNS seeds
2025-10-27T17:10:29Z dnsseed thread exit

❯ bitcoind -regtest -noconf -datadir=(mktemp -d) -rpcuser=user -rpcpassword=password -rpcport=18889 -port=17778 -zmqpubrawblock=tcp://localhost:10000 -debug
2025-10-27T17:12:31Z Bitcoin Core version v29.0.0 (release build)
2025-10-27T17:12:31Z Using the 'arm_shani(1way,2way)' SHA256 implementation
2025-10-27T17:12:31Z [rand] Feeding 22886 bytes of environment data into RNG
2025-10-27T17:12:31Z Default data directory /Users/torkel/Library/Application Support/Bitcoin
2025-10-27T17:12:31Z Using data directory /var/folders/91/w34lrpx12hl46htkt8l7ntph0000gn/T/tmp.DuVJxjyfXp/regtest
2025-10-27T17:12:31Z Config file: <disabled>
2025-10-27T17:12:31Z Command-line arg: conf=false
2025-10-27T17:12:31Z Command-line arg: datadir="/var/folders/91/w34lrpx12hl46htkt8l7ntph0000gn/T/tmp.DuVJxjyfXp"
2025-10-27T17:12:31Z Command-line arg: debug=""
2025-10-27T17:12:31Z Command-line arg: port="17778"
2025-10-27T17:12:31Z Command-line arg: regtest=""
2025-10-27T17:12:31Z Command-line arg: rpcpassword=****
2025-10-27T17:12:31Z Command-line arg: rpcport="18889"
2025-10-27T17:12:31Z Command-line arg: rpcuser=****
2025-10-27T17:12:31Z Command-line arg: zmqpubrawblock="tcp://localhost:10000"
2025-10-27T17:12:31Z Using at most 125 automatic connections (285 file descriptors available)
2025-10-27T17:12:31Z scheduler thread start
2025-10-27T17:12:31Z [http] Allowing HTTP connections from: 127.0.0.0/8 ::1/128
2025-10-27T17:12:31Z Binding RPC on address ::1 port 18889
2025-10-27T17:12:31Z [libevent] event_add: event: 0x6000025c8038 (fd 10), EV_READ    call 0x100dee7b0
2025-10-27T17:12:31Z [libevent] Bound to port 18889 - Awaiting connections ...
2025-10-27T17:12:31Z Binding RPC on address 127.0.0.1 port 18889
2025-10-27T17:12:31Z [libevent] event_add: event: 0x6000025c80f8 (fd 11), EV_READ    call 0x100dee7b0
2025-10-27T17:12:31Z [libevent] Bound to port 18889 - Awaiting connections ...
2025-10-27T17:12:31Z [http] Initialized HTTP server
2025-10-27T17:12:31Z [http] creating work queue of depth 64
2025-10-27T17:12:31Z [rpc] Starting RPC
2025-10-27T17:12:31Z [rpc] Starting HTTP RPC server
2025-10-27T17:12:31Z Config options rpcuser and rpcpassword will soon be deprecated. Locally-run instances may remove rpcuser to use cookie-based auth, or may be replaced with rpcauth. Please see share/rpcauth for rpcauth auth generation.
2025-10-27T17:12:31Z [http] Registering HTTP handler for / (exactmatch 1)
2025-10-27T17:12:31Z [http] Registering HTTP handler for /wallet/ (exactmatch 0)
2025-10-27T17:12:31Z Starting HTTP server with 16 worker threads
2025-10-27T17:12:31Z [http] Entering http event loop
2025-10-27T17:12:31Z Using wallet directory /var/folders/91/w34lrpx12hl46htkt8l7ntph0000gn/T/tmp.DuVJxjyfXp/regtest/wallets
2025-10-27T17:12:31Z init message: Verifying wallet(s)…
2025-10-27T17:12:31Z Using /16 prefix for IP bucketing
2025-10-27T17:12:31Z init message: Loading P2P addresses…
2025-10-27T17:12:31Z Creating peers.dat because the file was not found ("/var/folders/91/w34lrpx12hl46htkt8l7ntph0000gn/T/tmp.DuVJxjyfXp/regtest/peers.dat")
2025-10-27T17:12:31Z init message: Loading banlist…
2025-10-27T17:12:31Z Recreating the banlist database
2025-10-27T17:12:31Z [net] Flushed 0 banned node addresses/subnets to disk  0ms
2025-10-27T17:12:31Z [net] setting try another outbound peer=false
2025-10-27T17:12:31Z SetNetworkActive: true
2025-10-27T17:12:31Z /var/folders/91/w34lrpx12hl46htkt8l7ntph0000gn/T/tmp.DuVJxjyfXp/regtest/fee_estimates.dat is not found. Continue anyway.
2025-10-27T17:12:31Z [zmq] version 4.3.5
2025-10-27T17:12:31Z [zmq] Initialize notification interface
2025-10-27T17:12:31Z [zmq] Outbound message high water mark for pubrawblock at tcp://localhost:10000 is 1000
2025-10-27T17:12:31Z [zmq] Error: Failed to bind address, msg: Address already in use
2025-10-27T17:12:31Z [zmq] Notifier pubrawblock failed (address = tcp://localhost:10000)
2025-10-27T17:12:31Z [zmq] Shutdown notification interface
2025-10-27T17:12:31Z [zmq] Shutdown notifier pubrawblock at tcp://localhost:10000
</details>

### How did you obtain Bitcoin Core

Pre-built binaries

### What version of Bitcoin Core are you using?

v29.0.0

### Operating system and version

MacOS 15.6

### Machine specifications

_No response_


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Uh oh!

Failure to bind to ZMQ addresses is swallowed in debug logs #33715

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Failure to bind to ZMQ addresses is swallowed in debug logs #33715

Description

Is there an existing issue for this?

Current behaviour

Expected behaviour

Steps to reproduce

Relevant log output

How did you obtain Bitcoin Core

What version of Bitcoin Core are you using?

Operating system and version

Machine specifications

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Issue actions