Port #3841 to 6.1: Introduce app context switch for setting MSF=true #3851
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
apoorvdeshmukh
force-pushed
the
dev/ad/port3841to61
branch
from
5572da6 to
99d6fa3
Compare
Contributor
There was a problem hiding this comment.
Pull request overview
This PR ports #3841 to the release/6.1 branch, introducing an app context switch (Switch.Microsoft.Data.SqlClient.EnableMultiSubnetFailoverByDefault) that allows applications to enable MultiSubnetFailover by default without explicitly setting it in each connection string. When the switch is set to true, MultiSubnetFailover defaults to true instead of false, enabling parallel IP connection attempts for improved connection times in multi-subnet environments.
Key changes:
- Added new app context switch
EnableMultiSubnetFailoverByDefaultwith tristate lazy initialization pattern - Changed
MultiSubnetFailoverdefault from const to static property to allow runtime evaluation based on the app context switch - Added comprehensive test coverage for the new switch behavior including unit and functional tests
Reviewed changes
Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.
Show a summary per file
| File | Description |
|---|---|
src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/LocalAppContextSwitches.cs |
Added EnableMultiSubnetFailoverByDefault property and backing field with tristate lazy initialization |
src/Microsoft.Data.SqlClient/src/Microsoft/Data/Common/ConnectionString/DbConnectionStringDefaults.cs |
Changed MultiSubnetFailover from const to static property that evaluates the app context switch |
src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/SqlConnectionString.cs |
Changed DEFAULT.MultiSubnetFailover from const to static property to support runtime evaluation |
src/Microsoft.Data.SqlClient/tests/Common/LocalAppContextSwitchesHelper.cs |
Added test helper infrastructure for manipulating and restoring the new switch value |
src/Microsoft.Data.SqlClient/tests/FunctionalTests/LocalAppContextSwitchesTests.cs |
Added test to verify the new switch defaults to false |
src/Microsoft.Data.SqlClient/tests/UnitTests/Microsoft/Data/SqlClient/SqlConnectionStringTest.cs |
Added parameterized test for MultiSubnetFailover behavior with various combinations of connection string values and app context switch states; includes commented-out test for FailoverPartner validation |
...Microsoft.Data.SqlClient/tests/UnitTests/Microsoft/Data/SqlClient/SqlConnectionStringTest.cs
Show resolved
Hide resolved
src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/LocalAppContextSwitches.cs
Show resolved
Hide resolved
Codecov Report❌ Patch coverage is
Additional details and impacted files@@ Coverage Diff @@
## release/6.1 #3851 +/- ##
===============================================
- Coverage 66.21% 64.30% -1.91%
===============================================
Files 279 279
Lines 53293 53301 +8
===============================================
- Hits 35286 34275 -1011
- Misses 18007 19026 +1019
Flags with carried forward coverage won't be shown. Click here to find out more. ☔ View full report in Codecov by Sentry. 🚀 New features to boost your workflow:
|
mdaigle
approved these changes
Dec 15, 2025
paulmedynski
approved these changes
Dec 15, 2025
This was referenced Jan 15, 2026
Open
This was referenced Jan 16, 2026
Open
Closed
Closed
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
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.
Ports #3841 to release branch 6.1
Issues
AB#41015
Guidelines
Please review the contribution guidelines before submitting a pull request: