Buglyst Blog
Learn to debug under pressure.
Playbooks for fast pattern recognition, guides for the full investigation, and articles for the engineering judgment around the edges.
17 playbooks · 509 guides · 95 articles · 12 linked practice labs ·skip to practice
Fast pattern recognition for the production failures engineers see most often.
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Structured investigations for the failure modes engineers meet in real systems.
Debugging GitHub Actions Cache Restore Miss: Why Your Actions Aren't Finding Cache
A practical guide to diagnosing and fixing cache restore misses in GitHub Actions workflows, covering key collisions, exact key matching, and non-obvious causes like branch scoping.
GitLab CI Pipeline Stuck in Pending: Debugging Runner Availability and Tag Mismatches
Diagnose why your GitLab CI pipeline stays pending. Covers runner registration, tag mismatches, concurrency limits, and queue backlogs.
Debugging Jenkins Pipeline Build Failures That Don't Show in Console Output
A practical guide to debugging Jenkins pipeline build failures that fail silently, with no obvious errors in the console log.
Pre-Commit Hook Failing: Debugging and Fixing Hook Execution Errors
A practical guide to diagnosing and resolving pre-commit hook failures in Git repositories, covering configuration, environment, and script issues.
ESLint Rule Conflict: How to Diagnose and Fix Competing Linter Directives
A complete guide to resolving ESLint rule conflicts where two or more rules produce contradictory outcomes, breaking your lint pipeline or CI.
semantic-release Not Creating a Release: Debugging the Silent Fail
A practical guide to debugging why semantic-release runs without errors but produces no release. Covers token issues, commit message parsing, and GitHub branch protection.
Long-form thinking on debugging habits, observability, and the systems around the bug.
How to Reproduce a Flaky Test: From CI Logs to Reliable Failure
A practical guide to turning intermittent test failures into reliably reproducible bugs, with techniques ranging from loop testing to thread sanitizers.
Property-Based Testing: Finding the Off-by-One That Lived in Production for 18 Months
A concrete story of how switching from example-based tests to property-based tests caught a timing bug that had survived code review, QA, and 18 months of production traffic.
How We Reduced End-to-End Test Flakiness by 80% with Deterministic Seeding
After months of chasing intermittent failures in our CI pipeline, we implemented a three-part strategy — deterministic seeding, isolated state per test, and a structured retry budget — that cut flaky end-to-end test failures by 80%.
Snapshot Testing: The 5 Hidden Failure Modes That Will Break Your CI
Snapshot tests seem like a safety net, but they often hide real bugs, bloat diffs, and silently break your CI. Here are the five failure modes I've seen in production and how to fix them.
Testing Async Code: Avoiding Flakiness and False Positives in JavaScript
Async testing is full of traps: unhandled rejections, race conditions, and tests that pass when they shouldn't. Here's how to write reliable async tests in JavaScript.
Testing Error Handling Code Paths: A Practical Approach
Error handling code is often the least tested and most brittle. Here's how to cover those paths with fault injection, mocks, and chaos engineering.