plugins: config-entry options silently ignored when the spec duplicates an auto-discovered local plugin

Summary

A plugins config entry that targets a local plugin package also auto-discovered from the global plugins directory registers a second instance with the same plugin id when the package spec uses forward slashes on Windows. The second instance fails with Duplicate plugin ID: <id>, and its options are silently ignored — the plugin runs with defaults and nothing tells the user the options were dropped.

Environment

• opencode version: 2.0.2
• OS: Windows 11 (10.0.26220.9343, win32 x64)
• Terminal: Unavailable: reproduced against the background service via opencode api (no TUI attached)
• Shell: cmd.exe
• Install/channel: latest (2.0.2)
• Active plugins: 4 local entries auto-discovered from ~/.config/opencode/plugins/; no plugins key in the global config at rest (the test entry was removed after the repro)

Reproduction

1. Create a local plugin package at ~/.config/opencode/plugins/example/ whose index.ts default-exports Plugin.define({ id: "example", setup(ctx) { /* register a tool that returns JSON.stringify(ctx.options) */ } }).

2. Add a global config entry using an absolute path with forward slashes:

   {
     "plugins": [
       { "package": "C:/Users/<user>/.config/opencode/plugins/example", "options": { "foo": "bar" } }
     ]
   }
   

3. Let the config reload, then inspect the plugin list — opencode api get /api/plugin:

   • two entries with id: "example": the first status: "active", the second status: "failed" with "error": "Duplicate plugin ID: example";
   • the running plugin reports ctx.options === {} — the configured options never arrive.

4. Change the spec to the same directory with native separators (C:\Users\<user>\.config\opencode\plugins\example) or to a config-relative path ("./plugins/example"): the list shows exactly one active entry, and ctx.options is { "foo": "bar" }.

Expected Behavior

At least one of:

• path specs are canonicalized before duplicate detection, so the config entry dedupes against the auto-discovered package and its options are applied; or
• the entry's options are merged into the already-loaded instance; or
• at minimum, the dropped options are surfaced as a warning.

Actual Behavior

The config entry produces a rejected duplicate (Duplicate plugin ID: example) while the option-less auto-discovered instance keeps running. Options are silently dropped; the only trace is a failed entry in /api/plugin, and the server log shows only msg="loading plugin" lines with no warning.

Additional Context

• Verified repeatedly in both directions: forward-slash absolute path → duplicate + options ignored; backslash absolute or config-relative → single instance + options applied.
• Related: #7427 fixed duplicate loading in V1 via canonical-name dedupe; the V2 behavior above shows spec canonicalization still misses Windows separator styles.
• Impact: forward-slash absolute paths are a common cross-platform spelling, so users can silently lose plugin options — the plugin still works, just without its configuration, which is hard to notice.
• Workaround: write absolute specs with native separators, or use a path relative to the config file when the package sits beside it.