feat: add error message parameter to onError callback in subscription

[cromoteca]

Closes #2062.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.57%. Comparing base (50822ec) to head (0322682).
Report is 7 commits behind head on main.

Additional details and impacted files

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  Coverage   92.57%   92.57%           
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  Files          85       85           
  Lines        3166     3166           
  Branches      776      776           
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  Hits         2931     2931           
  Misses        183      183           
  Partials       52       52           

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unittests	92.57% <100.00%> (ø)

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[taefi]

Generally, this is a nice enhancement, but, isn't it automatically expose some unwanted error messages to the client as well? For instance, when an endpoint method returning a Signal is annotated with @RolesAllowed("ADMIN"), so far, the only thing on client was: "Error in flux ...", and I wonder if this change exposes the the "access denied" error message to the client, and cause a security issue.

[taefi]

Just adding this to block merging before the above question is answered.

[cromoteca]

Generally, this is a nice enhancement, but, isn't it automatically expose some unwanted error messages to the client as well? For instance, when an endpoint method returning a Signal is annotated with @RolesAllowed("ADMIN"), so far, the only thing on client was: "Error in flux ...", and I wonder if this change exposes the the "access denied" error message to the client, and cause a security issue.

The messages we're talking about here are already on the client. Without a callback, an error is thrown with the contents of the message. With a callback, the message was lost.

If the message contents are an issue on their own, I think that a separate issue should be opened.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[vaadin-bot]

This ticket/PR has been released with Hilla 24.7.0.alpha3 and is also targeting the upcoming stable 24.7.0 version.