[release/6.0] Check BackgroundService.ExecuteTask for null #60177
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Backport of #60139 to release/6.0
/cc @eerhardt
Customer Impact
.NET 6.0 introduced an undocumented breaking change. IHostedService startup is now special-cased for BackgroundService, where the Host takes a direct dependency on BackgroundService.ExecuteTask, which can be null in some cases that previously worked. This was reported by a 1st party using 6.0 rc1.
The fix is a simple null check to avoid a NullReferenceException.
Testing
Added a new automated unit test for this scenario to ensure it works.
Risk
Very low.