Development Environment Setup

This guide helps you set up the development environment for MygramDB with real-time linting and auto-formatting (like ESLint/Prettier for JavaScript).

Prerequisites

Before starting development, install the required tools.

macOS

# Install Homebrew (if not already installed)
/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"

# Install development tools
brew install cmake
brew install llvm@18  # Version 18 required for consistent formatting
brew install mysql-client@8.4
brew install icu4c

# Create symlinks to use LLVM 18 by default
# IMPORTANT: This ensures consistent code formatting with CI
ln -sf /opt/homebrew/opt/llvm@18/bin/clang-format /opt/homebrew/bin/clang-format
ln -sf /opt/homebrew/opt/llvm@18/bin/clang-tidy /opt/homebrew/bin/clang-tidy
ln -sf /opt/homebrew/opt/llvm@18/bin/clangd /opt/homebrew/bin/clangd

Linux (Ubuntu/Debian)

# Update package list
sudo apt-get update

# Install basic development tools
sudo apt-get install -y \
  cmake \
  build-essential \
  libmysqlclient-dev \
  libicu-dev \
  pkg-config \
  wget \
  lsb-release \
  software-properties-common \
  gnupg

# Install LLVM/Clang 18 (required for consistent formatting)
# IMPORTANT: Version 18 is required to match CI environment
wget https://apt.llvm.org/llvm.sh
chmod +x llvm.sh
sudo ./llvm.sh 18

# Install clang-format, clang-tidy, and clangd version 18
sudo apt-get install -y clang-format-18 clang-tidy-18 clangd-18

# Set version 18 as default
sudo update-alternatives --install /usr/bin/clang-format clang-format /usr/bin/clang-format-18 100
sudo update-alternatives --install /usr/bin/clang-tidy clang-tidy /usr/bin/clang-tidy-18 100
sudo update-alternatives --install /usr/bin/clangd clangd /usr/bin/clangd-18 100

Verify Installation

# Check if tools are installed
cmake --version        # Should show 3.15+
clang-format --version # Should show 18.x.x
clang-tidy --version   # Should show 18.x.x
clangd --version       # Should show 18.x.x (optional, for LSP)

Why version 18? Different versions of clang-format produce different formatting results. We standardize on version 18 to ensure consistency between local development and CI.

Build Project

# Build the project (generates compile_commands.json)
make

# Run tests
make test

# Format code
make format

After building, compile_commands.json will be generated in the build/ directory. This file is required for clangd and clang-tidy to work correctly.

VS Code Setup

Required Extensions

Open VS Code and install the recommended extensions:

1. C/C++ (ms-vscode.cpptools) - IntelliSense and debugging
2. CMake Tools (ms-vscode.cmake-tools) - CMake integration
3. Error Lens (usernamehw.errorlens) - Inline error display (like ESLint)

Optional Extension (for best experience)

4. clangd (llvm-vs-code-extensions.vscode-clangd) - Fast LSP for real-time linting

Enable Linting

After building the project, enable linting in VS Code:

Option A: Using C/C++ Extension (Simpler)

Edit .vscode/settings.json and change:

"C_Cpp.codeAnalysis.clangTidy.enabled": true,
"C_Cpp.codeAnalysis.clangTidy.useBuildPath": true,

Reload VS Code window (Cmd/Ctrl + Shift + P → "Developer: Reload Window")

Option B: Using clangd (Faster, ESLint-like experience)

1. Make sure clangd extension is installed
2. Edit .vscode/settings.json and uncomment the clangd section (OPTION 1)
3. Comment out the C/C++ Extension section (OPTION 2)
4. Reload VS Code window

Features Enabled

After setup, you'll have:

• Real-time linting - clang-tidy checks as you type
• Auto-formatting - Code formatted on save (Google C++ Style)
• Inline errors - Errors displayed inline with Error Lens
• Code completion - IntelliSense for C++17
• Quick fixes - Auto-fix available issues on save

Coding Standards

This project follows the Google C++ Style Guide with specific configurations:

Code Formatting

• Base style: Google
• Column limit: 120 characters
• Indentation: 2 spaces (no tabs)
• Pointer alignment: Left (int* ptr, not int *ptr)
• Braces: Attach style (if (x) {)

Run formatting tools:

make format        # Auto-format all code
make format-check  # Check formatting (CI mode - fails if not formatted)
make lint          # Run clang-tidy static analysis (takes time)

Naming Conventions

Element	Convention	Example
Classes	CamelCase	DocumentStore, Index
Functions	CamelCase	AddDocument(), GetPrimaryKey()
Variables	lower_case	doc_id, primary_key
Constants	kCamelCase	kMaxConnections, kDefaultPort
Member variables	lower_case_	next_doc_id_, term_postings_
Namespaces	lower_case	mygramdb::index

Documentation Comments

Use Doxygen-style comments for all public APIs:

/**
 * @brief Brief description of what the function does
 *
 * @param param_name Description of parameter
 * @return Description of return value
 */
ReturnType FunctionName(Type param_name);

