docs: Add DEVELOPMENT.md (#584)

Mostly copied from HUGR's.

drive-by: Remove "experimental execution" (`guppy-runner`) section from
the readme.

DEVELOPMENT.md

@@ -0,0 +1,165 @@
+# Welcome to the Guppy development guide <!-- omit in toc -->
+
+This guide is intended to help you get started with developing guppylang.
+
+If you find any errors or omissions in this document, please [open an issue](https://github.com/CQCL/guppylang/issues/new)!
+
+## #️⃣ Setting up the development environment
+
+You can setup the development environment in two ways:
+
+### The Nix way
+
+The easiest way to setup the development environment is to use the provided
+[`devenv.nix`](devenv.nix) file. This will setup a development shell with all the
+required dependencies.
+
+To use this, you will need to install [devenv](https://devenv.sh/getting-started/).
+Once you have it running, open a shell with:
+
+```bash
+devenv shell
+```
+
+All the required dependencies should be available. You can automate loading the
+shell by setting up [direnv](https://devenv.sh/automatic-shell-activation/).
+
+### Manual setup
+
+To setup the environment manually you will need:
+
+- Just: [just.systems](https://just.systems/)
+- uv `>=0.3`: [docs.astral.sh](https://docs.astral.sh/uv/getting-started/installation/)
+
+The extended test suite has additional requirements. These are **optional**; tests that require them will be skipped if they are not installed.
+
+- Rust `>=1.75`: [rust-lang.org](https://www.rust-lang.org/tools/install)
+- `llvm-14`: [llvm.org](https://llvm.org/)
+
+Once you have these installed, you can install the required python dependencies and setup pre-commit hooks with:
+
+```bash
+just setup
+```
+
+## 🏃 Running the tests
+
+To compile and test the code, run:
+
+```bash
+just test
+# or, to try a specific test
+just test -k test_name
+```
+
+If you have Rust and `llvm-14` installed, this will include the integration
+tests automatically. If you need to export the integration test cases, use:
+
+```bash
+just export-integration-tests
+```
+
+Run `just` to see all available commands.
+
+## 💅 Coding Style
+
+The python code in this repository is formatted using `ruff`. Most IDEs will
+provide automatic formatting on save, but you can also run the formatter manually:
+
+```bash
+just format
+```
+
+We also use various linters to catch common mistakes and enforce best practices. To run these, use:
+
+```bash
+just check
+```
+
+To quickly fix common issues, run:
+
+```bash
+just fix
+```
+
+## 📈 Code Coverage
+
+We run coverage checks on the CI. Once you submit a PR, you can review the
+line-by-line coverage report on
+[codecov](https://app.codecov.io/gh/CQCL/guppylang/commits?branch=All%20branches).
+
+To generate the coverage info locally, simply run:
+
+```bash
+just coverage
+```
+
+and open it with your favourite coverage viewer. In VSCode, you can use
+[`coverage-gutters`](https://marketplace.visualstudio.com/items?itemName=ryanluker.vscode-coverage-gutters).
+
+## 🌐 Contributing to Guppy
+
+We welcome contributions to Guppy! Please open [an issue](https://github.com/CQCL/guppylang/issues/new) or [pull request](https://github.com/CQCL/guppylang/compare) if you have any questions or suggestions.
+
+PRs should be made against the `main` branch, and should pass all CI checks before being merged. This includes using the [conventional commits](https://www.conventionalcommits.org/en/v1.0.0/) format for the PR title.
+
+The general format of a contribution title should be:
+
+```
+<type>(<scope>)!: <description>
+```
+
+Where the scope is optional, and the `!` is only included if this is a semver breaking change that requires a major version bump.
+
+We accept the following contribution types:
+
+- feat: New features.
+- fix: Bug fixes.
+- docs: Improvements to the documentation.
+- style: Formatting, missing semi colons, etc; no code change.
+- refactor: Refactoring code without changing behaviour.
+- perf: Code refactoring focused on improving performance.
+- test: Adding missing tests, refactoring tests; no production code change.
+- ci: CI related changes. These changes are not published in the changelog.
+- chore: Updating build tasks, package manager configs, etc. These changes are not published in the changelog.
+- revert: Reverting previous commits.
+
+## :shipit: Releasing new versions
+
+We use automation to bump the version number and generate changelog entries
+based on the [conventional commits](https://www.conventionalcommits.org/en/v1.0.0/) labels. Release PRs are created automatically
+for each package when new changes are merged into the `main` branch. Once the PR is
+approved by someone in the [release team](.github/CODEOWNERS) and is merged, the new package
+is published on PyPI.
+
+The changelog can be manually edited before merging the release PR. Note however
+that modifying the diff before other changes are merged will cause the
+automation to close the release PR and create a new one to avoid conflicts.
+
+Releases are managed by `release-please`. This tool always bumps the
+minor version (or the pre-release version if the previous version was a
+pre-release).
+
+To override the version getting released, you must merge a PR to `main` containing
+`Release-As: 0.1.0` in the description.
+Python pre-release versions should be formatted as `0.1.0a1` (or `b1`, `rc1`).
+
+### Patch releases
+
+Sometimes we need to release a patch version to fix a critical bug, but we don't want
+to include all the changes that have been merged into the main branch. In this case,
+you can create a new branch from the latest release tag and cherry-pick the commits
+you want to include in the patch release.
+
+You will need to modify the version and changelog manually in this case. Check
+the existing release PRs for examples on how to do this. Once the branch is
+ready, create a draft PR so that the release team can review it.
+
+The wheel building process and publication to PyPI is handled by the CI. Just
+create a [github release](https://github.com/CQCL/guppylang/releases/new) from
+the **unmerged** branch, and the CI will take care of the rest. The release tag
+should follow the format used in the previous releases, e.g. `v0.1.1`.
+
+After the release is published, make sure to merge the changes to the CHANGELOG
+and versions back into the `main` branch. This may be done by cherry-picking the
+PR used to create the release.

