| name | find-mismatch |
| effort | high |
| description | Systematic code review focusing on bugs that break at runtime (contract mismatches, logic/async errors, serialization, styling) and JS/TS static analysis via fallow.
|
| disable-model-invocation | true |
Find Mismatch
Walk through every file. Focus only on runtime failures/bugs. Do NOT report style, formatting, performance suggestions, docs/tests, or "consider using X".
1. Process
- JS/TS (Pre-check): Run static analysis.
- Check if installed:
fallow --version.
- Install globally if missing:
npm install -g fallow.
- Execute audit:
fallow audit --format json --quiet.
- Filter findings by git status:
git diff --staged --name-only.
- If staged: auto-apply safe fixes, re-run audit to verify.
- If unstaged: report-only (no modification).
- Review Checklist: Apply checklist to all changes.
- Report: Format findings using the specified template.
2. Checklist Categories
1. Cross-Boundary Contracts
- Calling mismatch: Check RPC, HTTP, IPC, event name/subject match receiver.
- Param names/types:
userId vs user_id, string vs number, flat vs wrapped.
- Return type: Field accesses (
result.field) must match return signature.
2. Serialization & Deserialization
- Casing:
snake_case in DB/backend vs camelCase in JSON/frontend.
- Optionals: Field expected by receiver but optional in producer.
- Enums/discriminators: Discriminant fields (
type, kind) and variants match.
- Base64: Double-encoding layers.
3. Logic Bugs
- Double counting: Counters incremented both in loop/branch and outside.
- Off-by-one: Index, pagination bounds (
page <= total vs page < total).
- Conditions: Redundant/dead flags, unreachable statements, shadowed variables.
4. Property & Method Access
- Null derefs: Method calls or array index access (
items[0].name) without null/length checks.
- Optional chaining: Stop check too early (e.g.
user?.address.street still crashes if address is null).
- This context: Callback bindings in classes.
5. Async & Concurrency
- Race conditions: Shared mutable states, parallel filesystem accesses without coordination.
- Missing
await: Promise ignored, silent errors.
- Leaks: File/DB/network connections not closed in error paths.
6. CSS & Styling
- HSL variables: Raw HSL components (
0 0% 100%) instead of functional format (hsl(0 0% 100%)) fail in Tailwind v4 (unlike v3).
- Inline themes: Circular references, selector mismatch (class vs data-theme).
7. Placeholder & Stub Code
- Unused declarations/files/dependencies, TODO comments, empty catch blocks.
3. Language-Specific Pitfalls
- Python: Hallucinated library methods (pandas, numpy, requests), sync/asyncio confusion, mutable default arguments (
def f(x=[])), silent indentation drops.
- JS/TS: Backend (Node) vs Frontend (Browser) API mix-ups,
any abuse, type-only import mismatches, barrel file false positives (exported but unused in production, used in tests/libraries).
- C++: Raw vs smart pointer mix-ups, missing standard library header
#include, uninitialized variables, buffer overflows.
- Rust: Borrow checker lifetime overcomplication,
unwrap() on None/Err, locking across .await yield points.
- Java / .NET: Hallucinated annotations/attributes, LINQ N+1 queries, Entity Framework model snapshot drift / missing migrations (check model changes under
Entities/ against Migrations/).
- Go: WaitGroup/Channel deadlocks, unexported struct fields in JSON, defer in loop, map concurrent access.
- PHP: Loose type comparisons (
== vs ===), array vs object access, key undefined.
4. Fallow Finding Mapping & Fixes
| Fallow Type | Checklist Category | Auto-Fix Action |
|---|
unused_exports | Placeholder & Stub | Remove export (if used locally) or entire declaration. |
unused_files | Placeholder & Stub | Delete file (check dynamic imports first). |
unused_dependencies | Placeholder & Stub | Remove dependency from package.json. |
circular_dependencies | Cross-Boundary | Defer to manual review (causes init bugs). |
complexity/duplication | Logic Bugs | Defer to manual review. |
5. Output Format
Include ## Review Summary header (only if JS/TS project):
## Review Summary
- **Manual review bugs found**: N
- **Fallow auto-fixed**: N findings (staged files only)
- **Fallow non-auto-fixable**: N findings
- **Fallow verdict**: pass / fail
Format individual findings (add [fallow] tag for fallow-sourced bugs):
## Bug #1
- **File**: <path>:<line>
- **Category**: <category>
- **What's wrong**: <description>
- **Runtime effect**: <effect>
- **Fix**: <code>
