fix: use hatch's default env so the uv installer is inherited (#4023)

* fix: use hatch's `default` env so the uv installer is inherited

`[tool.hatch.envs.defaults]` (plural) is a standalone environment that
nothing inherits from — hatch's base environment is `default` (singular).
As written, `installer = "uv"` never applied to `test`, `docs`, etc., so
those envs fell back to the `virtualenv` backend.

This breaks contributors whose Python is uv-managed: hatch hands the
`~/.local/bin/pythonX.Y` symlink to virtualenv, which mis-relocates the
python-build-standalone interpreter (`sys.base_prefix = '/install'`,
`ModuleNotFoundError: No module named 'encodings'`). Creating the env with
`uv venv` relocates it correctly.

Renaming to `default` makes the intended uv installer apply to all envs.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* ci: install uv in hatch-based workflows so the uv installer works

Activating `installer = "uv"` (via the `default` env fix) means hatch now
needs a uv binary to create/sync the test, gputest and hypothesis envs.
These workflows install hatch via the `pypa/hatch` action (a pyapp build
with its own bundled Python) but never set up uv, so hatch fell back to
provisioning uv through its pyapp runtime — whose `pip` has a `python3.12`
shebang that doesn't exist on non-3.12 runners:

    .../pyapp/hatch/.../python/bin/python3.12: No such file or directory
    Process completed with exit code 126

Add the repo's standard `astral-sh/setup-uv` step (already used by docs/lint
workflows) before "Install Hatch" so hatch finds uv on PATH and uses it
directly. With uv available, `uv venv --python <matrix>` selects the correct
interpreter, so the root `.python-version` (3.12, for the dev env) no longer
interferes with the 3.13/3.14 matrix envs.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* ci: point hatch at the setup-uv binary to skip its broken uv bootstrap

Installing uv on PATH is not enough: hatch only skips provisioning its
internal `hatch-uv` env when an explicit uv path is set. Otherwise it
bootstraps uv via its bundled pyapp `pip` (shebang `python3.12`), which
fails on non-3.12 runners with exit code 126.

Set `HATCH_ENV_TYPE_VIRTUAL_UV_PATH=uv` so hatch uses the uv provided by
astral-sh/setup-uv directly instead of bootstrapping. Verified locally:
with the explicit path set, `hatch env create` succeeds.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* ci(test): install hatch via pip instead of the pyapp action

The macOS jobs failed even with uv on PATH: hatch's pyapp (standalone)
build on macOS has a `pip` whose shebang points at a non-existent
`python3.12`, and activating the uv installer makes hatch invoke it
(`exit code 126`). Linux pyapp builds are unaffected, which is why the
GPU and Hypothesis (Linux) workflows pass.

Install hatch with `python -m pip install hatch==1.16.5` (the method the
contributing docs already document) so hatch runs on the runner's normal
Python with a working pip on every OS. uv (from setup-uv) is still used as
the env installer.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

Author: lhoupert

.github/workflows/gpu_test.yml

@@ -12,6 +12,8 @@ on:
 
 env:
   LD_LIBRARY_PATH: /usr/local/cuda/extras/CUPTI/lib64:/usr/local/cuda/lib64
+  # Use the uv from astral-sh/setup-uv instead of hatch's bundled (pyapp) uv.
+  HATCH_ENV_TYPE_VIRTUAL_UV_PATH: uv
 
 permissions:
   contents: read
@@ -59,6 +61,8 @@ jobs:
       with:
         python-version: ${{ matrix.python-version }}
         cache: 'pip'
+    - name: Install uv
+      uses: astral-sh/setup-uv@08807647e7069bb48b6ef5acd8ec9567f424441b # v8.1.0
     - name: Install Hatch
       uses: pypa/hatch@257e27e51a6a5616ed08a39a408a21c35c9931bc
       with:

