Resolving large specs takes very long / crashes

Q&A (please complete the following information)

• OS: Ubuntu 22.04
• Environment: Node 16.13.2
• Method of installation: npm
• Swagger-Client version: 3.18.5
• Swagger/OpenAPI version: OpenAPI 3.0

Content & configuration

Swagger/OpenAPI definition: Stripe

Swagger-Client usage:

const SwaggerClient = require('swagger-client');

SwaggerClient.resolve({url: 'https://github.com/stripe/openapi/raw/master/openapi/spec3.json'})

Describe the bug you're encountering

Running the above script takes very long and and uses one CPU core non-stop 100%. I was too impatient to wait until it might complete or node.js fails, so I cancelled the process after 27 minutes. A user of my downstream library reported that the process crashes after about one hour.

To reproduce...

Steps to reproduce the behavior:

1. Run the script above (e.g. node index.js)

Expected behavior

The script terminates successfully after a reasonable period of time.

Additional context or thoughts

While I think it is acceptable that resolving very large / complex specs takes longer, I would think that it should be faster than it is at the moment. Doing the same using the Java swagger-parser only takes a few seconds for the same spec.

Start by running the provided Node.js script against Stripe's OpenAPI definition and measure resolution time, CPU use, and whether the process crashes. Trace the SwaggerClient.resolve entry point to identify the resolution path responsible, then verify that the same reproduction completes in a reasonable time without sustained CPU exhaustion or a crash.