Fix duplicate enum/type alias exports in types-plugin

[jgclement91]

Jira issue link: EP-7657

When using the enum: true configuration option with openapi-typescript, the types-plugin was generating duplicate exports:

1. Enum declarations from openapi-typescript (e.g., export enum Status)
2. Type aliases from types-plugin (e.g., export type Status = components["schemas"]["Status"])

Description of changes

• Modified src/plugins/types-plugin.ts to detect existing enum declarations using TypeScript's AST API (ts.isEnumDeclaration())
• Added filtering logic to exclude enum names when generating convenience type aliases
• Non-enum schemas continue to receive their type aliases as before (e.g., export type Task = components["schemas"]["Task"])
• Added E2E test in tests/e2e.test.ts with test data file tests/data/enums.yaml to verify enums generate without duplicates
• Fixed toSafeName function to use PascalCase transformation (src/plugins/types-plugin.ts:81-127)
  • Previously stripped special characters: "user-status" → "userstatus"
  • Now uses PascalCase to match openapi-typescript's enum naming: "user-status" → "UserStatus"
  • This ensures the enum filtering logic works correctly for schemas with special characters (hyphens, dots, etc.)
• Enhanced test coverage for enum schemas with special characters
  • Added "user-status" and "task.priority" enum schemas to tests/data/enums.yaml
  • Updated E2E test assertions to verify no duplicate type aliases are generated for these cases
  • This prevents regression where enums with non-identifier characters would still generate duplicate type aliases
• Updated doc reference url (https://openapi-ts.dev/cli#flags)

Breaking changes

No breaking change

Additional checks

• Added new tests that cover the code changes + tested locally

(Had to close the previous PR because of the JIRA validation failing

[Copilot]

Pull request overview

This PR fixes duplicate enum/type alias exports when using the enum: true configuration option with openapi-typescript. Previously, the types-plugin would generate both enum declarations (from openapi-typescript) and type aliases for the same schemas, causing duplicates.

Key Changes:

• Added enum detection logic using TypeScript's AST API to filter out schemas that already have enum declarations
• Updated toSafeName function to use PascalCase transformation (e.g., "user-status" → "UserStatus") to match openapi-typescript's enum naming conventions
• Added comprehensive E2E and unit tests to verify enums generate without duplicate type aliases

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
packages/create-schemas/src/plugins/types-plugin.ts	Added enum detection logic and updated toSafeName to PascalCase for matching enum names
packages/create-schemas/tests/plugins.test.ts	Added unit test for enum filtering and updated expectations for PascalCase naming
packages/create-schemas/tests/generate.test.ts	Updated test expectations to reflect PascalCase naming convention
packages/create-schemas/tests/e2e.test.ts	Added E2E test verifying enums with special characters don't generate duplicate type aliases
packages/create-schemas/tests/data/enums.yaml	Added test OpenAPI schema with various enum types and edge cases
packages/create-schemas/tests/snapshots/e2e.test.ts.snap	Added snapshot for enum generation test output
docs/src/configuration.md	Updated openapi-typescript documentation URL reference

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