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Fix MultiSubnetFailover parallel connect when one address fails immediately - #4929
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Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
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🔵 Needs a closer look
Reported testing covers macOS, but platform-dependent socket behavior and cleanup still need Windows/Linux validation before approval.
No open issues 🎉
What changed in this PR
Fixes #4928 by allowing managed SNI parallel connections to continue when one address fails immediately, supporting the planned MultiSubnetFailover default change.
Changes:
- Records per-address socket failures and continues trying remaining addresses.
- Moves socket cleanup into
finallyto dispose non-selected sockets on normal and exceptional exits. - Exposes
ParallelConnectinternally and adds regression tests for mixed reachable/unreachable addresses and connection failure.
| File | Description |
|---|---|
| src/Microsoft.Data.SqlClient/tests/UnitTests/Microsoft/Data/SqlClient/ManagedSni/SniTcpHandleParallelConnectTests.cs | Adds mixed-address success and all-addresses-fail tests. |
| src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/ManagedSni/SniTcpHandle.netcore.cs | Handles immediate per-address failures and ensures socket cleanup. |
Review effort: Balanced
Codecov Report❌ Patch coverage is
Additional details and impacted files@@ Coverage Diff @@
## main #4929 +/- ##
==========================================
- Coverage 67.94% 66.15% -1.80%
==========================================
Files 311 305 -6
Lines 45399 68317 +22918
==========================================
+ Hits 30845 45193 +14348
- Misses 14554 23124 +8570
Flags with carried forward coverage won't be shown. Click here to find out more. ☔ View full report in Codecov by Harness. 🚀 New features to boost your workflow:
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priyankatiwari08
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Description
With
MultiSubnetFailover=true, managed SNIParallelConnectfailed the whole connection when one resolved address errored immediately (e.g. no IPv6 route), even if another address was reachable. Already-created sockets were also not disposed.SocketException, record it, and keep trying the remaining addresses.finallyblock.ParallelConnectinternalfor unit tests.Most of the diff is re-indentation; use
git diff -wto see the logic change (~40 lines).Issues
Fixes #4928. Related: #4876, #4927.
Testing
Passed, 30 tests (macOS, net10.0). The new good+bad address cases fail on the old code (3 failures) and pass with the fix.
git diff --check: passed. Windows/Linux not run locally.Guidelines
Please review the contribution guidelines before submitting a pull request: