/connect in TUI does not persist plugin providers after instance dispose

[luanweslley77]

Description

Bug Summary

OAuth providers registered by plugins via config() hook disappear from the TUI provider list after /instance/dispose, even though:

• Plugin config() hook registers the provider correctly ✅
• Plugin auth.loader() returns valid credentials ✅
• client.auth.set() saves credentials to auth.json ✅
• Provider appears in opencode auth login CLI picker ✅
  The provider only reappears after restarting OpenCode entirely.

Expected Behavior

• Provider should appear in the provider list after OAuth completion
• Models from the provider should be available for selection
• No restart required

Actual Behavior

• Provider does NOT appear in the provider list
• Models from the provider are NOT available
• Provider only appears after fully restarting OpenCode

Workaround

Restart OpenCode entirely after OAuth completion.

Technical Analysis

Root Cause

The issue is in packages/opencode/src/provider/provider.ts in the mergeProvider() function:

function mergeProvider(providerID: ProviderID, provider: Partial<Info>) {
  const existing = providers[providerID]
  if (existing) {
    providers[providerID] = mergeDeep(existing, provider)
    return
  }
  const match = database[providerID]  // ← PROBLEM: Only checks models.dev
  if (!match) return  // ← Returns silently, provider not registered
  providers[providerID] = mergeDeep(match, provider)
}
The database is populated from ModelsDev.get() which only contains providers from models.dev, NOT providers registered by plugins via config() hook.
Timeline
1. Plugin loads → config() hook called
   └─> config.provider["qwen-code"] = { ... } ✅
2. provider.state() created
   └─> database["qwen-code"] = config.provider["qwen-code"] ✅
   └─> mergeProvider("qwen-code", ...) → database["qwen-code"] exists ✅
   └─> Provider registered ✅
3. User executes /connect → OAuth completes
   └─> client.auth.set() saves credentials ✅
   └─> OpenCode triggers /instance/dispose
4. New instance created
   └─> Config re-read from disk
   └─> config.provider["qwen-code"] = undefined ❌ (not persisted in opencode.json)
   └─> database["qwen-code"] = undefined ❌
   └─> mergeProvider("qwen-code", ...) → database["qwen-code"] missing ❌
   └─> Provider NOT registered ❌
Integration Test Results
Created comprehensive integration test (tests/integration/provider-refresh.ts) that confirms:
- ✅ File watcher triggers correctly
- ✅ Token cache invalidates correctly
- ✅ loader() receives valid credentials
- ✅ config() hook registers provider in-memory
- ❌ Provider does not appear in OpenCode provider list after dispose
Conclusion: The problem is NOT in the plugin - it's in OpenCode's provider state management.
Related Issues
- #13917 - Fixed for CLI (opencode auth login) via PR #13921, but TUI still affected
- #13231 - OAuth login methods not presented for plugin providers (still open)
- #18486 - Custom providers do not inherit provider loaders (still open)
Proposed Solutions
Option 1: Add Plugin Providers to database Before mergeProvider
Modify provider.state() to check plugin providers before calling mergeProvider():
for (const plugin of await Plugin.list()) {
  if (!plugin.auth) continue
  const providerID = ProviderID.make(plugin.auth.provider)
  
  // Check if plugin registered provider via config()
  const configProvider = config.provider?.[providerID]
  if (configProvider && !database[providerID]) {
    database[providerID] = fromConfigProvider(configProvider)
  }
  
  // ... rest of existing logic
}
Pros:
- Cleaner separation of concerns
- Doesn't modify user files
Cons:
- Requires OpenCode core changes
- More complex implementation
Option 2: Add API for Plugin Provider Registration
Expose an API for plugins to register providers persistently:
// New plugin API
client.provider.register({
  id: "qwen-code",
  name: "Qwen Code",
  npm: "@ai-sdk/openai-compatible",
  models: { ... }
})
Pros:
- Clean, official API
- Clear intent
Cons:
- Requires OpenCode core changes
- Longest timeline to resolution



### Plugins

opencode-qwencode-auth@git+https://github.com/luanweslley77/opencode-qwencode-auth.git, opencode-gemini-auth@latest 

### OpenCode version

1.3.7

### Steps to reproduce

1. Install plugin: `opencode-qwencode-auth@git+https://github.com/luanweslley77/opencode-qwencode-auth.git`
2. Start OpenCode TUI
3. Execute `/connect` command
4. Select the plugin's provider (e.g., "qwen-code")
5. Complete OAuth flow in browser
6. OAuth completes successfully, credentials saved to `~/.local/share/opencode/auth.json`
7. OpenCode triggers `/instance/dispose` internally
8. New instance is created
9. Execute `/connect` again

### Screenshot and/or share link

/

https://github.com/user-attachments/assets/38dd7924-4564-4f7b-a233-bf132c68d95e
https://github.com/user-attachments/assets/d21dda0a-2343-4db6-b0ec-530e241c2169

### Operating System

Fedora Linux 43 (KDE Plasma Desktop Edition) x86_64

### Terminal

Konsole 

[luanweslley77]

Supporting Evidence

The opencode-gemini-auth plugin works correctly with /connect because its provider ID
is "google", which IS registered in models.dev.
After /instance/dispose, the Gemini provider continues to work because
database["google"] exists in models.dev, so mergeProvider() succeeds.
In contrast, custom providers like "qwen-code" are NOT in models.dev, so
mergeProvider() fails silently after instance disposal.
This confirms the root cause: providers must exist in models.dev OR be added to
the database before mergeProvider() is called.