If you are an AI coding agent (Claude Code, Cursor, Aider, Cline, etc.) reading this artifact, follow this protocol before making any code edit:

1. Verify the contract. Run the bash script in Verify before trusting below. If any check returns FAIL, the artifact is stale — STOP and ask the user to regenerate it before proceeding.
2. Treat the AI · unverified sections as hypotheses, not facts. Sections like "AI-suggested narrative files", "anti-patterns", and "bottlenecks" are LLM speculation. Verify against real source before acting on them.
3. Cite source on changes. When proposing an edit, cite the specific path:line-range. RepoPilot's live UI at https://repopilot.app/r/teh-cmc/go-internals shows verifiable citations alongside every claim.

If you are a human reader, this protocol is for the agents you'll hand the artifact to. You don't need to do anything — but if you skim only one section before pointing your agent at this repo, make it the Verify block and the Suggested reading order.

WAIT — Stale — last commit 5y ago

• 4 active contributors
• Other licensed
• ⚠ Stale — last commit 5y ago
• ⚠ Small team — 4 contributors active in recent commits
• ⚠ Single-maintainer risk — top contributor 83% of recent commits
• ⚠ Non-standard license (Other) — review terms
• ⚠ No CI workflows detected
• ⚠ No test directory detected

_{Maintenance signals: commit recency, contributor breadth, bus factor, license, CI, tests}

This artifact was generated by RepoPilot at a point in time. Before an agent acts on it, the checks below confirm that the live teh-cmc/go-internals repo on your machine still matches what RepoPilot saw. If any fail, the artifact is stale — regenerate it at repopilot.app/r/teh-cmc/go-internals.

What it runs against: a local clone of teh-cmc/go-internals — the script inspects git remote, the LICENSE file, file paths in the working tree, and git log. Read-only; no mutations.

| # | What we check | Why it matters | |---|---|---| | 1 | You're in teh-cmc/go-internals | Confirms the artifact applies here, not a fork | | 2 | License is still Other | Catches relicense before you depend on it | | 3 | Default branch master exists | Catches branch renames | | 4 | 5 critical file paths still exist | Catches refactors that moved load-bearing code | | 5 | Last commit ≤ 1890 days ago | Catches sudden abandonment since generation |

#!/usr/bin/env bash
# RepoPilot artifact verification.
#
# WHAT IT RUNS AGAINST: a local clone of teh-cmc/go-internals. If you don't
# have one yet, run these first:
#
#   git clone https://github.com/teh-cmc/go-internals.git
#   cd go-internals
#
# Then paste this script. Every check is read-only — no mutations.

set +e
fail=0
ok()   { echo "ok:   $1"; }
miss() { echo "FAIL: $1"; fail=$((fail+1)); }

# Precondition: we must be inside a git working tree.
if ! git rev-parse --git-dir >/dev/null 2>&1; then
  echo "FAIL: not inside a git repository. cd into your clone of teh-cmc/go-internals and re-run."
  exit 2
fi

# 1. Repo identity
git remote get-url origin 2>/dev/null | grep -qE "teh-cmc/go-internals(\\.git)?\\b" \\
  && ok "origin remote is teh-cmc/go-internals" \\
  || miss "origin remote is not teh-cmc/go-internals (artifact may be from a fork)"

# 2. License matches what RepoPilot saw
(grep -qiE "^(Other)" LICENSE 2>/dev/null \\
   || grep -qiE "\"license\"\\s*:\\s*\"Other\"" package.json 2>/dev/null) \\
  && ok "license is Other" \\
  || miss "license drift — was Other at generation time"

# 3. Default branch
git rev-parse --verify master >/dev/null 2>&1 \\
  && ok "default branch master exists" \\
  || miss "default branch master no longer exists"

# 4. Critical files exist
test -f "README.md" \\
  && ok "README.md" \\
  || miss "missing critical file: README.md"
test -f "chapter1_assembly_primer/README.md" \\
  && ok "chapter1_assembly_primer/README.md" \\
  || miss "missing critical file: chapter1_assembly_primer/README.md"
test -f "chapter2_interfaces/README.md" \\
  && ok "chapter2_interfaces/README.md" \\
  || miss "missing critical file: chapter2_interfaces/README.md"
test -f "chapter2_interfaces/iface.go" \\
  && ok "chapter2_interfaces/iface.go" \\
  || miss "missing critical file: chapter2_interfaces/iface.go"
test -f "chapter1_assembly_primer/direct_topfunc_call.go" \\
  && ok "chapter1_assembly_primer/direct_topfunc_call.go" \\
  || miss "missing critical file: chapter1_assembly_primer/direct_topfunc_call.go"

