tauri-apps/tauri · error

failed to read missing addr file {}: {e}

Error message

failed to read missing addr file {}: {e}

What it means

Panic in the mobile dev runtime support code. During `tauri ios dev`/`tauri android dev`, the CLI-side build step reads the temp file `{TMPDIR}/{identifier}-server-addr` (written by the running tauri CLI dev server) to learn the WebSocket address of the dev server, and read_to_string failure panics here. The identifier comes from the app configuration, so a mismatch yields a different filename than the one that was written.

Source

Thrown at crates/tauri-cli/src/mobile/mod.rs:386

  Ok(OptionsHandle(runtime, handle))
}

fn read_options(config: &ConfigMetadata) -> CliOptions {
  let runtime = tokio::runtime::Runtime::new().unwrap();
  let options = runtime
    .block_on(async move {
      let addr_path = temp_dir().join(format!(
        "{}-server-addr",
        config
          .original_identifier()
          .context("app configuration is missing an identifier")?
      ));
      let (tx, rx) = WsTransportClientBuilder::default()
        .build(
          format!(
            "ws://{}",
            read_to_string(&addr_path).unwrap_or_else(|e| panic!(
              "failed to read missing addr file {}: {e}",
              addr_path.display()
            ))
          )
          .parse()
          .unwrap(),
        )
        .await
        .context("failed to build WebSocket client")?;
      let client: Client = ClientBuilder::default().build_with_tokio(tx, rx);
      let options: CliOptions = client
        .request("options", rpc_params![])
        .await
        .context("failed to request options")?;
      Ok::<CliOptions, Error>(options)
    })
    .expect("failed to read CLI options");

View on GitHub (pinned to 52e4b6e71d)

Solutions

1. Stop all tauri dev processes and re-run `tauri ios dev` / `tauri android dev` from a clean shell so server and build step share one session
2. Keep the app identifier stable in tauri.conf.json while iterating on mobile dev
3. Run the CLI and the IDE/build on the same user without sudo so TMPDIR resolves identically

Example fix

# before
# Xcode step panics: failed to read missing addr file /tmp/com.example.app-server-addr

# after
pkill -f 'tauri.*dev' || true
npx tauri ios dev   # single session writes and reads the same {identifier}-server-addr file

# ensure no orphan dev servers before starting (stale/missing addr file is the usual cause)
pkill -f 'tauri.*dev' || true
ls "${TMPDIR:-/tmp}"/*-server-addr 2>/dev/null && echo 'stale addr file present; previous session crashed?'

When it happens

Trigger: The dev server process died or never wrote the addr file; identifier in tauri.conf.json changed between the CLI run and the Xcode/Gradle build step; TMPDIR differs between the CLI and the build tool process (sudo, sandboxed Xcode service, macOS per-user temp dirs); a second dev session overwrote/removed it.

Common situations: Editing `identifier` mid-session; running Xcode builds with sudo or from a different login session; concurrent `tauri dev` runs on the same app; temp dir cleaners removing the file mid-build.

Related errors

• No external IP detected.
• {} project directory {} doesn't exist. Please run `tauri {}
• failed to read CLI options
• iOS platform not installed
• Target not found

AI-assisted analysis of tauri-apps/tauri@52e4b6e71d (2026-08-20). Data as JSON: /api/errors/8b236f459500bea0. Report an issue: GitHub.