Remove literal-address -s dialling; keep only -s mdns: discovery

[chrisuthe]

The Sendspin spec has two ways to connect: the server discovers the player's _sendspin._tcp advertisement, or the player discovers a server on _sendspin-server._tcp and connects to it. Dialling a typed-in host[:port] or ws:// URL is neither, so -s / server = now take only mdns:[<name>].

Breaking: any other -s or server value (host, host:port, ws:// URL, bare mdns, empty) exits 1 at parse time with one error: line that says address dialling was removed and points to -s mdns:[<name>] or being discovered. From a config file it names the file and line. The value is never echoed, since it may hold credentials.

• Remove parse_server_url(), redact_url_userinfo(), USERINFO_MASK, DEFAULT_REMOTE_SERVER_PORT and Options::server_url
• OutboundMode always dials a discovered server; LastDial answers nothing for an empty server_id
• --help, the no-mDNS parse error and the no-mDNS runtime line no longer offer an address
• Drop the smoke test's credential-redaction check
• Update the README, wiki, config example and systemd unit comments; add ROADMAP item 26

-s mdns: behaviour is unchanged: the advertisement is suppressed, browsing and last-server preference work as before, the retry backoff still applies, and SENDSPIN_SERVER_URL is still exported for the dialled server.

Testing

• mDNS build: 417/417 unit tests
• -DSENDSPIN_CLI_WITH_MDNS=OFF build: 416/416 unit tests
• scripts/smoke_test.sh: every check passed
• Checked by hand: each removed form exits 1 without echoing the value, and -s "mdns:Living Room" browses and finds servers on the LAN

[Copilot]

🟢 Approval recommended

The implementation consistently removes literal-address dialing while preserving and testing mDNS discovery behavior.

Pull request overview

Removes literal server dialing and restricts outbound connections to mDNS-discovered servers.

Changes:

• Rejects non-mdns: server values without exposing them.
• Simplifies outbound dialing and URL tracking.
• Updates tests, documentation, examples, and packaging comments.

File summaries

File	Description
src/cli.cpp	Enforces discovery-only server parsing.
src/cli.h	Removes literal-address APIs and state.
src/main.cpp	Always uses discovery for outbound mode.
src/outbound.cpp	Rejects unverifiable dial records.
src/outbound.h	Updates LastDial contract.
src/mdns_common.cpp	Updates IPv6 URL comment.
src/hooks.h	Documents discovery-only URL export.
src/audio_sink.cpp	Removes obsolete parser reference.
tests/cli_test.cpp	Tests address rejection and secrecy.
tests/config_file_test.cpp	Tests configuration behavior.
tests/discovery_test.cpp	Tests updated LastDial semantics.
scripts/smoke_test.sh	Removes obsolete redaction test.
README.md	Documents mDNS-only usage.
packaging/sendspin-cli.service.in	Updates service comment.
packaging/sendspin-cli.conf.example	Updates configuration example.
docs/wiki/Troubleshooting.md	Updates no-mDNS guidance.
docs/wiki/Home.md	Describes discovery-based outbound mode.
docs/wiki/Getting-Started-on-Linux.md	Updates setup instructions.
docs/wiki/Controlling-the-Player.md	Clarifies exported server URL semantics.
docs/wiki/Configuration.md	Documents accepted server values.
docs/wiki/Advanced-Usage.md	Removes address-dialing examples.
docs/ROADMAP.md	Records the shipped breaking change.

Review details

• Files reviewed: 22/22 changed files
• Comments generated: 0
• Review effort level: Balanced

---

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.