Mono repo template

copier.yml

@@ -1,2 +1,18 @@
 _subdirectory: template
 _answers_file: .copier-answers.ess.yml
+# Questions
+subpackages:
+  type: yaml
+  multiline: true
+  help: Subpackages information. Name, description and dependencies.
+  default:
+    # Include the existing packages as defaults for easier template settings for now.
+    # They should be deleted once we have the answer file in the ess project.
+    - name: essreduce
+      description: Common data reduction tools (core)
+      dependencies: []
+    - name: essimaging
+      description: Neutron imaging (ODIN, TBL, YMIR)
+      dependencies:
+        - essreduce
+

template/README.md.jinja

@@ -0,0 +1,112 @@
+# ESS Data Reduction Monorepo
+
+Monorepo for ESS neutron scattering data reduction packages, managed with [pixi](https://pixi.sh/).
+
+| Package | Description |
+|---------|-------------|
+{% for package in subpackages %}| [{{ package.name }}](packages/{{ package.name }}/) | {{ package.description }} |
+{% endfor %}
+## Dependency graph
+
+```
+essreduce
+└── essimaging
+```
+
+---
+
+## Developer Guide
+
+### Prerequisites
+
+Install [pixi](https://pixi.sh/):
+
+```bash
+curl -fsSL https://pixi.sh/install.sh | bash
+```
+
+### Setup
+
+```bash
+git clone git@github.com:scipp/ess.git
+cd ess
+
+# Install all packages (editable, with test deps):
+pixi install
+
+# Or just one package:
+pixi install -e essreduce
+```
+
+The `pixi.lock` file pins all dependencies reproducibly. No tox, no pip-compile, no manual virtualenv.
+
+### Running tests
+
+```bash
+# Test a package:
+pixi run test essreduce
+pixi run test essimaging
+
+# Test a single file:
+pixi run -e essreduce pytest packages/essreduce/tests/normalization_test.py
+```
+
+### Linting and formatting
+
+```bash
+pixi run -e lint lint       # all pre-commit hooks
+pixi run -e lint check      # ruff check
+pixi run -e lint format     # ruff format
+```
+
+### Building docs
+
+```bash
+pixi run docs essreduce
+pixi run docs essimaging
+```
+
+### Adding or changing dependencies
+
+Edit the package's `pyproject.toml`, then re-lock:
+
+```bash
+pixi install
+```
+
+Commit the updated `pixi.lock`.
+
+### Releasing a package
+
+Push a tag with the package prefix:
+
+```bash
+git tag essreduce/26.3.0
+git push origin main --tags
+```
+
+The `release.yml` workflow builds, publishes to PyPI, and deploys docs.
+
+### How CI works
+
+- **On PRs:** Only changed packages are tested (changing `essreduce` also tests `essimaging`)
+- **Nightly:** All packages tested against latest deps + lower-bound deps
+- **Weekly:** All packages tested on macOS and Windows
+
+### Repo structure
+
+```
+pixi.toml                  ← workspace root (features, tasks, environments)
+pixi.lock                  ← single lockfile for all packages
+.pre-commit-config.yaml    ← shared linting hooks
+packages/
+  essreduce/
+    pyproject.toml          ← package deps, version, pytest config
+    src/ess/reduce/         ← source code (ess.reduce namespace)
+    tests/
+    docs/
+  essimaging/
+    pyproject.toml
+    src/ess/imaging/        ← source code (ess.imaging namespace)
+    ...
+```

template/pixi.toml.jinja

@@ -0,0 +1,62 @@
+[workspace]
+name = "ess"
+channels = ["conda-forge"]
+platforms = ["linux-64", "osx-64", "osx-arm64", "win-64"]
+version = "2026.2.0"
+
+[dependencies]
+python = "3.11.*"
+
+# ==================== Parameterized tasks ====================
+
+[tasks.test]
+cmd = "pytest packages/{% raw %}{{ package }}{% endraw %}/tests/"
+args = ["package"]
+
+[tasks.docs]
+cmd = "python -m sphinx -v -b html -d /tmp/docs_doctrees packages/{% raw %}{{ package }}{% endraw %}/docs packages/{% raw %}{{ package }}{% endraw %}/html"
+args = ["package"]
+
+# ==================== Package features ====================
+
+{% for package in subpackages %}# {{ package.name }} {% if package.name == "essreduce" %}(core package, no workspace deps){% else %}(depends on {{ ', '.join(package.dependencies) }}){% endif %}
+[feature.{{ package.name }}.pypi-dependencies]
+{{ package.name }} = { path = "packages/{{ package.name }}", editable = true, extras = ["test"] }
+
+{% endfor %}# ==================== Lint feature ====================
+
+[feature.lint.pypi-dependencies]
+pre-commit = "*"
+ruff = ">=0.15"
+
+[feature.lint.tasks]
+lint = "pre-commit run --all-files"
+check = "ruff check ."
+format = "ruff format ."
+
+# ==================== Docs feature ====================
+
+[feature.docs.dependencies]
+pandoc = "*"
+
+# Per-package docs features (install with docs extra)
+{% for package in subpackages %}[feature.docs-{{ package.name }}.pypi-dependencies]
+{{ package.name }} = { path = "packages/{{ package.name }}", editable = true, extras = ["test", "docs"] }
+
+{% endfor %}# ==================== Environments ====================
+
+[environments]
+# Default: all packages (for full dev setup)
+default = { features = [{% for package in subpackages %}"{{ package.name }}"{% if not loop.last %}, {% endif %}{% endfor %}], solve-group = "default" }
+
+# Per-package test environments (include workspace dep features)
+{% for package in subpackages %}{{ package.name }} = { features = ["{{ package.name }}"{% if package.dependencies %}, {% endif %}{% for dep in package.dependencies %}"{{ dep }}"{% if not loop.last %}, {% endif %}{% endfor %}], solve-group = "default" }
+{% endfor %}
+# Lower-bound test environments (separate resolution)
+{% for package in subpackages %}lb-{{ package.name }} = { features = ["{{ package.name }}"{% if package.dependencies %}, {% endif %}{% for dep in package.dependencies %}"{{ dep }}"{% if not loop.last %}, {% endif %}{% endfor %}], solve-group = "lower-bound" }
+{% endfor %}
+# Docs environments (package with docs extra + pandoc)
+{% for package in subpackages %}docs-{{ package.name }} = { features = ["docs-{{ package.name }}", {% for dep in package.dependencies %}"docs-{{ dep }}", {% endfor %}"docs"], solve-group = "default" }
+{% endfor %}
+# Lint environment (standalone, no package deps)
+lint = { features = ["lint"], solve-group = "lint" }