.github/workflows/hypothesis.yaml

@@ -18,6 +18,8 @@ concurrency:
 
 env:
   FORCE_COLOR: 3
+  # Use the uv from astral-sh/setup-uv instead of hatch's bundled (pyapp) uv.
+  HATCH_ENV_TYPE_VIRTUAL_UV_PATH: uv
 
 jobs:
 
@@ -54,6 +56,8 @@ jobs:
       with:
         python-version: ${{ matrix.python-version }}
         cache: 'pip'
+    - name: Install uv
+      uses: astral-sh/setup-uv@08807647e7069bb48b6ef5acd8ec9567f424441b # v8.1.0
     - name: Install Hatch
       uses: pypa/hatch@257e27e51a6a5616ed08a39a408a21c35c9931bc
       with:

.github/workflows/test.yml

@@ -13,6 +13,11 @@ on:
 permissions:
   contents: read
 
+env:
+  # Use the uv from astral-sh/setup-uv; without an explicit path hatch
+  # bootstraps its own (pyapp) uv, which fails on non-3.12 runners.
+  HATCH_ENV_TYPE_VIRTUAL_UV_PATH: uv
+
 concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}
   cancel-in-progress: true
@@ -60,10 +65,10 @@ jobs:
       with:
         python-version: ${{ matrix.python-version }}
         cache: 'pip'
+    - name: Install uv
+      uses: astral-sh/setup-uv@08807647e7069bb48b6ef5acd8ec9567f424441b # v8.1.0
     - name: Install Hatch
-      uses: pypa/hatch@257e27e51a6a5616ed08a39a408a21c35c9931bc
-      with:
-        version: '1.16.5'
+      run: python -m pip install hatch==1.16.5
     - name: Set Up Hatch Env
       env:
         HATCH_ENV: test.py${{ matrix.python-version }}-${{ matrix.dependency-set }}
@@ -109,10 +114,10 @@ jobs:
       with:
         python-version: ${{ matrix.python-version }}
         cache: 'pip'
+    - name: Install uv
+      uses: astral-sh/setup-uv@08807647e7069bb48b6ef5acd8ec9567f424441b # v8.1.0
     - name: Install Hatch
-      uses: pypa/hatch@257e27e51a6a5616ed08a39a408a21c35c9931bc
-      with:
-        version: '1.16.5'
+      run: python -m pip install hatch==1.16.5
     - name: Set Up Hatch Env
       env:
         HATCH_ENV: ${{ matrix.dependency-set }}
@@ -144,10 +149,10 @@ jobs:
       with:
         python-version: '3.13'
         cache: 'pip'
+    - name: Install uv
+      uses: astral-sh/setup-uv@08807647e7069bb48b6ef5acd8ec9567f424441b # v8.1.0
     - name: Install Hatch
-      uses: pypa/hatch@257e27e51a6a5616ed08a39a408a21c35c9931bc
-      with:
-        version: '1.16.5'
+      run: python -m pip install hatch==1.16.5
     - name: Set Up Hatch Env
       run: |
         hatch run doctest:pip list
@@ -168,10 +173,10 @@ jobs:
       with:
         python-version: '3.13'
         cache: 'pip'
+    - name: Install uv
+      uses: astral-sh/setup-uv@08807647e7069bb48b6ef5acd8ec9567f424441b # v8.1.0
     - name: Install Hatch
-      uses: pypa/hatch@257e27e51a6a5616ed08a39a408a21c35c9931bc
-      with:
-        version: '1.16.5'
+      run: python -m pip install hatch==1.16.5
     - name: Run Benchmarks
       run: |
         hatch env run --env "test.py3.13-minimal" run-benchmark

pyproject.toml

@@ -257,7 +257,7 @@ extra-dependencies = [
     'obstore==0.5.*',
 ]
 
-[tool.hatch.envs.defaults]
+[tool.hatch.envs.default]
 installer = "uv"
 
 [tool.hatch.envs.docs]