Increase python requirement to >= 3.8 (#2029)

* require python >=3.8

* update CI configurations

* whatsnew

* remove pre-3.8 cruft

* fix h5py/numpy versioning issue for py3.8-min

* update gallery examples for newer pandas

* update asv config for python 3.8

* fix asv config syntax error

* one more asv config edit

Author: kandersolar

.github/workflows/pytest-remote-data.yml

@@ -56,10 +56,10 @@ jobs:
     strategy:
       fail-fast: false  # don't cancel other matrix jobs when one fails
       matrix:
-        python-version: [3.7, 3.8, 3.9, "3.10", "3.11", "3.12"]
+        python-version: [3.8, 3.9, "3.10", "3.11", "3.12"]
         suffix: ['']  # the alternative to "-min"
         include:
-          - python-version: 3.7
+          - python-version: 3.8
             suffix: -min
 
     runs-on: ubuntu-latest
@@ -103,7 +103,7 @@ jobs:
         run: pytest pvlib/tests/iotools --cov=./ --cov-report=xml --remote-data
 
       - name: Upload coverage to Codecov
-        if: matrix.python-version == 3.7 && matrix.suffix == ''
+        if: matrix.python-version == 3.8 && matrix.suffix == ''
         uses: codecov/codecov-action@v4
         with:
           fail_ci_if_error: true

.github/workflows/pytest.yml

@@ -12,12 +12,12 @@ jobs:
       fail-fast: false  # don't cancel other matrix jobs when one fails
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
-        python-version: [3.7, 3.8, 3.9, "3.10", "3.11", "3.12"]
+        python-version: [3.8, 3.9, "3.10", "3.11", "3.12"]
         environment-type: [conda, bare]
         suffix: ['']  # placeholder as an alternative to "-min"
         include:
           - os: ubuntu-latest
-            python-version: 3.7
+            python-version: 3.8
             environment-type: conda
             suffix: -min
         exclude:
@@ -82,7 +82,7 @@ jobs:
           pytest pvlib --cov=./ --cov-report=xml --ignore=pvlib/tests/iotools
 
       - name: Upload coverage to Codecov
-        if: matrix.python-version == 3.7 && matrix.suffix == '' && matrix.os == 'ubuntu-latest' && matrix.environment-type == 'conda'
+        if: matrix.python-version == 3.8 && matrix.suffix == '' && matrix.os == 'ubuntu-latest' && matrix.environment-type == 'conda'
         uses: codecov/codecov-action@v4
         with:
           fail_ci_if_error: true

benchmarks/asv.conf.json

@@ -113,15 +113,15 @@
     "include": [
         // minimum supported versions
         {
-            "python": "3.7",
+            "python": "3.8",
             "build": "",
             "numpy": "1.17.5",
             "pandas": "1.3.0",
             "scipy": "1.6.0",
             // Note: these don't have a minimum in setup.py
             "h5py": "3.1.0",
-            "ephem": "3.7.6.0",
-            "numba": "0.40.0"
+            "ephem": "3.7.7.0",  // first version to support py 3.8
+            "numba": "0.47.0",  // first version to support py 3.8
         },
         // latest versions available
         {

ci/requirements-py3.7.yml

@@ -8,12 +8,12 @@ dependencies:
     - pytest-cov
     - pytest-mock
     - pytest-timeout
-    - python=3.7
+    - python=3.8
     - pytz
     - requests
     - pip:
         - dataclasses
-        - h5py==3.1.0
+        - h5py==2.10.0  # chosen for compatibility with numpy 1.17.3 and py3.8
         - numpy==1.17.3
         - pandas==1.3.0
         - scipy==1.6.0

ci/requirements-py3.7-min.yml renamed to ci/requirements-py3.8-min.yml

@@ -317,7 +317,7 @@ def find_pmp(df):
 
 results = pd.DataFrame(data)
 results['pmp'] /= results['pmp'].max()  # normalize power to 0-1
-results_pivot = results.pivot('fd', 'fs', 'pmp')
+results_pivot = results.pivot(index='fd', columns='fs', values='pmp')
 plt.figure()
 plt.imshow(results_pivot, origin='lower', aspect='auto')
 plt.xlabel('shaded fraction')

docs/examples/shading/plot_partial_module_shading_simple.py

@@ -103,8 +103,7 @@
 
 tz = 'Asia/Calcutta'
 lat, lon = 28.6, 77.2
-times = pd.date_range('2019-01-01 00:00:00', '2020-01-01', closed='left',
-                      freq='H', tz=tz)
+times = pd.date_range('2019-01-01 00:00:00', '2020-01-01', freq='H', tz=tz)
 
 solpos = solarposition.get_solarposition(times, lat, lon)
 # remove nighttime

docs/examples/solar-position/plot_sunpath_diagrams.py

@@ -38,6 +38,7 @@ Documentation
 
 Requirements
 ~~~~~~~~~~~~
+* Python 3.8 or higher. (:issue:`1975`, :pull:`2029`)
 * Minimum version of scipy advanced from 1.5.0 to 1.6.0. (:pull:`2027`)
 
 

docs/sphinx/source/whatsnew/v0.10.5.rst

@@ -1,8 +1,4 @@
-try:
-    from importlib.metadata import PackageNotFoundError, version
-except ImportError:
-    # for python < 3.8
-    from importlib_metadata import PackageNotFoundError, version
+from importlib.metadata import PackageNotFoundError, version
 
 try:
     __version__ = version(__package__)

pvlib/version.py

@@ -9,15 +9,14 @@ description = "A set of functions and classes for simulating the performance of
 authors = [
     { name = "pvlib python Developers", email = "pvlib-admin@googlegroups.com" },
 ]
-requires-python = ">=3.7"
+requires-python = ">=3.8"
 dependencies = [
     'numpy >= 1.17.3',
     'pandas >= 1.3.0',
     'pytz',
     'requests',
     'scipy >= 1.6.0',
     'h5py',
-    'importlib-metadata; python_version < "3.8"',
 ]
 license = { text = "BSD-3-Clause" }
 classifiers = [