Null header value results in page crash

[subhan-nadeem]

Describe the bug

In GraphQL Mesh, faced internal crashes where API responses were crashing due Access-Control-Allow-Origin header being set with nil value by response server:

 "message": "TypeError: Cannot read properties of undefined (reading 'includes')\n    at /Users/<user>/Desktop/<project>/graphqlmesh/node_modules/@whatwg-node/node-fetch/cjs/Headers.js:238:37\n    at /Users/<user>/Desktop/<project>/graphqlmesh/node_modules/@whatwg-node/node-fetch/cjs/Headers.js:149:25\n    at Array.forEach (<anonymous>)\n    at PonyfillHeaders.forEach (/Users/<user>/Desktop/<project>/graphqlmesh/node_modules/@whatwg-node/node-fetch/cjs/Headers.js:148:38)\n    at PonyfillHeaders.[nodejs.util.inspect.custom] (/Users/<user>/Desktop/<project>/graphqlmesh/node_modules/@whatwg-node/node-fetch/cjs/Headers.js:233:14)\n    at formatValue (node:internal/util/inspect:806:19)\n    at formatProperty (node:internal/util/inspect:1946:11)\n    at formatRaw (node:internal/util/inspect:1055:9)\n    at formatValue (node:internal/util/inspect:841:10)\n    at Object.inspect (node:internal/util/inspect:365:10)\nThis is caused by either a bug in Node.js or incorrect usage of Node.js internals.\nPlease open an issue with this stack trace at https://github.com/nodejs/node/issues\n",

Root cause seems to be the fact that the library does not guard against nil header values here: https://github.com/ardatan/whatwg-node/blob/master/packages/node-fetch/src/Headers.ts#L266

Should be an easy fix hopefully?

To Reproduce Steps to reproduce the behavior:

• Instantiate a mock server in GraphQL Mesh and set Access-Control-Allow-Origin to undefined/nil in response to a query

Environment:

• whatwg-node/fetch@0.9.16
• "@graphql-mesh/cli": "^0.88.6"

@ardatan

[ardatan]

Could you create a reproduction on CodeSandbox? Thanks! 🙏

[ardatan]

I'd love to help you and learn more about your use case of GraphQL Mesh. If you give more information at least, we can try to reproduce by ourselves. Thanks!