Ideas for additional labs

[tim-schilling]

Overview

Some ideas for additional labs based on common debugging scenarios Django developers face after completing the tutorial and working on their first projects.

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High Value (Almost everyone hits these)

Timezone Issues

• Naive vs aware datetime comparisons causing silent bugs
• USE_TZ=True but comparing with datetime.now() instead of timezone.now()
• Dates filtering incorrectly across timezone boundaries
• Great for Debug Toolbar since you can inspect the actual SQL datetime values

CSRF Token in AJAX Requests

• Form works fine, but JavaScript fetch/axios POST fails with 403
• Teaches browser dev tools Network panel for inspecting headers
• Common when adding interactivity to Django templates

Template Context Silently Failing

• Variable typo in template renders as empty string (no error)
• Missing context variable from view
• Teaches string_if_invalid setting and how Django's template silence can hide bugs

Migration Conflicts

• Two developers add migrations, both numbered 0005
• makemigrations --merge workflow
• Very common in team environments

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Medium Value (Common enough, good teaching moments)

Static Files Not Loading

• Works in development, breaks in production
• STATIC_URL vs STATIC_ROOT vs STATICFILES_DIRS confusion
• collectstatic not run
• Debug Toolbar can show 404s for static assets

Form Validation Errors Not Displaying

• form.errors exists but template doesn't render them
• {{ form.non_field_errors }} forgotten
• Field-level errors vs form-level errors

Middleware Ordering

• Authentication middleware after something that requires request.user
• Session middleware ordering issues
• Good for understanding the request/response cycle

Model.save() Not Persisting Changes

• Forgetting to call save() after modifying instance
• update_fields excluding the field you changed
• QuerySet methods returning new querysets (immutability confusion)

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Lower Priority (More niche but educational)

Email Not Sending in Development

• EMAIL_BACKEND not set to console backend
• Good excuse to introduce django-debug-toolbar's mail panel or django-mailer

Logging Configuration

• Logs not appearing despite logger.error() calls
• Log level hierarchy confusion
• Propagation issues