Make littlefs an optional dependency.

This change makes the `littlefs-python` package an optional dependency
for the `fs` command in the `mp-image-tool-esp32` package. This is
achieved by moving the `littlefs-python` package from the `dependencies`
section to the `project.optional-dependencies` section in the
`pyproject.toml` file. The `littlefs` extra is now required to install
the `littlefs-python` package.

pyproject.toml:
- move the `littlefs-python` package to the
  `project.optional-dependencies` section.
- use dependency_groups for the test and typing environments.
- Remove dependencies from the tox configuration and use the
  test dependency_group instead.

Author: glenn20

README.md

@@ -141,6 +141,12 @@ operations on attached esp32 devices:
 - Using pip: `pip install mp-image-tool-esp32`, or
 - Using uv: `uv tool install mp-image-tool-esp32`.
 
+Support for the `fs` command (reading, checking and copying files to/from
+littlefs filesystems on your device), requires selecting the `littlefs` extra
+eg: `pip install mp-image-tool-esp32[littlefs]`. This has been made available as
+an extra because installing the `littlefs-python` package requires extra build
+tools on your computer, which you may avoid if you don't need filesystem access.
+
 ### Install from github source
 
 I recommend using [`uv`](https://docs.astral.sh/uv/) to install and manage
@@ -467,7 +473,7 @@ options:
                         is appropriate for reading app images from flash
                         storage.
   --fs CMD [CMD ...]    Operate on files in the `vfs` or other filesystem
-                        partitions.
+                        partitions (requires `littlefs-python` installed).
 
 Where SIZE is a decimal or hex number with an optional suffix (M=megabytes,
 K=kilobytes, B=blocks (0x1000=4096 bytes)). --fs commands include: ls, get,

pyproject.toml

@@ -1,7 +1,3 @@
-[build-system]
-requires = ["hatchling", "hatch-vcs"]
-build-backend = "hatchling.build"
-
 [project]
 name = "mp-image-tool-esp32"
 description = "Tool for manipulating micropython ESP32 firmware files"
@@ -18,7 +14,6 @@ classifiers = [
 requires-python = ">=3.8"
 dependencies = [
     "esptool>=4.6.2",
-    "littlefs-python>=0.12.0",
     "rich>=10.12.0",
     "more-itertools>=8.8.0",
     "typing-extensions>=4.12",
@@ -28,10 +23,34 @@ dynamic = ["version"]
 [project.scripts]  # The entry points for the command line tools
 mp-image-tool-esp32 = "mp_image_tool_esp32.main:main"
 
+[project.optional-dependencies]
+littlefs = ["littlefs-python>=0.12.0"]
+
+[dependency-groups]
+typing = ["mypy>=0.910", "types-requests>=2.32.0.20240914", "types-pyserial>=3.5"]
+test = [
+    {include-group = "typing"},
+    "ruff>=0.6.7", "pytest>=8.3.2", "pytest-cov>=3.0.0", "requests>=2.32.3",
+    "pyyaml>=6.0.2", "tox>=4.22.0", "tox-uv>=0.3.0",
+]
+dev = [
+    {include-group = "test"},
+    "keyring>=25",  # For uv publish --keyring-provider=subprocess
+    # Used by .git/hooks/post-{commit,checkout} to update _version.py:
+    #   uv run --frozen hatch build --hooks-only
+    "hatch>=1.12.0",
+    "hatch-vcs>=0.3.0",  # For building and updating _version.py
+]
+
+[build-system]
+requires = ["hatchling", "hatch-vcs"]
+build-backend = "hatchling.build"
+
+# Build python packages and update version number
 [tool.hatch]
-build.hooks.vcs.version-file = "src/mp_image_tool_esp32/_version.py"
 build.targets.wheel.packages = ["src/mp_image_tool_esp32"]
 version.source = "vcs"  # Get the version from git, eg: 0.0.6.dev0+g1234567
+build.hooks.vcs.version-file = "src/mp_image_tool_esp32/_version.py"
 # Drop the local version part (eg: +g1234567) or pypi will reject package
 version.raw-options.local_scheme = "no-local-version"
 # A manually triggered github release workflow may generate a new tag
@@ -45,45 +64,25 @@ version.raw-options.git_describe_command = [
     "--match", "v*.[0-9][0-9][0-9]",
 ]
 
