[BUG]: SpanOptions.tags doesn't handle nested objects

[Maxime-Reiz]

Tracer Version(s)

5.29.0

Node.js Version(s)

22.12.0

Bug Report

Issue Description

I want to create a trace in Datadog with nested business tags using the tags property of the SpanOptions in the tracer. While the tags documentation suggests we can provide any value (e.g., nested objects), my nested objects are not fully displayed in the span overview. Only up to two levels of nesting are visible.

// Tags documentation in SDK
export interface SpanOptions {
    /**
     * set of key-value pairs which will be set as tags on the newly created
     * Span. Ownership of the object is passed to the created span for
     * efficiency reasons (the caller should not modify this object after
     * calling startSpan).
     */
    tags?: { [key: string]: any };
}

Expected behaviour

The span overview in Datadog should display all levels of nested tags. For example:

// > Span > Overview > Span Attributes
{
   key1: value1,
   key2: value2,
   process: {
      priority: 'high',
      payload: {
         businessKey1: value1,
         businessKey2: value2,
         businessKey3: value3,
      }
   }
}

Actual behaviour

The span overview in Datadog only displays up to two levels of nesting:

// > Span > Overview > Span Attributes
{
   key1: value1,
   key2: value2,
   process: {
      priority: 'high',
   }
}

Code to reproduce

Current Code:

import tracer from 'dd-trace'

// [...]

const priority = 'high'
const payload = {
         businessKey1: value1,
         businessKey2: value2,
         businessKey3: value3,
      }
const process = { priority, payload }
return tracer.trace(
        'my-process-name',
        { tags: { process } },
        async () => {...}
)

Other attempt, working with one less level of nesting:

import tracer from 'dd-trace'

// [...]

const priority = 'high'
const payload = {
         businessKey1: value1,
         businessKey2: value2,
         businessKey3: value3,
      }
const process = { priority, payload }
return tracer.trace(
        'my-process-name',
        { tags: { ...process } },
        async () => {...}
)

Output of other attempt:

// > Span > Overview > Span Attributes
{
   key1: value1,
   key2: value2,
   priority: 'high',
   payload: {
      businessKey1: value1,
      businessKey2: value2,
      businessKey3: value3,
   }
}

Request

Can you clarify:

1. Is this behavior expected, or is it a bug in the SDK?
2. If expected, is there a recommended approach to include deeply nested tags in the span overview?

Thank you for your help!

Reproduction Code

No response

Error Logs

No response

Tracer Config

No response

Operating System

No response

Bundling

Webpack