Python 3.14

Overview of Python 3.14 Major Features

mindmap
  root((Python 3.14))
    Language & Syntax
      PEP 750: Template Strings (t-strings)
      PEP 649/749: Deferred Evaluation of Annotations
      PEP 758: Optional 
 Parentheses in `except`
      PEP 765: Control Flow Restrictions in `finally`
    Interpreter & Performance
      PEP 779: Free-threaded Python Officially Supported
      PEP 734: Multiple Interpreters in Standard Library
      New Opt-in Interpreter (tail calls)
      Improved Error Messages
      Incremental Garbage Collection
    Standard Library
      PEP 784: `compression.zstd` module
      Asyncio Introspection Capabilities
      Syntax Highlighting in REPL
      Color output in unittest, argparse, json
      UUID versions 6, 7, and 8
    Debugging & Tooling
      PEP 768: Safe External Debugger Interface
      pdb supports remote attaching
      PEP 741
    Release Changes
      PEP 761: PGP Signatures Discontinued
      Android Binary Releases
      Experimental JIT on Windows & macOS

Deferred Evaluation of Annotations (PEP 649 & PEP 749)

graph TD
    subgraph "Old Behavior (Python < 3.14)"
        direction TB
        A[Annotation is defined] --> B{Evaluation};
        B -- Eagerly at definition time --> C[May cause forward reference errors];
    end

    subgraph "New Behavior (Python 3.14)"
        direction TB
        D[Annotation is defined] --> E{Evaluation is deferred};
        E -- Stored as a string --> F[Evaluated only when needed by tools like type checkers];
        F --> G[Avoids forward reference issues];
    end

Multiple Interpreters in the Standard Library (PEP 734)

graph TD
    subgraph Process
        Main(Main Interpreter)
        MainGIL(GIL)

        Sub1(Interpreter 1)
        Sub1GIL(Own GIL)

        Sub2(Interpreter 2)
        Sub2GIL(Own GIL)

        Sub3(Interpreter 3)
        Sub3GIL(Own GIL)
    end

    subgraph Communication
        Shared((Shared Memory))
    end

    Main -- Manages --> Sub1
    Main -- Manages --> Sub2
    Main -- Manages --> Sub3

    Main --- MainGIL

    Sub1 --> Sub1GIL
    Sub2 --> Sub2GIL
    Sub3 --> Sub3GIL

    Sub1 -- Communicates via --> Shared
    Sub2 -- Communicates via --> Shared
    Sub3 -- Communicates via --> Shared

The Road to a GIL-less Python

gantt
    title The Path to Free-Threaded Python
    dateFormat  YYYY-MM-DD
    section Python Releases
    PEP 703 (Experimental) :milestone, 2024-10-01, 1d
    Python 3.13 Release    :active, 2024-10-01, 365d
    PEP 779 (Officially Supported) :milestone, 2025-10-07, 1d
    Python 3.14 Release    :crit, 2025-10-07, 365d

Enhanced Developer Experience

graph TD
    A[Developer Experience] --> B(REPL Improvements);
    A --> C(CLI Tooling);
    A --> D(Debugging);
    A --> E(Error Messages);

    B --> B1[Syntax Highlighting];
    B --> B2[Tab Completion for Imports];
    C --> C1[Colored output in `unittest`];
    C --> C2[Colored output in `argparse`];
    C --> C3[Colored output in `json` module];
    D --> D1[PEP 768: Zero-overhead debugger attachment];
    D --> D2[Remote debugging with `pdb`];
    E --> E1[More specific and helpful syntax error suggestions];

PEP: Python Enhancement Proposals

Sources:

• Python 3.14 Release Notes
• What’s new in Python 3.14