VersionError invokes error middleware with null document on save()

[unc0ded]

Prerequisites

• I have written a descriptive issue title
• I have searched existing issues to ensure the issue has not already been raised

Issue

I am aware what causes the VersionError and also checked other issues where people reported a null value for the document in the error-handling middleware. My question is a combination of these, perhaps more of a general one: why does a VersionError on a .save() not make the document available in the middleware? Is it an intentional decision?

I have checked the source code here:

mongoose/lib/model.js

Line 535 in f3ab650

return callback(err);

Also went through other cases where the callback is invoked with the document and other places it's not. How is this determined? I have some code in an error-handling middleware which depends on the document being available, hence wanted to know what to expect.

[vkarpov15]

Fix will be in 8.16.1. In the meantime, you can do:

userSchema.post('save', function(err, doc, next) {
    // `this` contains the user doc even though `doc` is currently null
    next();
  });

[unc0ded]

Great! Thanks for the alternative solution, will try it out.