Fix GraphQL Subscriptions Incorrectly Closing the Connection When Stream Returns an Error

[ThisaruGuruge]

Purpose

When a stream.next() function returns an error, GraphQL service should send an error response and then continue to work. But currently, this will cause to service to close the connection.

Fixes: #3565

Examples

N/A

Checklist

• Linked to an issue
• Updated the changelog
• Added tests
• Updated the spec
• Checked native-image compatibility

[codecov]

Codecov Report

Base: 87.16% // Head: 87.15% // Decreases project coverage by -0.00% ⚠️

Coverage data is based on head (1081cab) compared to base (0628cd2).
Patch coverage: 90.00% of modified lines in pull request are covered.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1014      +/-   ##
==========================================
- Coverage   87.16%   87.15%   -0.01%     
==========================================
  Files          59       59              
  Lines        4479     4485       +6     
  Branches     2443     2447       +4     
==========================================
+ Hits         3904     3909       +5     
- Misses        545      546       +1     
  Partials       30       30              

Impacted Files	Coverage Δ
ballerina/executor_visitor.bal	85.13% <0.00%> (ø)
ballerina/websocket_service.bal	88.15% <90.00%> (-4.38%)	⬇️
ballerina/engine.bal	97.53% <100.00%> (ø)
ballerina/field.bal	100.00% <100.00%> (ø)
ballerina/websocket_utils.bal	98.38% <100.00%> (+4.54%)	⬆️

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

☔ View full report at Codecov.
📢 Do you have feedback about the report comment? Let us know in this issue.