Cannot read properties of undefined (reading 'push') when calling segment.close(error)

[foxxor]

Error trace

Cannot read properties of undefined (reading 'push')","stack":["TypeError: Cannot read properties of undefined (reading 'push')","    at Segment.addError (/app/node_modules/aws-xray-sdk-core/dist/lib/segments/segment.js:253:27)","    at Segment.close (/app/node_modules/aws-xray-sdk-core/dist/lib/segments/segment.js:316:14)

Steps to reproduce

I got this error under the specific scenario:

1. Create a segment, create a subsegment inside that parent segment.
2. Call subsegment.addError(err) with an error.
3. Afterwards in the main parent segment, call segment.close(err) with the same error.
4. Library throws the error specified above.

Code snippet

On /packages/core/lib/segments/segment.js

Segment.prototype.addError = function addError(err, remote) {
    if (err == null || typeof err !== 'object' && typeof (err) !== 'string') {
        logger.getLogger().error('Failed to add error:' + err + ' to subsegment "' + this.name +
            '".  Not an object or string literal.');
        return;
    }
    this.addFaultFlag();
    if (this.exception) {
        if (err === this.exception.ex) {
            this.cause = { id: this.exception.cause };
            delete this.exception;
            return;
        }
        delete this.exception;
    }
    if (this.cause === undefined) {
        this.cause = {
            working_directory: process.cwd(),
            exceptions: []
        };
    }
    this.cause.exceptions.push(new CapturedException(err, remote));
};

I think the error here is because the subsegment is setting its parent exception when subsegment.addError is called.

Then when trying to close the parent segment with the same error, it overwrites the cause with a new cause object that do not contain the exceptions array. So on line 311 of /packages/core/lib/segments/segment.js the call to push fails, because there's no array.

I think this can be fixed in the same way the other issue was resolved.

this.cause = { 
    id: this.exception.cause,
    exceptions: [] // Also initialize the array to prevent error on `this.exceptions.push(...)`
};

Related issues

I found a somewhat similar issue, that affected the subsegment.addError logic, created some time ago:

• Cannot read property 'unshift' of undefined #448