bug: port = 0 does not work because the actual bound port is never exposed

[jiz4oh]

Did you read the documentation and check existing issues?

• I have read all the documentations (README, :h livepreview, Wiki)
• I have updated the plugin to the latest version before submitting this issue
• I have searched the existing issues and closed issues issues

Neovim version (nvim -v)

0.12.3

Operating system/version

macos 26.6

Browser/version

149.0.7827.200

Describe the bug

live-preview.nvim currently accepts a configured port, but port = 0 does not work as expected.

On systems where binding to port 0 should let the OS choose an ephemeral port, the plugin still keeps using the configured value 0 afterward when it:

• checks whether the port is already in use
• builds the preview URL
• opens the browser
• reports health/runtime state

As a result, users cannot use port = 0 to request a random available port, and the final assigned port is not exposed anywhere.

Using port = 0 is a standard way to avoid fixed-port conflicts, especially in:

• remote development
• SSH sessions
• multiple concurrent Neovim instances
• environments where a static preview port is frequently occupied

Steps To Reproduce

1. Clone the plugin git clone https://github.com/brianhuster/live-preview.nvim
2. Open Nvim with minimal repro file nvim -u minimal_init.lua
3. ...

Expected Behavior

• The server should bind successfully on an OS-assigned ephemeral port.
• The plugin should discover the effective port after bind/listen.
• The browser should open the real URL, for example http://127.0.0.1:54321/....
• The effective port should be available to users, for example through plugin state or a public API.

Health

livepreview:                                                              1 ❌

- ❌ ERROR No healthcheck found for "livepreview" plugin.

Minimal config to reproduce

vim.cmd.set "rtp+=/path/to/live-preview.nvim"

require("livepreview.config").set({
  address = "127.0.0.1",
  port = 0,
})

[github-actions]

Thank you for your issue! We appreciate your feedback and will look into it as soon as possible. Please make sure to include all necessary details (including a minimal config that can reproduce the error) to help us assist you better. Pull requests are also welcome!