Umbraco-CMS/docs/plans/2025-12-20-contentservice-refactor-phase0-implementation-summary.md

ContentService Refactoring Phase 0 Implementation Plan - Completion Summary

1. Overview

Original Scope and Goals: Phase 0 aimed to create test and benchmark infrastructure to establish baseline metrics and safety nets before the ContentService refactoring begins. The plan specified 12 tasks (Task 0-11), delivering 15 integration tests, 33 benchmarks, and 1 tracking unit test across 4 test files.

Overall Completion Status: Fully Completed (with post-completion fixes applied)

All planned tasks were executed, all test files were created, and baseline benchmarks were captured. A post-completion review identified and resolved 5 benchmark test implementation issues that were causing test failures.

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2. Completed Items

• Task 0: Committed ContentServiceBenchmarkBase.cs with warmup support for MeasureAndRecord methods
• Task 1: Created ContentServiceRefactoringTests.cs skeleton with notification handler infrastructure
• Task 2: Added 2 notification ordering tests for MoveToRecycleBin behavior
• Task 3: Added 3 sort operation tests (IContent, IDs, notifications)
• Task 4: Added 3 DeleteOfType tests (descendants, mixed types, multiple types)
• Task 5: Added 4 permission tests (SetPermission, multiple permissions, permission set, multiple groups)
• Task 6: Added 3 transaction boundary tests (rollback, commit, MoveToRecycleBin rollback)
• Task 7: Created ContentServiceRefactoringBenchmarks.cs with 33 benchmarks across 5 categories
• Task 8: Created ContentServiceBaseTests.cs with tracking test for Phase 1 detection
• Task 9: Verified all 15 integration tests pass
• Task 10: Captured baseline benchmarks to docs/plans/baseline-phase0.json
• Task 11: Created git tag phase-0-baseline and verified all artifacts

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3. Partially Completed or Modified Items

• Version-related benchmarks (GetVersions, GetVersionsSlim, Rollback, DeleteVersions): Required post-completion modification. The original implementation used Save() to create versions, but Umbraco's versioning system requires Publish() to create new versions. Tests were corrected to call Publish() after each Save().

• HasChildren benchmark: Required post-completion modification. The counter variable was accumulating across warmup and measurement runs due to the MeasureAndRecord warmup pattern. Fixed by resetting the counter inside the measurement action.

• Baseline JSON: Updated post-completion to reflect corrected benchmark values (33 entries now includes Rollback_ToVersion which was previously failing).

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4. Omitted or Deferred Items

None. All items from the original plan were implemented.

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5. Discrepancy Explanations

Item	Discrepancy	Explanation
Version benchmarks (4 tests)	Tests failed initially	Technical misunderstanding of Umbraco's versioning model. Save() updates the existing draft version; only Publish() creates a new version entry. The plan's comment "Create 100 versions by saving repeatedly" was incorrect.
HasChildren benchmark	Test failed with double-count	The MeasureAndRecord warmup pattern executes the action twice (warmup + measurement). Variables captured in closures retain their values across both runs, causing the counter to accumulate.
Baseline JSON values	5 entries differ from original capture	Original baseline captured incorrect values because the version tests were measuring single-version queries instead of 100-version queries. Corrected values reflect actual versioning behavior.
Rollback_ToVersion in baseline	Missing from original baseline	The test was failing during original baseline capture, so no JSON was emitted. Now included after fix.

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6. Key Achievements

• Comprehensive test coverage: 15 integration tests covering notification ordering, sort operations, DeleteOfType, permissions, and transaction boundaries provide robust safety nets for refactoring.

• Benchmark infrastructure: 33 benchmarks with JSON output enable automated regression detection across refactoring phases.

• Warmup pattern implementation: Benchmarks correctly handle JIT warmup for accurate measurements, with skipWarmup: true for destructive operations.

• Tracking test for Phase 1: The ContentServiceBase_WhenCreated_UncommentTests test will automatically detect when Phase 1 creates the ContentServiceBase class, prompting developers to activate the unit tests.

• Versioning behavior documentation: The fix process documented an important Umbraco behavior: Save() updates drafts, Publish() creates versions. This knowledge is now captured in code comments (v1.3 remarks).

• Git tag for baseline: The phase-0-baseline tag provides a clear rollback point and reference for future comparisons.

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7. Final Assessment

Phase 0 of the ContentService refactoring has been successfully completed. All planned test infrastructure is in place, with 15 integration tests validating behavioral contracts and 33 benchmarks establishing performance baselines. The post-completion fixes addressed implementation issues in 5 benchmark tests that stemmed from a misunderstanding of Umbraco's versioning model rather than issues with the ContentService itself.

The baseline JSON now contains accurate measurements for all 33 benchmarks, providing a reliable foundation for regression detection in subsequent refactoring phases. The tracking test ensures that unit tests for ContentServiceBase will be activated automatically when Phase 1 begins. The infrastructure is ready for Phase 1 implementation.