From ed0a4766c19ace2482fa418a56b64aefca7aad04 Mon Sep 17 00:00:00 2001
From: Kush Rustagi <kush12360@gmail.com>
Date: Thu, 8 Jan 2026 18:39:43 +0530
Subject: [PATCH] yolo

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+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Build and Development Commands
+
+**Install dependencies:**
+```bash
+pip install -e ".[all]"
+pip install -r requirements-tests.txt
+```
+
+**Run tests:**
+```bash
+# Run all tests with coverage
+./scripts/test.sh
+
+# Run a single test file
+coverage run -m pytest tests/test_application.py
+
+# Run a specific test
+coverage run -m pytest tests/test_application.py::test_app -v
+
+# Note: PYTHONPATH=./docs_src is set by the test script for importing tutorial examples
+```
+
+**Linting and formatting:**
+```bash
+# Check linting (mypy + ruff)
+./scripts/lint.sh
+
+# Auto-fix and format
+./scripts/format.sh
+
+# Individual commands
+mypy fastapi
+ruff check fastapi tests docs_src scripts
+ruff format fastapi tests
+```
+
+**Pre-commit hooks:** Uses `uv run` for ruff and docs generation hooks.
+
+## Architecture Overview
+
+FastAPI is built on top of **Starlette** (ASGI framework) and **Pydantic** (data validation).
+
+### Core Module Structure (`fastapi/`)
+
+- **`applications.py`** - `FastAPI` class extending Starlette's `Starlette` class. Contains app initialization, OpenAPI schema generation, and route registration methods (`get`, `post`, `put`, etc.)
+
+- **`routing.py`** - `APIRouter` and `APIRoute` classes. Handles path operation decoration, request/response processing, and dependency injection integration. The `request_response` function wraps endpoints with `AsyncExitStack` for dependency lifecycle management.
+
+- **`params.py`** - Parameter classes (`Query`, `Path`, `Header`, `Cookie`, `Body`, `Form`, `File`) extending Pydantic's `FieldInfo`. These define how request data is extracted and validated.
+
+- **`param_functions.py`** - Function versions of parameter classes for use with `Annotated` typing pattern.
+
+- **`dependencies/`** - Dependency injection system:
+  - `models.py` - `Dependant` dataclass representing resolved dependency tree
+  - `utils.py` - `get_dependant()` analyzes function signatures, `solve_dependencies()` resolves and caches dependencies at request time
+
+- **`openapi/`** - OpenAPI/Swagger generation:
+  - `utils.py` - `get_openapi()` generates OpenAPI schema from routes
+  - `docs.py` - Swagger UI and ReDoc HTML generation
+  - `models.py` - Pydantic models for OpenAPI spec
+
+- **`security/`** - Security scheme implementations (OAuth2, API Key, HTTP Basic/Bearer)
+
+- **`_compat/`** - Pydantic v2 compatibility layer
+
+### Request Flow
+
+1. Request hits `FastAPI` app (Starlette ASGI)
+2. `APIRoute.handle()` matches route and calls endpoint wrapper
+3. `solve_dependencies()` resolves dependency tree (with caching)
+4. Parameters extracted from path/query/headers/body via `Param` classes
+5. Pydantic validates all inputs
+6. Endpoint function called with resolved dependencies
+7. Response serialized through `jsonable_encoder`
+
+### Testing Patterns
+
+Tests use `TestClient` from Starlette (via `fastapi.testclient`). Test files in `tests/` mirror the structure of tutorials in `docs_src/`. Tests import example code from `docs_src/` to verify documentation examples work correctly.