Fix useSWRInfinite pagination and header support (v8/master)

[tk1024]

This is the same as #2586 but for the master branch.

Problem

The SWR code generator has several type safety and parameter handling issues:

1. Missing Pagination Support: useSWRInfinite implementation doesn't support pagination parameters:

   • swrFn doesn't accept parameters from the key loader
   • Pagination parameters cannot be passed to the API function
   • Makes infinite queries unusable for paginated APIs

2. Function Wrapping Bug: swrKeyLoader is incorrectly wrapped in an arrow function:

   • The wrapper ignores SWR's (pageIndex, previousPageData) arguments
   • Prevents proper pagination logic in infinite queries
   • Required workarounds to fix generated code

3. Missing Headers in useSWRInfinite: When headers: true is enabled, headers are not passed to the swrFn:

   • Headers defined in OpenAPI spec are ignored in infinite queries
   • Causes TypeScript compilation errors when headers are required
   • Runtime errors when API requires headers

4. Missing Headers in Mutation Fetchers: Mutation hooks and fetchers don't include header parameters:

   • useXXXMutation hooks don't accept headers
   • Mutation fetchers don't pass headers to API functions
   • Breaking for APIs that require headers in POST/PUT/DELETE operations

Solution

This PR fixes all issues:

1. Pagination Support: Generates swrFn that accepts pageParams from the key loader with proper type annotation extracted from GetterProp
2. Function Wrapping: Removes the incorrect arrow function wrapper from swrKeyLoader to allow SWR to pass pagination arguments correctly
3. Headers in useSWRInfinite: Includes header parameters in the swrFn between pageParams and options
4. Headers in Mutations: Includes headers in mutation hook signatures, fetcher functions, and properly passes them to API calls

Before

// useSWRInfinite: swrFn doesn't accept parameters and drops headers
const swrFn = () => listPets(params, options);
const swrKeyLoader = () => (isEnabled ? getKeyLoader() : null);

// Mutations: fetchers don't include headers
export const getCreatePetsMutationFetcher = (
  params: CreatePetsParams,
  options?: AxiosRequestConfig,
) => {
  return (_: Key, { arg }: { arg: CreatePetsBody }) => {
    return createPets(arg, params, options); // Missing headers!
  };
};

After

// useSWRInfinite: Type safe pageParams with headers support
const swrFn = ([_url, pageParams]: [string, ListPetsParams & { page: number }]) =>
  listPets(pageParams, headers, options);
const swrKeyLoader = isEnabled ? getKeyLoader() : () => null;

// Mutations: headers properly included
export const getCreatePetsMutationFetcher = (
  params: CreatePetsParams,
  headers: CreatePetsHeaders,
  options?: AxiosRequestConfig,
) => {
  return (_: Key, { arg }: { arg: CreatePetsBody }) => {
    return createPets(arg, params, headers, options); // Headers included!
  };
};

Changes

1. Fix useSWRInfinite swrFn parameter handling

• Separate path parameters (fixed values) from query parameters (pagination values)
• Generate swrFn that accepts ([_url, pageParams]) from the key loader
• Pass parameters correctly: operationName(pathParams, pageParams, options)

2. Add type annotation to pageParams

• Extract type name from GetterProp.definition (e.g., "params: ListPetsParams" → "ListPetsParams")
• Use never as fallback type for better type safety (causes compilation errors if params are missing when expected)
• Enables IDE autocomplete and compile-time type checking

3. Fix swrKeyLoader function wrapping bug

• The original implementation incorrectly wrapped the key loader: () => isEnabled ? getKeyLoader() : null
• This prevented SWR from passing (pageIndex, previousPageData) arguments to the key loader
• Fixed to return the actual key loader function: isEnabled ? getKeyLoader() : () => null
• This allows proper pagination parameter handling in infinite queries

4. Fix headers in useSWRInfinite

• Extract header parameters separately from other props
• Include headers in swrFn generation between pageParams and httpRequestSecondArg
• Ensures proper parameter order: operationName(pageParams, headers, options)

5. Fix headers in mutation fetchers and hooks

• Include GetterPropType.HEADER in swrProps filter for mutation hooks
• Include headers in swrMutationFetcherProperties for fetcher function parameters
• Generate proper parameter lists for both GET and POST/PUT/DELETE mutations
• Maintain correct parameter order: (params, headers, options) for fetcher signatures

6. Add comprehensive tests

• Unit tests for query parameter type extraction logic
• Unit tests for SWR builder functionality
• Regression tests for type safety with strict TypeScript settings
• Regression tests for swrKeyLoader function signature
• Tests for headers in infinite queries, regular queries, and mutations
• Test configuration with headers: true to catch header-related bugs

Testing

All tests pass successfully:

# Unit tests
yarn workspace @orval/swr test
# ✓ 5 tests passed

# Integration tests
yarn test:cli
# ✓ All generated code compiles with strict TypeScript

# Full test suite
yarn test:ci
# ✓ All tests pass

Affected Files

• packages/swr/src/index.ts - Core implementation (pagination, headers, mutations)
• packages/swr/src/client.test.ts - Unit tests for type extraction
• packages/swr/src/index.test.ts - Unit tests for builder
• packages/swr/vitest.config.ts - Test configuration
• packages/swr/package.json - Added test script and vitest dependency
• tests/regressions/swr.ts - Regression tests for type safety and headers
• tests/configs/swr.config.ts - Added petstoreWithHeaders test configuration

Breaking Changes

None. This PR fixes bugs and adds support for features that were previously non-functional:

• useSWRInfinite pagination was broken and unusable
• Headers in mutation fetchers were ignored even when headers: true was configured

After regeneration, previously broken functionality will now work correctly.

Related Issues

Fixes #2106