Duplicate plugins loaded when same plugin exists in multiple sources

[devxoul]

Problem

When the same plugin exists in both opencode.json configuration and the .opencode/plugin/ directory, both instances are loaded and executed, causing duplicate behavior and potential conflicts.

Example Scenario

A user has:

• oh-my-opencode@2.4.3 specified in their opencode.json
• oh-my-opencode.js in their local .opencode/plugin/ directory (perhaps a development version)

Current behavior: Both plugins are loaded and executed, leading to:

• Duplicate side effects
• Potential version conflicts
• Confusing behavior when testing local modifications
• Resource waste from running the same plugin twice

Expected behavior: Only the highest priority plugin should be loaded, with a clear priority hierarchy.

Proposed Solution

Implement plugin deduplication by canonical name with priority-based resolution:

1. Plugin Name Extraction (getPluginName)

Extract a canonical name from various plugin specifier formats:

• file:// URLs: Extract filename without extension
  • file:///path/to/plugin/foo.js → foo
• npm packages: Extract package name without version
  • oh-my-opencode@2.4.3 → oh-my-opencode
• Scoped packages: Preserve scope, remove version
  • @scope/pkg@1.0.0 → @scope/pkg

2. Priority-Based Deduplication (deduplicatePlugins)

When multiple plugins with the same canonical name are found, use this priority order (highest to lowest):

Priority	Source	Rationale
1 (Highest)	Local plugin/ directory	Development/override takes precedence
2	Local opencode.json	Project-specific config
3	Global plugin/ directory	User-wide overrides
4 (Lowest)	Global opencode.json	User-wide defaults

3. Implementation Approach

Since plugins are collected in low-to-high priority order:

1. Reverse the plugin list
2. Deduplicate by canonical name (keeping first occurrence = highest priority)
3. Restore original order

Use Cases

Use Case 1: Local Development Override

Global opencode.json: "oh-my-opencode@2.4.3"
Local plugin/: "oh-my-opencode.js" (modified version)
→ Only local plugin/oh-my-opencode.js is loaded

Use Case 2: Project-Specific Version

Global opencode.json: "@company/plugin@1.0.0"
Local opencode.json: "@company/plugin@2.0.0"
→ Only @company/plugin@2.0.0 from local config is loaded

Use Case 3: No Duplicates

Local opencode.json: "plugin-a", "plugin-b"
→ Both loaded normally (no deduplication needed)

Acceptance Criteria

• getPluginName correctly extracts canonical names from:
  • file:// URLs (with .js and .ts extensions)
  • npm packages with versions
  • Scoped packages with versions
  • Plain package names without versions
• deduplicatePlugins correctly:
  • Removes duplicates by canonical name
  • Preserves highest priority plugin
  • Maintains relative order of unique plugins
• Integration test confirms local plugin overrides global config
• No breaking changes for users without duplicate plugins

Additional Context

• This is a configuration enhancement in packages/opencode/src/config/config.ts
• The fix should be transparent to users who don't have duplicate plugins
• Users with intentional duplicates (e.g., different scoped packages with same base name but different functionality) should not be affected since the canonical name includes the scope

[github-actions]

This issue might be a duplicate of existing issues. Please check:

• bug: plugins are loaded twice #3179: plugins are loaded twice
• [BUG]: Plugin Registering Twice #6596: Plugin Registering Twice
• bug: multiple plugins registering auth for the same provider silently overwrite each other #6261: multiple plugins registering auth for the same provider silently overwrite each other
• Security Issue - Autoloading Repository Plugins #7163: Security Issue - Autoloading Repository Plugins

Feel free to ignore if none of these address your specific case.