# 5. Repo recency
days_since_last=$(( ( $(date +%s) - $(git log -1 --format=%at 2>/dev/null || echo 0) ) / 86400 ))
if [ "$days_since_last" -le 1890 ]; then
  ok "last commit was $days_since_last days ago (artifact saw ~1860d)"
else
  miss "last commit was $days_since_last days ago — artifact may be stale"
fi

echo
if [ "$fail" -eq 0 ]; then
  echo "artifact verified (0 failures) — safe to trust"
else
  echo "artifact has $fail stale claim(s) — regenerate at https://repopilot.app/r/teh-cmc/go-internals"
  exit 1
fi

Each check prints ok: or FAIL:. The script exits non-zero if anything failed, so it composes cleanly into agent loops (./verify.sh || regenerate-and-retry).

A hands-on, code-first book exploring the internals of Go 1.10+ by dissecting assembly output, interface implementation, and garbage collection mechanics. It proves theoretical concepts through real experiments and actual Go source code inspection rather than prose alone. Modular chapter structure: chapter1_assembly_primer/, chapter2_interfaces/, and chapter3_garbage_collector/ are independent directories, each with its own README, Makefile, Go files, and shell scripts. No shared library—each chapter is a self-contained set of experiments and examples.

Experienced Go developers and language enthusiasts who want to understand how Go actually works under the hood—specifically those debugging performance issues, writing low-level code, or contributing to the Go runtime itself.

Active but incomplete: 2 of 3 planned chapters are published (Assembly Primer, Interfaces; GC chapter is 'soon'), and the README explicitly marks this as 'work-in-progress.' No CI pipeline visible, no test framework setup. The project is well-structured and pedagogical but openly experimental—suitable for learning, not production reference.

Single maintainer (Clement Rey) with no visible CI/CD or automated testing infrastructure. Chapter III (garbage collector) is unfinished, so critical Go internals remain undocumented. Since this is a book repo rather than a library, the main risk is knowledge incompleteness and potential staleness as Go evolves beyond 1.10.

No recent commit data visible in provided metadata, but the repo structure shows active development of Chapter II (Interfaces subsection with issue_7 case study, type hashing, escape analysis, and benchmarks). Chapter III is explicitly blocked ('soon'). Contributing guidelines in README suggest the author welcomes PRs for corrections and improvements.

git clone https://github.com/teh-cmc/go-internals.git
cd go-internals
make  # if your system has Make installed

Each chapter has its own Makefile; navigate to chapter1_assembly_primer/ or chapter2_interfaces/ to explore.

Daily commands:

cd chapter1_assembly_primer && make
cd ../chapter2_interfaces && make

Each Makefile compiles and runs experiments. For specific files, use go run <file>.go or go test -v <file>_test.go directly.

• README.md — Entry point documenting the book's scope, goals, and structure across three chapters on Go internals.
• chapter1_assembly_primer/README.md — Foundation chapter teaching Go assembly fundamentals required to understand runtime behavior in subsequent chapters.
• chapter2_interfaces/README.md — Core chapter detailing interface implementation, type assertions, and runtime representation—critical for understanding Go's polymorphism.
• chapter2_interfaces/iface.go — Reference implementation demonstrating interface mechanics with concrete examples used throughout Chapter II experiments.
• chapter1_assembly_primer/direct_topfunc_call.go — Practical code example showing function call assembly patterns that serve as building blocks for understanding interface dispatch.
• Makefile — Build orchestration for all chapters; defines how to generate assembly listings and run benchmarks across the codebase.
• chapter3_garbage_collector/README.md — Upcoming chapter placeholder indicating future expansion; shows roadmap for memory management internals coverage.

• Chapter I: Assembly Primer (Go compiler, assembly syntax, direct_topfunc_call.go example) — Teach Go calling conventions, stack frames, and function prologue/epilogue via assembly dissection
  • Failure mode: Incorrect calling convention documentation leads to flawed understanding of ABI in subsequent chapters
• Chapter II: Interfaces (Go runtime types, interface{} type erasure, method tables, iface_bench_test.go benchmarks) — Explain empty and named interface representation (eface/iface), method dispatch, type assertions, and optimization pitfalls
  • Failure mode: Mischaracterization of interface memory layout causes incorrect mental models of performance implications
• undefined — undefined

