typespec1-8  Exercise 2: Fixing Lint Warnings and Failing the Build
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lint.tsp (the chapter's file; the three rules are enabled in tspconfig_lint_strict.yaml, which also has warn-as-error: true):

  import "@typespec/http";
  import "@typespec/versioning";

  using Http;
  using TypeSpec.Versioning;

  @service(#{ title: "Lint Demo" })
  namespace LintDemo;

  model Book { id: string; }

  model Wrapper<T, Spare> { value: T; }

  @route("/shared")
  interface Shared {
    @get ping(): string;
  }

  interface Mine {
    ping is Shared.ping;
  }

  @route("/books")
  interface Books {
    @get list(): Wrapper<Book, string>;
  }

Before: the three warnings (shown in the chapter) and exit code 1 with warn-as-error.

FIX 1 AND 2 (easy): delete 'import "@typespec/versioning"' and 'using TypeSpec.Versioning;', and delete the unused template parameter (Wrapper<T, Spare> becomes Wrapper<T>, and its use becomes Wrapper<Book>).

FIX 3 (my first attempt was wrong). I thought the problem was the missing prefix, so I put @route("/shared") on Mine as well as on Shared. The compiler then reported a genuine error, which is worse than the warning:

  Diagnostics were reported during compilation:

  lintfix.tsp:14:8 - error @typespec/http/duplicate-operation: Duplicate operation "ping" routed at "get /shared".
  > 14 |   @get ping(): string;
       |         ^^^^
  lintfix.tsp:19:3 - error @typespec/http/duplicate-operation: Duplicate operation "ping" routed at "get /shared".
  > 19 |   ping is Shared.ping;
       |    ^^^^

  Found 2 errors.

Two operations on the same verb and path. My second attempt used a different prefix, @route("/mine") on Mine. The lint rule still fired:

  lintfix.tsp:19:3 - error @typespec/http/op-reference-container-route: Operation ping references an operation which has a @route prefix on its namespace or interface: "/shared". ...

(it is an 'error' in that run only because warn-as-error turns warnings into errors.) The rule is not about whether the copy has a route: it fires whenever the ORIGINAL's route is on its container. The third attempt moved the route from Shared's interface to the operation itself, which is carried with 'is':

  import "@typespec/http";

  using Http;

  @service(#{ title: "Lint Demo" })
  namespace LintDemo;

  model Book { id: string; }

  model Wrapper<T> { value: T; }

  interface Shared {
    @route("/shared") @get ping(): string;
  }

  @route("/mine")
  interface Mine {
    ping is Shared.ping;
  }

  @route("/books")
  interface Books {
    @get list(): Wrapper<Book>;
  }

Compiled with the strict config: 'Compilation completed successfully.', exit code 0.
The resulting paths, from the OpenAPI output: /books, /mine/shared and /shared. Mine.ping got the prefix of its own interface plus the route that came with the operation.

WHY THIS WORKS AS AN ANSWER
---------------------------
The first two fixes are mechanical. The third shows why the rule exists: the two obvious repairs for a lint warning (copy the route, give a different route) either break the API or leave the warning. Keeping the route on the operation, where 'is' carries it, is what the rule is pushing you toward.