Fixes & Debugging Guides

This category contains debugging guides and solutions for common programming errors and technical issues.

Each fix includes:

Problem description and error context
Root cause analysis
Step-by-step solution
Verification steps
Related troubleshooting tips

Fixes cover multiple programming languages, frameworks, development tools, dependency management, and environment configuration issues.

Fix: pip Install Permission Denied — User Installs and Virtualenv

Fix pip permission denied errors without using sudo. Covers --user installs, virtualenv, and why sudo pip is dangerous on macOS and Linux.

Fix: Python ModuleNotFoundError — Virtual Environments and Imports

Resolve Python ModuleNotFoundError by understanding virtual environments, PYTHONPATH, and dependency installation. Covers venv, pip, and IDE misconfiguration.

Fix: Sidekiq Jobs Not Processing — Troubleshooting Guide

Debug Sidekiq jobs that get enqueued but never process. Covers Redis connection, queue names, retry queues, and monitoring with the Sidekiq dashboard.

Fix: ActiveRecord::RecordNotFound — Safe Handling in Rails

Handle ActiveRecord::RecordNotFound errors gracefully in Rails. Covers find vs find_by, rescue strategies, custom error pages, and API responses.

Fix: PostgreSQL 'password authentication failed for user' Error

Resolve PostgreSQL password authentication failures. Covers pg_hba.conf, role passwords, Docker-specific issues, and local trust configuration.

Fixing PostgreSQL Connection Pool Exhaustion

How to diagnose and fix PostgreSQL connection pool exhaustion in production

Fix: PostgreSQL 'relation does not exist' Error

Solve the 'relation does not exist' error in PostgreSQL. Covers schema search paths, missing migrations, and case-sensitive naming.

Fix: PostgreSQL 'duplicate key violates unique constraint' Error

Resolve PostgreSQL duplicate key violation errors. Understand unique indexes, race conditions, UPSERT, and transaction isolation.

Fix: npm install fails with EACCES permission error

Quick fix for npm EACCES permission errors when installing packages globally on macOS and Linux systems.

Fix: PostgreSQL Data Not Persisting After Docker Container Restart

Prevent data loss when restarting PostgreSQL Docker containers. Covers volumes, bind mounts, named volumes, and how to verify persistence.

Fix: Docker Port Already Allocated — Resolving Port Conflicts

Fix 'port is already allocated' errors in Docker. Find conflicting processes, understand Docker networking, and resolve port conflicts quickly.

Fix: Docker Container Exits Immediately — Debugging and Solutions

Debug Docker containers that start and immediately exit. Covers ENTRYPOINT vs CMD, foreground processes, and log inspection techniques.

Fix: Git Permission Denied (publickey) — SSH Key Troubleshooting

Resolve the 'Permission denied (publickey)' error when pushing to GitHub. Covers SSH key generation, agent setup, and multiple key management.

Fix: Git Detached HEAD State — What It Means and How to Recover

Understand what a detached HEAD state in Git means, how to safely recover your work, and when it's actually useful.

Fix: How to Recover a Deleted Git Branch

Recover a deleted Git branch using reflog, dangling commits, and when recovery is impossible. Includes prevention tips.