[vistart]

Description

Adds SQL Server partition DDL and backend-level maintenance on the core partition plan/report contract.

SQL Server does not use PARTITION BY or PARTITION OF: a partitioned table is a partition function, a partition scheme and a table built ON <scheme>(<column>).

• Adds DDL expressions for CREATE PARTITION FUNCTION, CREATE PARTITION SCHEME, SPLIT RANGE, MERGE RANGE, NEXT USED, SWITCH PARTITION, and dropping the function or scheme.
• SQLServerPartitionPlan describes the function, boundaries, direction and optional scheme without embedding a table name or retention rule.
• SQLServerPartitionMaintenance and AsyncSQLServerPartitionMaintenance expose ensure, list, validate, retention_boundaries, drop_or_merge and drop_before.
• ensure creates missing functions and schemes and splits only boundaries the server does not already hold, emitting NEXT USED before each split; a direction or data-type mismatch raises instead of silently repairing.
• list reports functions, schemes, tables and per-partition ranges; validate only reports issues.
• drop_before computes boundaries at or before the caller's cutoff and merges them; there is no generic ADD/DROP PARTITION, and there is no subpartitioning at any version.
• Updates the README known-limitations section and adds syntax-matrix, unit and live tests.

No tracking issue.

Type of change

• feat: A new feature
• docs: Documentation only changes (if related to the new feature)
• test: Adding missing tests or correcting existing tests (for the new feature)
• perf: A code change that improves performance (if part of the feature)
• chore: Changes to the build process or auxiliary tools and libraries suchs as documentation generation (if related to the new feature)
• ci: Changes to our CI configuration files and scripts (if related to the new feature)
• build: Changes that affect the build system or external dependencies (if related to the new feature)
• revert: Reverts a previous commit

Breaking Change

• Yes, for end-users (backward-incompatible API changes)
• Yes, for backend developers (internal architectural changes that may affect custom implementations)
• No breaking changes

(If Yes, please describe the impact and migration path below):

N/A

Impact on End-Users:

No backward-incompatible changes are expected for typical end-user applications.

Impact on Backend Developers (Custom Implementations):

No backward-incompatible changes are expected for backend developers using custom implementations.

Applicable rhosocial-activerecord Version Range:

rhosocial-activerecord>=1.0.0.dev30,<2.0.0

Related Repositories/Packages

• Core: consumes the partition plan/report contract from core PR #130 (feature/partition-maintenance); this backend's test.yml installs core from that branch until PR #130 merges.
• No testsuite change is required; the existing suite is installed from release/v1.0.0.dev17.

Testing

• I have added new tests to cover my changes.
• I have updated existing tests to reflect my changes.
• All existing tests pass.
• This change has been tested on [specify backend/DB versions].

Test Plan:

Local full-suite execution was skipped per the merge workflow; the repository CI matrix will run:

pytest tests/rhosocial/activerecord_sqlserver_test/feature/backend/test_sqlserver_partition.py
pytest tests/rhosocial/activerecord_sqlserver_test/feature/backend/sqlserver/test_partition_syntax_matrix.py
pytest tests/rhosocial/activerecord_sqlserver_test/feature/backend/test_sqlserver_partition_live.py
pytest tests/rhosocial/activerecord_sqlserver_test/feature/backend/test_sqlserver_partition_maintenance.py

CI covers SQL Server 2017/2019/2022/2025 across Python 3.9–3.14.

Checklist

• My code follows the project's code style guidelines in .claude/code_style.md.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• I have made corresponding changes to the documentation (Docstrings, README.md, etc.).
• My changes generate no new warnings.
• I have added a Changelog fragment as described in .claude/version_control.md (changelog.d/<issue_number>.<type>.md).
• I have verified that my changes do not introduce SQL injection vulnerabilities.
• I have checked for potential performance regressions.

Additional Notes

The README conflict from the rebase was resolved by keeping the partition-maintenance capability description and removing the obsolete metadata-only limitation text. The changelog fragment is intentionally added after CI passes.

[sonarqubecloud]

Quality Gate passed

Issues
33 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
1.9% Duplication on New Code

See analysis details on SonarQube Cloud

[codecov]

Codecov Report

❌ Patch coverage is 75.27352% with 226 lines in your changes missing coverage. Please review.
✅ Project coverage is 78.67%. Comparing base (9c9a249) to head (cd93ccb).

Files with missing lines	Patch %	Lines
...rd/backend/impl/sqlserver/partition/maintenance.py	70.31%	103 Missing and 57 partials ⚠️
...ord/backend/impl/sqlserver/expression/partition.py	82.31%	18 Missing and 8 partials ⚠️
...iverecord/backend/impl/sqlserver/partition/plan.py	67.94%	17 Missing and 8 partials ⚠️
...erecord/backend/impl/sqlserver/partition/report.py	82.35%	3 Missing and 6 partials ⚠️
...cord/backend/impl/sqlserver/protocols/partition.py	53.84%	6 Missing ⚠️

Additional details and impacted files

@@                   Coverage Diff                   @@
##           release/v1.0.0.dev3      #13      +/-   ##
=======================================================
- Coverage                79.02%   78.67%   -0.36%     
=======================================================
  Files                      144      148       +4     
  Lines                     8893     9805     +912     
  Branches                  1364     1535     +171     
=======================================================
+ Hits                      7028     7714     +686     
- Misses                    1383     1530     +147     
- Partials                   482      561      +79     

Flag	Coverage Δ
python-3.14	78.67% <75.27%> (-0.36%)	⬇️
sqlserver-2025	78.67% <75.27%> (-0.36%)	⬇️
unittests	78.67% <75.27%> (-0.36%)	⬇️

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