Four Migration Workers: Iterative Attempts at Fixing 281 Violations
The LEO root directory contained four successive migration worker scripts (`scratch_migration_worker.py` through `scratch_migration_worker_4.py`), each representing a separate attempt to programmatically migrate the 281 CMMU violation instances.
- Reference
- L021
- Project
- LEO
- Status
- Incomplete
- Evidence
- medium
- Source
- 021-scratch-migration-workers-iterative-attempts.md
Context
After the 281-violation Phase 28 audit report was generated, at least 4 attempts were made to write an automated migration tool that would transform direct database access code into CMMU-mediated access. These are scratch scripts preserved in the root directory of the project.
What Was Found
In the root directory (/home/ashish/Leo/):
scratch_migration_worker.pyscratch_migration_worker_2.pyscratch_migration_worker_3.pyscratch_migration_worker_4.py
In the backend directory (/home/ashish/Leo/backend/):
- Additional migration-related scratch files
The naming convention (scratch_ prefix) indicates these were experimental/exploratory scripts, not production tooling.
The presence of 4 successive iterations without completion indicates each attempt encountered problems that required a new approach.
Evidence
/home/ashish/Leo/scratch_migration_worker.py— first migration attempt/home/ashish/Leo/scratch_migration_worker_2.py— second iteration/home/ashish/Leo/scratch_migration_worker_3.py— third iteration/home/ashish/Leo/scratch_migration_worker_4.py— fourth iterationphase_28_x_2_violation_report.md— the migration target (281 violations to fix)
Diagnosis
Established: 4 successive migration scripts exist in the project root. The script names increment sequentially, indicating each was a separate iteration.
Likely: Each migration attempt encountered problems — possibly edge cases in the AST transformation, files that required manual handling, or changes that broke other tests. The scratch_ prefix indicates these were exploratory and not production-ready.
The challenge of automating a migration from Session() direct access to cmmu.begin_transaction() is non-trivial: it requires understanding the semantics of each database call, not just pattern-matching imports. Some calls may require context that a simple AST rewriter cannot infer.
Unknown: The content and specific failures of each iteration. Whether any of the 4 workers made partial progress (migrating a subset of violations). Why the 4th iteration was the last documented.
What I Learned
Automated migration of architectural violations is a class of problem where the difficulty scales non-linearly with semantic complexity. Simple pattern replacements (change import A to import B) can be done mechanically. Semantic migrations (change how database access is scoped and transacted) require understanding the call context, which AST-level tools often cannot provide reliably.
The 4-iteration pattern is common in exploratory migration tooling: each iteration handles more cases correctly but reveals new edge cases or complexity.
Broader Principle
When designing an architectural migration tool, expect multiple iterations. Start with the simplest transformation, measure coverage, identify the failure cases, and iterate. The 4 scratch scripts suggest an incremental approach was taken — a reasonable strategy for this complexity class.
Technical References
/home/ashish/Leo/scratch_migration_worker.py/home/ashish/Leo/scratch_migration_worker_2.py/home/ashish/Leo/scratch_migration_worker_3.py/home/ashish/Leo/scratch_migration_worker_4.pyphase_28_x_2_violation_report.md
Failure sequence
On the record- Attempt
- Failure
- Diagnosis
- **Established:** 4 successive migration scripts exist in the project root. The script names increment sequentially, indicating each was a separate iteration. **Likely:** Each migration attempt encountered problems — possibly edge cases in the AST transformation, files that required manual handling, or changes that broke other tests. The `scratch_` prefix indicates these were exploratory and not production-ready. The challenge of automating a migration from `Session()` direct access to `cmmu.begin_transaction()` is non-trivial: it requires understanding the semantics of each database call, not just pattern-matching imports. Some calls may require context that a simple AST rewriter cannot infer. **Unknown:** The content and specific failures of each iteration. Whether any of the 4 workers made partial progress (migrating a subset of violations). Why the 4th iteration was the last documented.
- Lesson
- Automated migration of architectural violations is a class of problem where the difficulty scales non-linearly with semantic complexity. Simple pattern replacements (change import A to import B) can be done mechanically. Semantic migrations (change how database access is scoped and transacted) require understanding the call context, which AST-level tools often cannot provide reliably. The 4-iteration pattern is common in exploratory migration tooling: each iteration handles more cases correctly but reveals new edge cases or complexity.
- Next iteration