feat(oxfmt): Support oxfmt --migrate [prettier] (Rust side)

[leaysgur]

Part of #15849

Usage: [-c=PATH] [PATH]...

Mode Options:
        --init               Initialize `.oxfmtrc.json` with default values
        --lsp                Start language server protocol (LSP) server
        --migrate=SOURCE     Migrate configuration to `.oxfmtrc.json` from specified source
                             Available sources: prettier

...

At this point, do nothing and just exit. The JS side will be in the next PR.

[leaysgur]

• feat(oxfmt): Support oxfmt --migrate prettier (JS side) #16773
• feat(oxfmt): Support oxfmt --migrate [prettier] (Rust side) #16771 👈 (View in Graphite)
• main

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[charliecreates]

--migrate is wired through parsing correctly, but the NAPI dispatch currently ignores the parsed MigrateSource and always returns "migrate:prettier", which is a maintainability trap as sources expand. The supported-source list is duplicated between help text and parse error, making it easy to drift. Minor readability concern: separator comments (// ---) add noise without clear value.

Additional notes (1)

• Maintainability | apps/oxfmt/src/cli/command.rs:76-83
  The --migrate option is implemented as .argument::<String>("SOURCE") with a custom .parse(...) that lowercases and validates. This works, but the error message and help text can be tightened to match CLI conventions and reduce future duplication:

• The help string includes a newline and an inline list of supported sources; if sources grow, this becomes easy to forget to update alongside the parser.

• The error string uses Supported: prettier while help uses Available sources: prettier (minor inconsistency).

Consider centralizing the supported sources list in one place (e.g., via MigrateSource::VARIANTS/Display) and using it for both help and parse errors.

Summary of changes

Summary

This PR adds Rust-side CLI plumbing for oxfmt --migrate (behind the napi feature) and updates help snapshots.

Key changes

• CLI parsing (apps/oxfmt/src/cli/command.rs)
  • Introduces a new Mode::Migrate(MigrateSource) variant (napi-only).
  • Adds --migrate=SOURCE option and parses SOURCE (currently supports prettier).
  • Adds MigrateSource enum.
• Public exports (apps/oxfmt/src/cli/mod.rs)
  • Re-exports MigrateSource under cfg(feature = "napi").
• NAPI entrypoint behavior (apps/oxfmt/src/main_napi.rs)
  • Routes Mode::Migrate(_) to a command string currently hardcoded as "migrate:prettier".
• Docs/snapshots
  • Updates CLI help snapshots to include --migrate and its description.

[Copilot]

Pull request overview

This PR adds Rust-side support for the --migrate CLI flag to oxfmt, which will enable migrating Prettier configurations to oxfmt's .oxfmtrc.json format. The implementation follows the existing pattern used by the --init flag, where Rust handles command-line parsing and mode detection while the actual migration logic is implemented on the JavaScript/NAPI side.

Key Changes

• Adds --migrate=SOURCE CLI flag that accepts migration sources (currently only "prettier" is supported)
• Introduces MigrateSource enum to represent different configuration sources
• Updates the Mode enum to include a Migrate(MigrateSource) variant
• Returns "migrate:prettier" mode string to the JS side for actual migration implementation

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
tasks/website_formatter/src/snapshots/cli_terminal.snap	Updates CLI help text snapshot to include the new --migrate option with its description
tasks/website_formatter/src/snapshots/cli.snap	Updates markdown CLI documentation snapshot to include the new --migrate option
apps/oxfmt/src/main_napi.rs	Adds pattern match case for Mode::Migrate(_) to return "migrate:prettier" mode string to JS side
apps/oxfmt/src/cli/mod.rs	Exports MigrateSource enum for NAPI feature builds
apps/oxfmt/src/cli/command.rs	Implements the core functionality: defines MigrateSource enum, adds Migrate variant to Mode enum, and implements command-line parsing with validation for migration sources

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