[DEP0174] DeprecationWarning: Calling promisify on a function that returns a Promise is likely a mistake.

[bcomnes]

Describe the bug

Node.js version: v21.7.1

OS version: macOS 14.4

Description: Started getting a node DeprecationWarning originating from line:

email-templates/index.js

Line 249 in e8b8cfc

const res = await util.promisify(renderFn)(filePath, locals);

Actual behavior

Test/usage output includes the following deprecation warnings.

(node:60785) [DEP0174] DeprecationWarning: Calling promisify on a function that returns a Promise is likely a mistake.
    at node:internal/util:431:17
    at new Promise (<anonymous>)
    at node:internal/util:416:12
    at Email.render (/Users/bret/Developer/email-templates/index.js:249:47)
    at async Promise.all (index 2)
    at Email.renderAll (/Users/bret/Developer/email-templates/index.js:263:37)
    at Email.send (/Users/bret/Developer/email-templates/index.js:333:20)
    at async /Users/bret/Developer/email-templates/test/test.js:233:9
(node:60785) [DEP0174] DeprecationWarning: Calling promisify on a function that returns a Promise is likely a mistake.
    at node:internal/util:431:17
    at new Promise (<anonymous>)
    at node:internal/util:416:12
    at Email.render (/Users/bret/Developer/email-templates/index.js:249:47)
    at async Promise.all (index 1)
    at Email.renderAll (/Users/bret/Developer/email-templates/index.js:263:37)
    at Email.send (/Users/bret/Developer/email-templates/index.js:333:20)
    at async /Users/bret/Developer/email-templates/test/test.js:233:9
  ✔ send two emails with two different locals

Expected behavior

It should avoid running promisify on promise returning functions.

  ✔ send two emails with two different locals

Code to reproduce

Run npm test running on node 21.

Checklist

• I have searched through GitHub issues for similar issues.
• I have completely read through the README and documentation.
• I have tested my code with the latest version of Node.js and this package and confirmed it is still not working.

[axelvugts]

Seeing the same behavior here, would be great if it could be looked into!

[ThuanLCSE]

Same issue in my product, please help to take a look.