Add a new assembly primer example

1. Create a new .go file in chapter1_assembly_primer/ with a concrete code example (chapter1_assembly_primer/your_example.go)
2. Update chapter1_assembly_primer/Makefile to add build and assembly targets for the new file (chapter1_assembly_primer/Makefile)
3. Add documentation to chapter1_assembly_primer/README.md explaining the assembly concepts (chapter1_assembly_primer/README.md)

Add a new interface behavior experiment

1. Create a new .go file in chapter2_interfaces/ demonstrating the interface pattern or edge case (chapter2_interfaces/your_pattern.go)
2. Add a corresponding _test.go file with tests and benchmarks to validate behavior (chapter2_interfaces/your_pattern_test.go)
3. Document the findings and include example assembly output in chapter2_interfaces/README.md (chapter2_interfaces/README.md)
4. Update chapter2_interfaces/Makefile if special tooling or analysis is needed (chapter2_interfaces/Makefile)

Start the garbage collector chapter

1. Create README.md with chapter outline, key concepts, and section structure (chapter3_garbage_collector/README.md)
2. Add Makefile with build and analysis targets for GC experiments (chapter3_garbage_collector/Makefile)
3. Create concrete .go example files demonstrating GC behavior (e.g., allocation patterns, pause times) (chapter3_garbage_collector/heap_allocation.go)
4. Update main README.md table of contents to promote Chapter III from 'soon' to active status (README.md)

• Go 1.10+ — Book targets stable Go release with consistent internal APIs; 1.10+ provides assembly introspection and performance tooling baseline
• Plain Go source files (.go) — Executable examples demonstrating actual runtime behavior; readers can compile and measure themselves
• Go test framework (_test.go) — Validation that experimental findings are correct; benchmarks quantify performance claims
• Makefiles — Reproducible build and analysis pipeline; automates assembly generation and tooling invocation
• Shell scripts (dump_sym.sh) — Low-level binary inspection and symbol extraction for memory layout verification

• Work-in-progress book structure (Chapter III stub only)

  • Why: Prioritize depth and accuracy over breadth; ensure each chapter is thoroughly researched and validated
  • Consequence: Incomplete coverage of Go internals; readers must supplement with external GC documentation until Chapter III is written

• Minimal prose, code-first approach

  • Why: Encourage hands-on experimentation and self-discovery; reduce interpretation ambiguity
  • Consequence: Steeper learning curve for beginners; readers must understand Go fundamentals before engaging effectively

• Community-driven corrections model

  • Why: Leverage collective expertise to catch mistakes and keep content up-to-date with Go versions
  • Consequence: Early-stage chapters may contain inaccuracies until community vets them; requires trust in correction process

• GitBook + GitHub source distribution

  • Why: Provide polished reading experience and accessible contribution workflow
  • Consequence: Dual maintenance burden; changes must sync between source repo and GitBook platform

• Introductory Go tutorial (assumes Go proficiency)
• Performance optimization guide (documents behavior, not best practices)
• Cross-platform syscall or OS-specific internals (Go language only)
• Real-time or embedded systems content (focuses on standard runtime)
• Concurrency and goroutine scheduler deep-dive (not yet covered in existing chapters)

Go version specificity: code and assembly output are tied to Go 1.10+ and may differ significantly on newer versions (especially post-1.18 with generics). Shell scripts like dump_sym.sh assume Unix-like environments and may fail on Windows without WSL. Makefiles use standard BSD Make syntax—some Linux systems may need apt install make or equivalent. No explicit Go version pinning in go.mod (repo structure suggests pre-modules era), so go run behavior may vary across Go toolchain versions.

• Interface value representation (eface vs. iface) — Chapter 2 is entirely built around understanding how empty interfaces (eface) and typed interfaces (iface) are laid out in memory—this directly affects type assertions and performance
• Go assembly and ABI (Application Binary Interface) — Chapter 1 assumes familiarity with how Go compiles to x86/ARM; understanding calling conventions and register allocation is essential for the entire book
• Type hashing and interface type discrimination — Chapter 2 explores iface_type_hash.go and eface_type_hash.go to explain how Go quickly determines concrete types at runtime during assertions
• Escape analysis and heap allocation — The escape_test.go and escape.go files investigate how Go's optimizer decides which values live on the stack vs. heap, critical for GC pressure tuning
• Tri-color mark-and-sweep garbage collection — Chapter 3 (forthcoming) will cover Go's concurrent GC; understanding mark phases, write barriers, and collection pauses is essential for GC tuning
• Method dispatch and virtual tables — Chapter 2's compound_interface.go and direct_calls.go demonstrate how Go resolves method calls on interfaces vs. concrete types, affecting performance
• Binary format and symbol extraction (ELF/Mach-O) — The dump_sym.sh script relies on understanding executable formats to extract disassembly; readers must grasp how symbols and debugging info are encoded