README.md

@@ -56,73 +56,7 @@ See the [Getting Started][getting-started] guide and the other [examples].
 
 ## Development
 
-These instructions will get you a copy of the project up and running on your local machine for development and testing purposes.
-
-### Prerequisites
-
-- [uv](https://docs.astral.sh/uv/getting-started/installation/)
-- [Rust](https://www.rust-lang.org/tools/install) >= 1.75.0  (only needed for tests)
-
-### Installing
-
-Run the following to setup your virtual environment and install dependencies:
-
-```sh
-uv sync --extra execution
-cargo build --release  # Builds the validator (optional)
-```
-
-Note that the `--extra` flag, and the `cargo build` line, are both optional, but enable some integration tests.
-
-The validator allows the tests to validate that the hugrs guppy outputs are well formed, and the `execution` extra allows tests to compile these hugrs to native code using [hugr-llvm](https://github.com/CQCL/hugr-llvm) to check the results are as expected.
-This requires `llvm-14` as described in the `hugr-llvm` repo.
-
-Consider using [direnv](https://direnv.net/docs/installation.html) to
-automate this when entering and leaving a directory.
-
-To run a single command in the shell, just prefix it with `uv run`.
-
-### Pre-commit
-
-Install the pre-commit hook by running:
-
-```sh
-uv run pre-commit install
-```
-
-
-### Testing
-
-Run tests using
-
-```sh
-uv run pytest [-v]  # -v just enables verbose test output
-```
-
-(If you have not built the validator, you can do `uv run pytest --no_validation`.)
-
-You have to install extra dependencies to test automatic circuit conversion from `pytket`.
-
-```sh
-# Install extra dependencies
-# Using `--inexact` to avoid removing the already installed extras.
-uv sync --extra pytket --inexact
-# Now rerun tests
-uv run pytest -v
-```
-
-
-Integration test cases can be exported to a directory using
-
-```sh
-uv run pytest --export-test-cases=guppy-exports
-```
-
-which will create a directory `./guppy-exports` populated with hugr modules serialised in JSON.
-
-### Experimental: Execution
-
-See the [guppy-runner](https://github.com/CQCL/guppy-runner) repository for in-progress work for compiling Guppy source programs and executing them.
+See [DEVELOPMENT.md](https://github.com/CQCL/guppylang/blob/main/DEVELOPMENT.md) for instructions on setting up the development environment.
 
 ## License
 

justfile

@@ -16,14 +16,21 @@ setup-extras:
 check:
     uv run pre-commit run --all-files
 
-# Run the tests that don't require the validator or execution.
-test *PYTEST_FLAGS:
+# Compile integration test binaries.
+_prepare-test:
     # Build the validator binary if rust is installed. Otherwise, skip it.
     cargo build --release -p validator || true
     # Build the execution binary if rust is installed. Otherwise, skip it.
     uv run maturin build -m execute_llvm/Cargo.toml --release || true
+
+# Run the tests.
+test *PYTEST_FLAGS: _prepare-test
     uv run pytest {{PYTEST_FLAGS}}
 
+# Export the integration test cases to a directory.
+export-integration-tests directory="guppy-exports": _prepare-test
+    uv run pytest --export-test-cases="{{ directory }}"
+
 # Auto-fix all clippy warnings.
 fix:
     uv run ruff check --fix guppylang