From b419b31efa1fa54919e913fc01b0015381d0fdb3 Mon Sep 17 00:00:00 2001
From: Jan Streffing <jan.streffing@awi.de>
Date: Mon, 29 Jun 2026 11:14:05 +0200
Subject: [PATCH] CI: replace pixi with pip for test + code-quality jobs

The `Test Python Code` and `Code Quality Checks` jobs both failed at the
`pixi install` step (environment resolution), before any code ran. The
pip-based `Build Documentation` job installs the same package fine, so
the breakage is in pixi's resolver, not the project deps.

Switch both jobs to actions/setup-python + pip:
- test-python: apt-install libeccodes-dev (for the gribapi/eccodes
  bindings), pip-install the runtime deps actually imported by the
  tested modules (pyfesom2 is not imported at module top level, so it
  is omitted), then run the syntax + import checks.
- code-quality: pip-install flake8/black/isort and run them directly.

Verified locally: all tracked Python compiles, and the flake8 hard-fail
gate (E9,F63,F7,F82) reports 0 over the tracked tree.
---
 .github/workflows/ci.yml | 62 ++++++++++++++++++++++++++--------------
 1 file changed, 41 insertions(+), 21 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 1aea861..28cf3b1 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -11,23 +11,38 @@ jobs:
   test-python:
     name: Test Python Code
     runs-on: ubuntu-latest
-    
+
     steps:
       - name: Checkout code
         uses: actions/checkout@v4
-      
-      - name: Setup Pixi
-        uses: prefix-dev/setup-pixi@v0.8.1
-      
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.11'
+
+      - name: Install system libraries
+        run: |
+          sudo apt-get update
+          # ecCodes C library so the `gribapi`/`eccodes` Python bindings import
+          sudo apt-get install -y libeccodes-dev
+
+      - name: Install Python dependencies
+        run: |
+          python -m pip install --upgrade pip
+          # Runtime deps needed to import the ocp_tool modules (no conda/pixi).
+          # pyfesom2 is not imported at module top level, so it is not required here.
+          pip install numpy scipy netcdf4 xarray matplotlib cartopy pandas pyyaml eccodes
+
       - name: Check Python scripts syntax
         run: |
-          pixi run python -m py_compile run_ocp_tool.py
-          pixi run python -m py_compile ocp_tool/*.py
+          python -m py_compile run_ocp_tool.py
+          python -m py_compile ocp_tool/*.py
           echo "✓ All Python scripts have valid syntax"
-      
+
       - name: Test import of ocp_tool modules
         run: |
-          pixi run python -c "
+          python -c "
           from ocp_tool.config import load_config, OCPConfig
           from ocp_tool.gaussian_grids import generate_gaussian_grid
           from ocp_tool.lsm import process_land_sea_mask
@@ -40,30 +55,35 @@ jobs:
   code-quality:
     name: Code Quality Checks
     runs-on: ubuntu-latest
-    
+
     steps:
       - name: Checkout code
         uses: actions/checkout@v4
-      
-      - name: Setup Pixi
-        uses: prefix-dev/setup-pixi@v0.8.1
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
         with:
-          environments: dev
-      
+          python-version: '3.11'
+
+      - name: Install linters
+        run: |
+          python -m pip install --upgrade pip
+          pip install flake8 black isort
+
       - name: Run flake8
         run: |
           # Stop the build if there are Python syntax errors or undefined names
-          pixi run -e dev flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics --exclude=.git,__pycache__,build,dist,.pixi
+          flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics --exclude=.git,__pycache__,build,dist,.pixi
           # Exit-zero treats all errors as warnings
-          pixi run -e dev flake8 . --count --exit-zero --max-complexity=15 --max-line-length=120 --statistics --exclude=.git,__pycache__,build,dist,.pixi
-      
+          flake8 . --count --exit-zero --max-complexity=15 --max-line-length=120 --statistics --exclude=.git,__pycache__,build,dist,.pixi
+
       - name: Check code formatting with black
         run: |
-          pixi run -e dev black --check --diff --exclude='(\.git|\.pixi)' . || echo "::warning::Code formatting issues found."
-      
+          black --check --diff --exclude='(\.git|\.pixi)' . || echo "::warning::Code formatting issues found."
+
       - name: Check import sorting with isort
         run: |
-          pixi run -e dev isort --check-only --diff --skip .pixi . || echo "::warning::Import sorting issues found."
+          isort --check-only --diff --skip .pixi . || echo "::warning::Import sorting issues found."
 
   documentation:
     name: Documentation Check