homericintelligence/.claude-plugin/skills/backward-compat-removal

Skill: backward-compat-removal

Overview

| Field | Value | |-------|-------| | Date | 2026-02-20 | | Issue | #784 | | PR | #832 | | Objective | Remove deprecated BaseExecutionInfo dataclass as part of the target major version cleanup | | Outcome | Success — 209 lines deleted, 2266 tests pass, all pre-commit hooks green | | Category | testing |

When to Use

Trigger this skill when:

• A class or symbol has a DeprecationWarning added via warnings.warn()
• The deprecation milestone (e.g. the target major version) has arrived
• Issue says "delete", "remove", or "cleanup" for a previously deprecated symbol
• You see TestXxxBackwardCompatibility or TestXxx test classes only testing deprecated code

Verified Workflow

Phase 1 — Identify all references

grep -rn "BaseExecutionInfo" scylla/ tests/

Check for:

1. The class definition in scylla/core/results.py
2. The __init__.py export
3. Any import in test files
4. Docstring mentions in other modules (not imports, just text)

Phase 2 — Remove the class

In the source file (scylla/core/results.py):

• Delete the @dataclass decorator and entire class body
• Delete import warnings only if it becomes unused — check the whole file first
• Keep from dataclasses import dataclass if any other dataclass exists in the file
• Remove any module-level docstring line that references the deprecated class

Phase 3 — Remove the export

In scylla/core/__init__.py:

• Remove from the from scylla.core.results import (...) block
• Remove from __all__

Phase 4 — Delete test classes entirely

In tests/unit/core/test_results.py:

• Delete TestBaseExecutionInfo class entirely (all methods)
• Delete TestBaseExecutionInfoBackwardCompatibility class entirely
• Update the import line to remove the deleted symbol
• Remove any methods in other test classes (TestComposedTypes, etc.) that reference the deleted symbol
• Never leave test classes as @pytest.mark.skip — delete them outright

Phase 5 — Update docstring cross-references

Search for text-only mentions in docstrings:

grep -rn "BaseExecutionInfo" scylla/

Remove lines like - BaseExecutionInfo (core/results.py) - Legacy dataclass (deprecated) from docstring "see also" lists in other modules.

Phase 6 — Verify

pixi run python -m pytest tests/ -v
grep -rn "BaseExecutionInfo" scylla/ tests/   # should return empty
pre-commit run --all-files

Key Decisions

| Decision | Rationale | |----------|-----------| | Delete test classes, not skip | Skipped tests are dead weight; they will never be unskipped | | Keep @dataclass import if other dataclasses exist | BaseRunMetrics is also a @dataclass in results.py | | Scope: deletion only | No migration, no refactoring of other callers — those should already use the replacement | | Remove docstring mentions | Stale "see also" references mislead future readers |

Failed Attempts

None — the systematic 6-phase approach from the issue plan worked first time.

The only non-obvious step was checking whether import warnings could be removed (yes, it was only used by BaseExecutionInfo.__post_init__), and whether from dataclasses import dataclass could be removed (no — BaseRunMetrics is also a dataclass).

Results & Parameters

Files changed: 5
Lines deleted: 209
Lines added: 1
Tests: 2266 passed, 0 failed
Coverage: 73.57% (above 73% threshold)
Pre-commit hooks: all passed
Zero remaining references after cleanup