fix: prevent config validation errors from crashing parent app

[dionlow]

Summary

• Fix config validation to not throw errors that could crash parent app
• Update OAuth mutation validation to use promise rejection instead of throw
• All validation errors now flow through error callback pattern

Changes

Config Validation (src/headless/config/types.ts)

Before:

export function toCreateConfigContent(config): ConfigContent {
  if (!isValidCreateConfig(config)) {
    throw new Error("Config must have a provider field for creation");
  }
  return config;
}

After:

export function toCreateConfigContent(config): { data?: ConfigContent; error?: Error } {
  if (!isValidCreateConfig(config)) {
    return { error: new Error("Config must have a provider field for creation") };
  }
  return { data: config };
}

useCreateInstallation Hook

• Now checks configResult.error before using config
• Calls onError callback with validation error instead of letting exception bubble up

useUpdateOauthConnectMutation

• Changed from throw new Error(...) to Promise.reject(new Error(...))
• More explicit about returning rejected promise for React Query to handle

Why

During our error handling audit, we found that toCreateConfigContent was throwing synchronously during user actions (when createInstallation is called). This would bypass the error handling improvements from PR #1387 and could still crash the parent app.

Similarly, the OAuth mutation was throwing inside mutationFn which, while caught by React Query, is better expressed as an explicit Promise rejection.

Related PRs

• feat: improve error handling in headless installation hooks #1387 - Fixed throws in useCreate/Update/DeleteInstallation hooks
• feat: add validation hooks to surface prerequisites for installation mutations #1388 - Added validation hooks to surface prerequisites

Test plan

• Verify createInstallation calls onError when config is missing provider field
• Verify parent app doesn't crash when invalid config is provided
• Verify useUpdateOauthConnectMutation properly rejects when required fields are missing
• Verify error messages are surfaced correctly through callbacks
• Verify build passes with no TypeScript errors

🤖 Generated with Claude Code

[Copilot]

Pull Request Overview

This PR refactors error handling in configuration validation and OAuth mutations to prevent synchronous errors from crashing the parent application. Previously, toCreateConfigContent would throw errors during user actions, bypassing React Query's error handling. The changes convert these throwing functions to return result objects with explicit error fields, ensuring all errors flow through the established callback pattern.

Key Changes:

• Modified toCreateConfigContent to return a result object ({ data?, error? }) instead of throwing
• Updated useCreateInstallation to check for validation errors and route them through the onError callback
• Changed useUpdateOauthConnectMutation to return rejected promises instead of throwing inside mutationFn

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
src/headless/config/types.ts	Changed toCreateConfigContent return type from throwing to result object pattern
src/headless/installation/useCreateInstallation.ts	Added validation check for config errors before creating installation request
src/hooks/mutation/useUpdateOauthConnectMutation.ts	Replaced throw with Promise.reject for validation errors

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