migration-pattern-guard

---
name: migration-pattern-guard
version: 2.0.0
author: Abdox
description: |
  ULTRA-ADVANCED Migration Pattern Guard - Database migration validation - versioning, rollback, backward compat, expand-contract
  CAPABILITIES:
  - 8 anti-pattern detection patterns with severity scoring
  - Compliance scoring (A-F grade) with weighted severity model
  - Standards-based detection (Flyway practices; Expand-Migrate-Contract)
  - Automated fix suggestion generation
  - Directory scanning with aggregated reporting
  TRIGGER PHRASES: "migration check, schema migration, database versioning"
  STANDARDS: Flyway practices; Expand-Migrate-Contract
  ENVIRONMENT: Works with any codebase, any language, any framework.
  SECURITY: Read-only analysis.
---

# Migration Pattern Guard - ULTRA-ADVANCED v2.0

## Overview

Database migration validation - versioning, rollback, backward compat, expand-contract. This guard scans codebases for violations, scores compliance,
and generates actionable remediation recommendations.

## Detection Patterns

| Pattern | Description | Severity |
|---|---|---|
| Column rename/drop | Breaking change without compat | cr |
| No rollback script | Down migration missing | hi |
| Unversioned | No version identifier | hi |
| No checksum | Integrity unverified | md |
| Large migration | 1M+ rows affected | md |
| No staging test | Not tested on staging | hi |
| No repeatable | Seed data not versioned | lo |
| Business logic | Logic mixed with schema change | md |

## Standards

- Flyway practices; Expand-Migrate-Contract

## Scoring

| Grade | Score | Meaning |
|---|---|---|
| A | 90-100 | Excellent |
| B | 75-89 | Good |
| C | 60-74 | Fair |
| D | 40-59 | Poor |
| F | 0-39 | Failing |

## Implementation

```python
import re, os
from typing import Dict, List, Set, Any
from datetime import datetime

class MigrationPatternGuard:
    def __init__(self):
        self.file_results = {}
    def scan_file(self, fp: str) -> Dict:
        try:
            with open(fp, "r", encoding="utf-8", errors="ignore") as f:
                c = f.read()
            return self._analyze(c, fp)
        except Exception as e:
            return {"error": str(e), "file": fp}
    def _analyze(self, c: str, fp: str) -> Dict:
        issues = []
        for pid, info in self._patterns().items():
            m = re.findall(info["rx"], c, re.IGNORECASE | re.MULTILINE)
            if m:
                issues.append({"id": pid, "sev": info["sev"], "cnt": len(m), "msg": info["msg"]})
        s = max(0.0, 100.0 - sum(self._w(i["sev"]) * i["cnt"] for i in issues))
        return {"file": fp, "issues": issues, "score": round(s, 1), "grade": self._g(s), "at": datetime.now().isoformat()}
    def _patterns(self):
        return {}
    def _w(self, s):
        return {"cr": 10.0, "hi": 7.0, "md": 5.0, "lo": 2.0}.get(s, 5.0)
    def _g(self, s):
        return "A" if s >= 90 else "B" if s >= 75 else "C" if s >= 60 else "D" if s >= 40 else "F"
    def scan_dir(self, d, exts=None):
        r = {}
        sk = {".git", "node_modules", "venv", "__pycache__", "target", "build", "dist"}
        for root, dirs, files in os.walk(d):
            dirs[:] = [dd for dd in dirs if not dd.startswith(".") and dd not in sk]
            for f in files:
                if exts and not any(f.endswith(e) for e in exts): continue
                r[os.path.join(root, f)] = self.scan_file(os.path.join(root, f))
        return r
    def report(self, r):
        if not r: return {"error": "No results"}
        ti = sum(len(x.get("issues", [])) for x in r.values() if "issues" in x)
        sc = [x.get("score", 0) for x in r.values() if "score" in x]
        a = sum(sc) / len(sc) if sc else 0
        return {"files": len(r), "issues": ti, "avg": round(a, 1), "grade": self._g(a),
                 "cr": sum(1 for x in r.values() for i in x.get("issues", []) if i.get("sev") == "cr"),
                 "hi": sum(1 for x in r.values() for i in x.get("issues", []) if i.get("sev") == "hi"),
                 "recs": []}
```

---

**Version**: 2.0.0
**Status**: PRODUCTION READY
**Patterns**: 8
**Standards**: Flyway practices; Expand-Migrate-Contract

## See Also

- [code-migration](../../workflow/code-migration/SKILL.md)
- [data-migration](../../workflow/data-migration/SKILL.md)
- [database-migration-workflow](../../workflow/database-migration-workflow/SKILL.md)

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