bring back conda

.github/workflows/dev_envs.yml

@@ -45,3 +45,34 @@ jobs:
     - name: run tests for 3.10
       shell: pixi run bash {0}
       run: tox -e py310
+
+  mamba:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, macos-14]
+    steps:
+    - uses: actions/checkout@v4
+      with:
+        fetch-depth: 0
+
+    - name: cache conda
+      uses: actions/cache@v4
+      env:
+        CACHE_NUMBER: 0
+        path: ~/conda_pkgs_dir
+        key:
+          ${{ runner.os }}-conda-${{ env.CACHE_NUMBER }}-${{ hashFiles('environment.yml') }}
+
+    - name: setup conda
+      uses: conda-incubator/setup-miniconda@11b562958363ec5770fef326fe8ef0366f8cbf8a
+      with:
+        python-version: "3.10"
+        miniforge-version: latest
+        environment-file: dev.yml
+        activate-environment: sourmash_dev
+        auto-activate-base: false
+
+    - name: run tests for 3.10
+      shell: bash -l {0}
+      run: tox -e py310

dev.yml

@@ -0,0 +1,12 @@
+name: sourmash_dev
+channels:
+  - conda-forge
+dependencies:
+  - clangdev >=16.0.6,<16.1
+  - cxx-compiler =1.7.*
+  - git =2.41.0.*
+  - libclang >=16,<17
+  - pandoc =3.1.3.*
+  - python =3.10.*
+  - rust =1.75.0.*
+  - tox >=4.11.0,<5

doc/developer.md

@@ -12,12 +12,36 @@ git clone https://github.com/sourmash-bio/sourmash.git
 ```
 sourmash runs under Python 3.10 and later.
 
-We recommend using `pixi` or `Nix` for setting up an environment for developing
+We recommend using `conda` for setting up an environment for developing
 new features, running tests and code quality checks.
-Here are some suggestions on how to set them up (note: you only need one =])
+Here are some suggestions on how to set them up
+
+:::{note}
+You only need one of these, no need to install them all!
+:::
 
 ::::{tab-set}
 
+:::{tab-item} conda
+
+Follow the [installation instructions](https://github.com/conda-forge/miniforge#install) for
+installing `Miniforge3` (a conda distribution that uses
+the [`conda-forge`](https://conda-forge.org/) channel by default).
+
+Once `conda` is installed, run
+```
+conda create -n sourmash_dev -f dev.yml
+```
+to create an environment called `sourmash_dev` containing the programs needed
+for development.
+
+Once the environment is created, you can activate it for development with
+```
+conda activate sourmash_dev
+```
+
+:::
+
 :::{tab-item} pixi
 
 Follow the [installation instructions](https://github.com/prefix-dev/pixi) for