Colon suffix in path segment (AIP-136 custom method, e.g. /v1/items:search) becomes a phantom required path param

[denis-markushin]

Description

A colon inside a path segment is treated as an Express-style path parameter. Routes that use AIP-136 custom methods, such as /v1/items:search or /v1/items/{itemId}:archive, come out with a required string argument that the spec does not declare. The colon suffix is also removed from the URL template.

This looks like the same problem as #532, which was filed as a question and is still open.

Version: 13.12.6. parseRouteName on main is unchanged.

Reproduction

{
  "openapi": "3.0.3",
  "info": { "title": "repro", "version": "1.0.0" },
  "paths": {
    "/v1/items:search": {
      "post": {
        "operationId": "searchItems",
        "responses": { "200": { "description": "ok" } }
      }
    },
    "/v1/items/{itemId}:archive": {
      "post": {
        "operationId": "archiveItem",
        "parameters": [
          { "name": "itemId", "in": "path", "required": true, "schema": { "type": "string" } }
        ],
        "responses": { "200": { "description": "ok" } }
      }
    }
  }
}

await generateApi({ input: "spec.json", output: false, httpClientType: "fetch" });

Actual

searchItems: (search: string, params: RequestParams = {}) =>
  this.request<void, any>({
    path: `/v1/items${search}`,
    method: "POST",
    ...params,
  }),
archiveItem: (itemId: string, archive: string, params: RequestParams = {}) =>
  this.request<void, any>({
    path: `/v1/items/${itemId}${archive}`,
    method: "POST",
    ...params,
  }),

searchItems() requires an argument that has no meaning in the spec. If the caller passes a value, it is appended to the URL as is. The only argument that gives the correct URL is the literal ":search".

Expected

searchItems: (params: RequestParams = {}) =>
  this.request<void, any>({ path: `/v1/items:search`, method: "POST", ...params }),
archiveItem: (itemId: string, params: RequestParams = {}) =>
  this.request<void, any>({ path: `/v1/items/${itemId}:archive`, method: "POST", ...params }),

Cause and a possible fix

In src/schema-routes/schema-routes.ts, parseRouteName matches a colon parameter at any position:

/({[\w[\\\]^`][-_.\w]*})|(:[\w[\\\]^`][-_.\w]*:?)/g

An Express-style parameter always starts a path segment. Requiring a preceding / keeps /users/:userId working and stops matching custom-method suffixes:

/({[\w[\\\]^`][-_.\w]*})|((?<=\/):[\w[\\\]^`][-_.\w]*:?)/g

route	current	with lookbehind
/v1/items:search	[":search"]	none
/v1/items/{itemId}:archive	["{itemId}", ":archive"]	["{itemId}"]
/users/:userId	[":userId"]	[":userId"]
/users/:userId/posts/:postId	[":userId", ":postId"]	[":userId", ":postId"]

Workaround

We use an onCreateRoute hook. It finds path params whose $match starts with :, puts the literal back into request.path, and removes the param from request.parameters and from requestParams.typeData.content.