-[tool.uv]
-dev-dependencies = [
-  # For running tests: pytest, pyyaml, requests, tox, mypy, ruff
-  "pytest>=8.3.2",
-  "pyyaml>=6.0.2",
-  "requests>=2.32.3",
-  "tox>=4.0.0",
-  "tox-uv>=0.3.0",  # uv support for tox
-  "pytest-cov>=3.0.0",
-  "mypy>=0.910",  # For code type checks: uv run mypy --no-sources mypy src
-  "types-requests>=2.32.0.20240914",
-  "types-pyserial>=3.5",
-  "ruff>=0.6.7",  # For linting: uv run --no-sources ruff format --check src
-  "keyring>=25",  # For uv publish --keyring-provider=subprocess
-  # Used by .git/hooks/post-{commit,checkout} to update _version.py:
-  #   uv run --frozen hatch build --hooks-only
-  "hatch>=1.12.0",
-  "hatch-vcs>=0.3.0",  # For building and updating _version.py
-]
-
 # https://tox.wiki/en/latest/config.html#pyproject-toml-native
-[tool.tox]  #
+[tool.tox]
+requires = ["tox>=4.22", "tox-uv>=1.13"]
 env_list = [
-    "clean", "mypy", "lint", "format",
+    "clean", "typing", "lint", "format",
     "3.8", "3.9", "3.10", "3.11", "3.12", "3.13"
 ]
-requires = ["tox>=4.19", "tox-uv>=1.13"]
 env.clean.commands = [["coverage", "erase"]]  # Cleanup coverage data
-env.clean.deps = ["coverage"]
 env.clean.skip_install = true
-env.mypy.commands = [["mypy"]]
-env.mypy.deps = ["mypy", "pytest", "types-requests", "types-pyserial"]
+env.typing.commands = [["mypy"]]
 env.lint.commands = [["ruff", "check"]]
-env.lint.deps = ["ruff"]
 env.format.commands = [["ruff", "format", "--check"]]
-env.format.deps = ["ruff"]
+env.3.8.commands = [["pytest", "--cov=mp_image_tool_esp32"]]
+env.3.13.commands = [["pytest", "--cov=mp_image_tool_esp32"]]
 env_run_base.commands = [["pytest"]]
-env_run_base.deps = ["pytest", "pytest-cov", "requests", "pyyaml"]
-env_run_base.package = "editable"
+env_run_base.dependency_groups = ["test"]
+env_run_base.extras = ["littlefs"]  # Include optional dependencies
+env_run_base.package = "wheel"  # Build package wheel and install into environments
+env_run_base.wheel_build_env = ".pkg"  # Re-use one wheel for each environment
 
 [tool.mypy]
 files = ["src"]
@@ -98,12 +97,7 @@ include = ["src/**/*.py"]
 exclude = ["_version.py"]
 lint.extend-select = ["I"]  # Enable ruffs isort rules (for compat with vscode ruff)
 
-[tool.pytest.ini_options]
-minversion = "6.0"
-addopts = ["--cov"]
-
 [tool.coverage]
-run.source = ["src"]
 run.omit = ["_version.py"]
 report.skip_covered = true
 append = true

src/mp_image_tool_esp32/logger.py

@@ -6,7 +6,6 @@
 from typing import Any
 
 import esptool
-import littlefs
 import serial
 from rich.console import Console, ConsoleRenderable
 from rich.highlighter import NullHighlighter
@@ -52,7 +51,7 @@ def render_message(
     show_level=False,
     show_path=False,
     rich_tracebacks=True,
-    tracebacks_suppress=[esptool, serial, littlefs],
+    tracebacks_suppress=[esptool, serial],
 )
 richhandler.setFormatter(logging.Formatter(FORMAT))
 

src/mp_image_tool_esp32/main.py

@@ -26,11 +26,26 @@
 from .argparse_typed import parser as typed_parser
 from .argtypes import MB, ArgList, B, IntArg, PartList
 from .firmware import Firmware
-from .lfs import lfs_cmd
 from .partition_table import PartitionError, PartitionTable
 
 log = logger.getLogger(__name__)
 
+try:
+    from .lfs import lfs_cmd
+except ImportError as err:
+    # If the `littlefs-python` package is not installed, disable the "fs"
+    # command, but allow the rest of the program to run.
+    if err.name != "littlefs":
+        raise err
+
+    def lfs_cmd(firmware: Firmware, command: str, args: list[str] = []) -> None:
+        """A command line processor for LittleFS filesystem operations."""
+        log.error(
+            "'fs' commands require the 'littlefs-python' package. "
+            "Install it with 'pip install littlefs-python'"
+        )
+        raise ImportError("Missing 'littlefs-python' package")
+
 
 # `TypedNamespace` and the `usage` string together provide three things:
 # 1. static type checking for the fields in the namespace returned by