Suppressing clang-tidy Warnings

When necessary, suppress warnings using NOLINT comments:

// Good: Use NOLINTNEXTLINE before the problematic line
// NOLINTNEXTLINE(cppcoreguidelines-pro-type-vararg)
snprintf(buf, sizeof(buf), "%d", value);

// Good: Inline NOLINT (keep comments within 120 chars)
char buf[32];  // NOLINT(cppcoreguidelines-avoid-c-arrays)

// Bad: Multi-line NOLINT (not recognized by clang-tidy)
snprintf(buf, sizeof(buf), "%d",
         value);  // NOLINT(cppcoreguidelines-pro-type-vararg)

// Good: File-level suppression for pervasive issues
// NOLINTBEGIN(cppcoreguidelines-pro-bounds-pointer-arithmetic)
// ... code requiring pointer arithmetic ...
// NOLINTEND(cppcoreguidelines-pro-bounds-pointer-arithmetic)

Important: NOLINT comments must be on a single line. Multi-line comments are not recognized.

Running Tests

Using Makefile:

make test

Or using CTest directly:

cd build
ctest --output-on-failure

Troubleshooting

"clangd: Unable to find compile_commands.json"

Solution: Run make to build the project first.

"clang-tidy: error while loading shared libraries"

Solution: Install clang-tidy version 18:

# macOS
brew install llvm@18
ln -sf /opt/homebrew/opt/llvm@18/bin/clang-tidy /opt/homebrew/bin/clang-tidy

# Linux
wget https://apt.llvm.org/llvm.sh
chmod +x llvm.sh
sudo ./llvm.sh 18
sudo apt-get install -y clang-tidy-18
sudo update-alternatives --install /usr/bin/clang-tidy clang-tidy /usr/bin/clang-tidy-18 100

"Many errors in VS Code after opening project"

Solution:

1. Make sure project is built: make
2. Check if build/compile_commands.json exists
3. Reload VS Code window: Cmd/Ctrl + Shift + P → "Developer: Reload Window"

"clang-format not working"

Solution: Install clang-format version 18:

# macOS
brew install llvm@18
ln -sf /opt/homebrew/opt/llvm@18/bin/clang-format /opt/homebrew/bin/clang-format

# Linux
wget https://apt.llvm.org/llvm.sh
chmod +x llvm.sh
sudo ./llvm.sh 18
sudo apt-get install -y clang-format-18
sudo update-alternatives --install /usr/bin/clang-format clang-format /usr/bin/clang-format-18 100

Verify the version:

clang-format --version  # Should show 18.x.x

Quick Start Checklist

• [ ] Install cmake
• [ ] Install LLVM 18 (clang-format-18, clang-tidy-18, clangd-18)
• [ ] Verify clang-format --version shows 18.x.x
• [ ] Install MySQL client library
• [ ] Install ICU library
• [ ] Run make to build project
• [ ] Verify build/compile_commands.json exists
• [ ] Install VS Code extensions (C/C++, CMake Tools, Error Lens)
• [ ] Enable clang-tidy in .vscode/settings.json
• [ ] Reload VS Code window

Next Steps

Once setup is complete:

1. Open any .cpp or .h file
2. Make a small change (e.g., add extra spaces)
3. Save the file → Auto-formatting should work
4. Try adding code that violates style guide → Should see warnings

Development Priorities

When implementing features or making changes, prioritize in this order:

1. Performance: Optimize for speed and low latency
2. Memory Efficiency: Minimize memory footprint
3. Maintainability: Write clean, testable code

Linux CI Testing (macOS Developers)

If you're developing on macOS, certain issues (missing headers, compiler differences) only appear in Linux environments and fail in CI.

Solution: Test your code in the same Linux environment used by GitHub Actions CI before pushing.

# Run full CI checks (recommended before git push)
make docker-ci-check

This runs:

1. Code formatting check
2. Build (with same flags as CI)
3. Clang-tidy linting
4. All tests

Individual checks:

make docker-build-linux       # Build only
make docker-test-linux        # Test only
make docker-lint-linux        # Lint only
make docker-format-check-linux # Format check only

Interactive shell:

make docker-dev-shell         # Enter Linux container for debugging

See Linux Testing Guide for details.

My Development Workflow (Optional Reference)

This is my personal workflow for maintaining code quality. You don't need to follow this exactly - the main requirement is that your PR passes CI checks.

What I typically do before committing:

1. Write code following Google C++ Style Guide
2. Run make format to auto-format code
3. Run make lint to catch issues early (slow, but worth it)
4. Run make test to ensure all tests pass
5. Run make docker-ci-check to verify Linux compatibility (macOS only)

CI Requirements

The following are automatically checked by CI:

• Code formatting (clang-format)
• Static analysis (clang-tidy)
• All tests pass
• No compiler warnings
• Linux build compatibility

You can rely on CI to check these if you prefer. Just make sure your PR passes all CI checks before merging.