fix(graphql): rewrap late-added resolvers

[Farhan-Abbas]

GraphQL Instrumentation: Fix Missing Spans for Late-Added Resolvers

Which problem is this PR solving?

Fixes #3362. Custom resolvers on GraphQL Query and Mutation types are not being instrumented when using Apollo Server 5 with NestJS. This causes missing graphql.resolve spans in distributed traces, making it impossible to see the performance of custom resolver logic.

Example: When executing a query like:

query getDepartment {
  department(id: "d009") {
    id
    name
    employees { items { id lastName firstName } }
  }
}

Expected spans for graphql.resolve department and graphql.resolve department.employees were completely missing—only scalar fields (id, name) generated spans.

Root cause: Apollo Server wraps resolvers after schema creation but before query execution. The old implementation used a permanent type-level "already patched" flag that skipped re-checking types, so late-added resolvers were never wrapped.

Short description of the changes

1. Per-query visited set instead of permanent type marking

   • Replace type-level OTEL_PATCHED_SYMBOL check with a temporary visitedInThisTraversal Set
   • Each query execution starts fresh, allowing detection of new resolvers Apollo may have added
   • Prevents infinite loops on circular type references (e.g., User → friends → User)

2. Per-resolver wrapping instead of per-type wrapping

   • Check if individual resolver functions are wrapped, not just the type
   • Allows newly attached resolvers to be wrapped on subsequent executes
   • Prevents double-wrapping with resolver-level idempotency check

3. Changes made

   • src/instrumentation.ts: Create and pass shared visited Set to wrapFields() calls
   • src/utils.ts: Update wrapFields() to use per-traversal Set; update wrapFieldResolver() to check resolver functions directly
   • src/utils.ts (wrapFieldResolver guard): check fieldResolver[OTEL_PATCHED_SYMBOL] (incoming resolver) instead of wrappedFieldResolver[OTEL_PATCHED_SYMBOL] (new wrapper being created)
   • src/utils.ts (wrapFieldResolver guard): keep typeof fieldResolver !== 'function' as the first condition so non-function/undefined resolvers return early before any symbol lookup

4. Verification

   • Previously missing resolver spans (for example graphql.resolve department and graphql.resolve department.employees) are now visible in traces
   • All existing package tests pass