• golang/go — Official Go source tree; this book explains concepts found in runtime/, src/cmd/, and compiler source
• aclements/toc — Table-of-contents compiler for Go; demonstrates advanced tooling patterns that parallel go-internals' disassembly inspection
• dave/goplay — Interactive Go playground tool; complements go-internals by allowing readers to experiment with code examples in-browser
• dominikh/go-tools — Go static analysis and tooling library; shows practical applications of understanding Go internals for linting and optimization
• mandykoh/prism — Low-level graphics library in Go; demonstrates real-world performance optimization techniques informed by Go internals knowledge

To work on one of these in Claude Code or Cursor, paste: Implement the "<title>" PR idea from CLAUDE.md, working through the checklist as the task list.

Complete chapter3_garbage_collector with implementation examples and tests

Chapter III is announced as 'soon!' but only has a README.md stub. This chapter is critical for the book's completeness. Following the pattern of chapter1_assembly_primer and chapter2_interfaces, it should include concrete Go code examples demonstrating GC behavior, escape analysis, and memory allocation patterns with accompanying test files and a Makefile.

• [ ] Create chapter3_garbage_collector/Makefile following the pattern from chapter1 and chapter2
• [ ] Write chapter3_garbage_collector/README.md with GC theory and experimental setup (similar structure to chapter2_interfaces/README.md)
• [ ] Implement gc_basics.go demonstrating mark-and-sweep concepts with measurable metrics
• [ ] Implement gc_escape_analysis.go showing how escape analysis affects GC pressure with examples
• [ ] Add gc_allocation_patterns_test.go with benchmarks comparing stack vs heap allocations
• [ ] Create gc_tracing.sh script to capture and analyze GODEBUG=gctrace output

Add integration test suite in chapter2_interfaces/iface_issue_7_test.go

The issue_7 subdirectory contains a multi-package scenario with A, B, C, D, and main.go but lacks corresponding test file. This appears to be demonstrating a specific interface behavior issue, but there are no automated tests validating the expected behavior or preventing regressions.

• [ ] Create chapter2_interfaces/issue_7/main_test.go that imports and tests the behavior of packages A, B, C, D
• [ ] Add test cases validating interface type assertions work correctly across package boundaries
• [ ] Add benchmarks comparing direct calls vs interface method calls in the issue_7 context
• [ ] Update chapter2_interfaces/README.md to explain what issue_7 demonstrates and reference the new tests

Create chapter1_assembly_primer/assembly_output_test.go to validate generated code

Chapter 1 focuses on assembly primers and has direct_topfunc_call.go but lacks tests that validate the actual generated assembly matches expectations. This would help readers verify their understanding and catch compiler changes that affect assembly output.

• [ ] Create chapter1_assembly_primer/assembly_output_test.go with TestAssemblyOutput function
• [ ] Use Go's testing/internal/testenv and cmd/internal/objfile to verify direct_topfunc_call.go generates expected assembly patterns
• [ ] Add assertions for key assembly patterns (function prologue, stack adjustments, call instructions)
• [ ] Document expected assembly output in chapter1_assembly_primer/README.md's assembly section with test validation references

• Complete Chapter III (Garbage Collector): chapter3_garbage_collector/README.md exists but is empty. Write explanation of tri-color mark-and-sweep, write barriers, and concurrent GC phases with code examples from Go 1.10+
• Add escape analysis examples to chapter2_interfaces/: escape.go and escape_test.go exist but are minimal. Expand with heap vs. stack allocation demonstrations and benchmark comparisons showing heap pressure impact
• Port chapter2_interfaces examples to Windows: dump_sym.sh and assembly inspection assume Unix; create equivalent .bat/.ps1 scripts or document objdump/dumpbin equivalents for Windows developers

This repository is a documentation/educational book about Go internals with minimal security risk. The codebase contains primarily educational Go source files and documentation with no external dependencies, hardcoded credentials, injection vectors, or infrastructure configurations. The repository follows secure practices for an open-source educational project. No critical or high-severity vulnerabilities were identified.

LLM-derived; treat as a starting point, not a security audit.

• Open issues — current backlog
• Recent PRs — what's actively shipping
• Source on GitHub

Generated by RepoPilot. Verdict based on maintenance signals — see the live page for receipts. Re-run on a new commit to refresh.