Add dev container configuration

.devcontainer/devcontainer-lock.json

@@ -0,0 +1,14 @@
+{
+  "features": {
+    "ghcr.io/devcontainers-extra/features/pandoc:1": {
+      "version": "1.0.15",
+      "resolved": "ghcr.io/devcontainers-extra/features/pandoc@sha256:c700be82b7d6448aac4bae5bd97745a3c031870ba98e34269e8052d06868849f",
+      "integrity": "sha256:c700be82b7d6448aac4bae5bd97745a3c031870ba98e34269e8052d06868849f"
+    },
+    "ghcr.io/devcontainers-extra/features/uv:1": {
+      "version": "1.0.2",
+      "resolved": "ghcr.io/devcontainers-extra/features/uv@sha256:1ac5b9f17a9e9e745933d0ac2ecf758e06ed3da4423cd22c94cce4d482fd2dd8",
+      "integrity": "sha256:1ac5b9f17a9e9e745933d0ac2ecf758e06ed3da4423cd22c94cce4d482fd2dd8"
+    }
+  }
+}

.devcontainer/devcontainer.json

@@ -0,0 +1,33 @@
+{
+  "name": "python-blosc2",
+  "image": "mcr.microsoft.com/devcontainers/python:3-3.12",
+  "features": {
+    "ghcr.io/devcontainers-extra/features/uv:1": {},
+    // nbsphinx needs pandoc to render the notebooks in doc/
+    "ghcr.io/devcontainers-extra/features/pandoc:1": {}
+  },
+  // Already set by Microsoft's container, but more clear for /home below
+  "remoteUser": "vscode",
+  "containerEnv": {
+    // Keep the venv out of the bind-mounted checkout so it never collides with a host-side .venv
+    "UV_PROJECT_ENVIRONMENT": "/home/vscode/.venv"
+  },
+  "remoteEnv": {
+    "PATH": "/home/vscode/.venv/bin:${containerEnv:PATH}"
+  },
+  "updateContentCommand": "uv sync --group dev --group test --group doc && pre-commit install",
+  "customizations": {
+    "vscode": {
+      "settings": {
+        "python.defaultInterpreterPath": "/home/vscode/.venv/bin/python",
+        "[python]": {
+          "editor.defaultFormatter": "charliermarsh.ruff"
+        }
+      },
+      "extensions": [
+        "ms-python.python",
+        "charliermarsh.ruff"
+      ]
+    }
+  }
+}

README_DEVELOPERS.md

@@ -49,6 +49,41 @@ pre-commit install
 
 Pre-commit will now run automatically on `git commit`.
 
+### Using a dev container
+
+As an alternative to a local setup, the repository includes a
+[dev container](https://containers.dev) configuration in `.devcontainer/`.  It
+provides a Linux environment with Python 3.12 (to match the version used by the
+main CI test job), uv, and pandoc, and uses uv to install the `dev`, `test` and
+`doc` groups for you.
+
+You need Docker (or a compatible engine) and a client that supports dev
+containers, such as VS Code with the
+[Dev Containers](https://marketplace.visualstudio.com/items?itemName=ms-vscode-remote.remote-containers)
+extension (or Cursor or a similar fork with a compatible extension), GitHub
+Codespaces, or the
+[`devcontainer` CLI](https://github.com/devcontainers/cli).  In VS Code, open the
+repository and run **Dev Containers: Reopen in Container**.  The first build
+compiles the C extension and takes a few minutes; later sessions reuse the
+container and so skip the compilation and launch faster.
+
+Things to know:
+
+- The virtual environment lives at `/home/vscode/.venv`, outside the checkout,
+  and is on `PATH`, so `pytest`, `python -m sphinx`, etc. work as shown in this
+  document.  A `.venv` created on the host is ignored.
+- The pre-commit hook is installed for you.  The `.git` directory is shared with
+  the host (i.e., your computer outside the container), which means the same hook
+  also runs for commits made on the host.  Be sure to run commits from inside the
+  container; committing from the host requires `pre-commit` to be installed there
+  as well.
+- After dependencies change in `pyproject.toml`, run
+  `uv sync --group dev --group test --group doc` again, or rebuild the container.
+- On Windows, clone the repository inside the WSL filesystem (or use **Dev
+  Containers: Clone Repository in Container Volume**).  A checkout on a Windows
+  drive (e.g., `C:\`) is mounted through a slow file-sharing layer, so avoid
+  opening the dev container straight from a Windows checkout, where you can.
+
 ### On Windows
 
 clang-cl is required.  Make sure LLVM is on `PATH` and build with Ninja: