CPython 3.15 Internals

Intro

Introduction to CPython

1. 1.1 What Is CPython?
2. 1.2 The Evolution to Version 3.15

Getting the CPython Source Code

1. 2.1 The CPython Repository
2. 2.2 Cloning the CPython 3.15 Source
3. 2.3 Compiling CPython 3.15 from Source
4. What’s next

Reading CPython Source Code Effectively

1. 3.1: Coding Conventions and Macro‑Heavy Patterns
2. 3.2: Navigating the Source Tree
3. 3.3: Tracing Object Lifecycles
4. 3.4: Debugging Crashes in CPython

The CPython Object Model

1. 4.1 Everything Is an Object
2. 4.2 Fundamental Data Types in Depth
3. 4.3 The Descriptor Protocol and Attribute Lookup

Memory Management

1. 5.1: The CPython Memory Allocator Stack
2. 5.2: Reference Counting – In Depth
3. 5.3: The Cyclic Garbage Collector (GC)

The Execution Model

1. 6.1 From Source Code to Bytecode
2. 6.2 The Frame and Execution Stack
3. 6.3 The Bytecode Interpreter
4. 6.4 The Two‑Tier Interpreter Architecture
5. 6.5 Calling Conventions and Vectorcall

The Global Interpreter Lock (GIL)

1. 7.1 What Is the GIL and Why Does It Exist?
2. 7.2 How the GIL Works in CPython 3.15
3. 7.3 The Free‑Threaded Build (No‑GIL)
4. 7.4 Connecting to the Previous Chapter
5. 7.5 Preview of the Next Chapter

Chapter 8: Subinterpreters and Isolated Execution

1. 8.1 What Are Subinterpreters?
2. 8.2 The PyInterpreterState and PyThreadState
3. 8.3 Interpreter State Isolation in 3.15

The JIT Compiler in CPython 3.15

1. 9.1 Introduction to Just‑In‑Time (JIT) Compilation
2. 9.2 How the JIT Works in 3.15
3. 9.3 JIT Performance in Practice

Bytecode and Optimization

1. 10.1 Python Bytecode in 3.15
2. 10.2 The Supercompiler and Adaptive Interpreter
3. 10.3 Performance Tuning

I/O and Performance Optimizations

1. 11.1 Faster I/O in CPython 3.15
2. 11.2 Asynchronous I/O and the Event Loop

The CPython Module System

1. 12.1: Built‑in Modules vs. Extension Modules
2. 12.2: The Import System Internals
3. 12.3: Loading and Initializing Extension Modules
4. 12.4: Lazy Imports (PEP 810)
5. End of Chapter 12

The C API

1. 13.1 The Three API Layers
2. 13.2 The abi3t Proposal
3. 13.3 Module Initialization
4. 13.4 Free‑Threading Compatibility
5. 13.5 What Does Not Change
6. 13.6 Vectorcall
7. 13.7 Writing an Extension for 3.15
8. 13.8 Testing
9. Summary

Embedding CPython

1. 14.1: Embedding Python in a C Application
2. 14.2: Subinterpreters in Embedded Environments
3. 14.3: WebAssembly and CPython 3.15

Security and SSL/TLS

1. 15.1: SSL/TLS Enhancements in 3.15
2. 15.2: Security Best Practices for Extensions

Debugging and Profiling CPython

1. 16.1 Debugging with GDB
2. 16.2 The New Statistical Profiler (PEP 799)
3. 16.3 Tracing and Instrumentation

The Build System and Cross‑Compilation

1. 17.1 The CPython Build System
2. 17.2 Cross‑Compiling CPython
3. Chapter Summary

CPython Contributor’s Workflow

1. 18.1: Setting Up a Development Environment
2. 18.2: Argument Clinic
3. 18.3: Testing CPython
4. 18.4: Continuous Integration and Buildbots
5. 18.5: Benchmarking and Performance
6. 18.6: Working with Generated Files