motief/docs/solutions/best-practices/mindmodel-generation-anti-patterns.md

---
title: Critical Anti-Patterns Discovered During Mindmodel Generation
date: 2026-04-12
category: docs/solutions/best-practices
module: stemwijzer
problem_type: best_practice
component: documentation
severity: critical
applies_when:
  - When adding logging to any module
  - When working with Streamlit test isolation
  - When generating or updating .mindmodel/ for this project
tags: [anti-patterns, logging, streamlit, mindmodel, code-quality]
---

# Critical Anti-Patterns Discovered During Mindmodel Generation

## Context

During a comprehensive mindmodel generation session (Phase 1: 7 parallel analysis agents, Phase 2: constraint-writer assembly), several critical anti-patterns were discovered and documented in `.mindmodel/anti-patterns/anti-patterns.yaml`. This document captures the key findings for future reference.

## Guidance

### 1. Use Logging, Not Print Statements

**CRITICAL**: `api_client.py` uses `print()` instead of logging throughout (11 instances).

**Broken pattern:**
```python
# api_client.py - BAD
print(f"Fetched {len(voting_records)} voting records from API")
print(f"Error fetching motions from API: {e}")  # No traceback
```

**Correct pattern:**
```python
# GOOD - use logging throughout
import logging

_logger = logging.getLogger(__name__)

def get_motions(self, ...):
    try:
        _logger.info("Fetched %d voting records from API", len(voting_records))
    except Exception as e:
        _logger.exception("Error fetching motions from API: %s", e)
        return []
```

### 2. Streamlit Global State Replacement

**CRITICAL**: `explorer.py` has module-level `st = _DummySt()` which shadows Streamlit globally.

**Broken pattern:**
```python
# explorer.py - BAD
try:
    import plotly.express as px
except Exception:
    class _DummySt:
        figure = _DummyFigure
        # ...
    st = _DummySt()  # Global replacement - affects all imports!
```

**Correct pattern:**
```python
# GOOD - use conditional flags
try:
    import plotly.express as px
    import plotly.graph_objects as go
    HAS_PLOTLY = True
except ImportError:
    HAS_PLOTLY = False
    px = None
    go = None

def render_chart(data):
    if not HAS_PLOTLY:
        _logger.warning("Plotly not available")
        return
    # ... rest of chart logic
```

### 3. Logger Naming Inconsistency

**WARNING**: 33 files split between `logger = logging.getLogger(__name__)` and `_logger = logging.getLogger(__name__)`.

Files with `logger` (16): api_client.py, ai_provider.py, pipeline files, analysis files
Files with `_logger` (17): database.py, explorer.py, explorer_helpers.py

**Recommendation**: Standardize on `_logger` for module-level loggers. Update CODE_STYLE.md to explicitly state the convention.

### 4. Bare Except with Pass

**CRITICAL**: `database.py` line 47 has bare `except: pass` that catches KeyboardInterrupt, SystemExit, MemoryError.

**Broken pattern:**
```python
# database.py line 47 - BAD
try:
    conn.execute("CREATE SEQUENCE IF NOT EXISTS motions_id_seq START 1")
except:  # Catches EVERYTHING
    pass
```

**Correct pattern:**
```python
# GOOD
try:
    conn.execute("CREATE SEQUENCE IF NOT EXISTS motions_id_seq START 1")
except Exception as exc:
    _logger.debug("Sequence creation skipped: %s", exc)
```

## Why This Matters

1. **Logging over Print**: Structured logging enables log aggregation, filtering by level, and includes stack traces. Print statements are invisible in production and provide no context during failures.

2. **Global State**: Module-level replacements of standard library modules cause subtle bugs where code imports work differently depending on import order.

3. **Consistency**: Mixed logger naming makes code harder to grep and grep-replace. Pick one convention and enforce it via linting.

4. **Bare Except**: Catching all exceptions including `KeyboardInterrupt` and `SystemExit` can prevent graceful shutdown and mask serious issues.

## When to Apply

- Before committing any logging changes: ensure using `_logger`, not `print()`
- When adding optional dependency handling: use flags, not global replacements
- When updating CODE_STYLE.md: add explicit logger naming convention
- When updating .mindmodel/: verify anti-patterns section is current

## Examples

### Fixing api_client.py Logging

```python
# Before (broken)
print(f"Processed {count} motions")

# After (correct)
_logger.info("Processed %d motions", count)
```

### Fixing Exception Handling

```python
# Before (broken)
try:
    risky_operation()
except:
    pass

# After (correct)
try:
    risky_operation()
except Exception as exc:
    _logger.warning("Operation failed: %s", exc)
    return safe_fallback
```

## Related

- `.mindmodel/anti-patterns/anti-patterns.yaml` - Full anti-pattern documentation
- `.mindmodel/constraints/logging.yaml` - Logging conventions
- `.mindmodel/constraints/error-handling.yaml` - Error handling patterns
- `CODE_STYLE.md` - Code style guide (needs update for logger naming)
- `AGENTS.md` - Project conventions (RIGHT-wing parties on RIGHT, SVD labels = voting patterns)