fix: merge plugin selections (resolves #4565)

[ariane-emory]

Resolves #4565.

I stumbled onto a version of 4565 myself while I was messing around editing opencode's source: when I launched opencode in it's own source directory, my bell plugin at ~/.config/opencode/plugin/bell.ts (just plays a sound when the session idles, nothing fancy) stopped making noise. After poking around a bit, I discovered that this was a consequence of opencode/.opencode/opencode.jsonc specifying plugin selections, which were replacing (instead of being combined with) my own globally selected plugins.

This PR fixes that, merging the globally selected plugins with those selected locally in the project.

[rekram1-node]

can we undo this? Whyd we change it

[rekram1-node]

ditto?

[rekram1-node]

2 nits but looks good

[ariane-emory]

Not sure why or how that file changed, I will revert it back to match HEAD.

[ariane-emory]

Done.

[rekram1-node]

/oc update the plugin merging so that it uses a set to prevent duplicates

[opencode-agent]

Excellent! All typechecks pass. Let me create a summary of what was changed:

Summary

I've successfully updated the plugin merging logic in /home/runner/work/opencode/opencode/packages/opencode/src/config/config.ts to use a Set for deduplication. Here's what was changed:

Changes Made

File: packages/opencode/src/config/config.ts

• Line 29: Modified the mergeConfigWithPlugins function to use a Set for plugin deduplication
• Before: merged.plugin = [...target.plugin, ...source.plugin]
• After:

  const pluginSet = new Set([...target.plugin, ...source.plugin])
  merged.plugin = Array.from(pluginSet)

File: packages/opencode/test/config/config.test.ts

• Added new test: "deduplicates duplicate plugins from global and local configs" to verify the deduplication functionality works correctly

Benefits

1. Prevents duplicate plugins: When the same plugin appears in both global and local configs, it will only be loaded once
2. Maintains existing behavior: All unique plugins from both configs are still merged and loaded
3. Performance improvement: Avoids loading the same plugin multiple times
4. Backward compatibility: No breaking changes to the API or configuration format

Verification

• ✅ All existing tests pass (18/18)
• ✅ New deduplication test passes
• ✅ Type checking passes for all packages
• ✅ No linting issues

The change is minimal, focused, and maintains the existing plugin merging behavior while adding deduplication to prevent duplicates as requested.

opencode session  |  github run

[rekram1-node]

Thank you!