chore: drop support for Python 3.8 as it is now EOL

.github/workflows/build.yml

@@ -5,7 +5,7 @@ on: [push, pull_request]
 env:
   CIBW_ENVIRONMENT_PASS_LINUX: PYTEST_TIMEOUT
   CIBW_TEST_COMMAND: "cd {project} && pip install --prefer-binary '.[test]' && python -m pytest -v tests"
-  CIBW_SKIP: "cp36-* cp37-* pp37-*"
+  CIBW_SKIP: "cp36-* cp37-* cp38-* pp37-*"
   PYTEST_TIMEOUT: 60
   MACOSX_DEPLOYMENT_TARGET: "10.9"
 
@@ -27,7 +27,7 @@ jobs:
       - uses: actions/setup-python@v5
         name: Install Python
         with:
-          python-version: '3.8'
+          python-version: '3.9'
 
       - name: Build wheels (manylinux)
         uses: pypa/[email protected]
@@ -140,12 +140,12 @@ jobs:
       - uses: actions/setup-python@v5
         name: Install Python
         with:
-          python-version: '3.8'
+          python-version: '3.9'
 
       - name: Install OS dependencies
         if: steps.cache-c-core.outputs.cache-hit != 'true' || steps.cache-c-deps.outputs.cache-hit != 'true' # Only needed when building the C core or libomp
         run:
-          brew install ninja autoconf automake libtool cmake
+          brew install ninja autoconf automake libtool
 
       - name: Install OpenMP library
         if: steps.cache-c-deps.outputs.cache-hit != 'true'
@@ -235,7 +235,7 @@ jobs:
       - uses: actions/setup-python@v5
         name: Install Python
         with:
-          python-version: '3.8'
+          python-version: '3.9'
 
       - name: Cache installed C core
         id: cache-c-core
@@ -305,7 +305,7 @@ jobs:
       - uses: actions/setup-python@v5
         name: Install Python
         with:
-          python-version: '3.8'
+          python-version: '3.9'
 
       - name: Build sdist
         run: |

README.md

@@ -302,7 +302,7 @@ faster than the first one as the C core does not need to be recompiled.
 
 We aim to keep up with the development cycle of Python and support all official
 Python versions that have not reached their end of life yet. Currently this
-means that we support Python 3.8 to 3.12, inclusive. Please refer to [this
+means that we support Python 3.9 to 3.13, inclusive. Please refer to [this
 page](https://devguide.python.org/versions/) for the status of Python
 branches and let us know if you encounter problems with `igraph` on any
 of the non-EOL Python versions.

setup.py

@@ -7,8 +7,8 @@
 ###########################################################################
 
 # Check Python's version info and exit early if it is too old
-if sys.version_info < (3, 8):
-    print("This module requires Python >= 3.8")
+if sys.version_info < (3, 9):
+    print("This module requires Python >= 3.9")
     sys.exit(0)
 
 ###########################################################################
@@ -916,8 +916,6 @@ def get_tag(self):
     bdist_wheel_abi3 = None
 
 # We are going to build an abi3 wheel if we are at least on CPython 3.9.
-# This is because the C code contains conditionals for CPython 3.8 so we cannot
-# use an abi3 wheel built with CPython 3.8 on CPython 3.9
 should_build_abi3_wheel = (
     bdist_wheel_abi3
     and platform.python_implementation() == "CPython"
@@ -1039,7 +1037,7 @@ def get_tag(self):
             "pydoctor>=23.4.0",
         ],
     },
-    "python_requires": ">=3.8",
+    "python_requires": ">=3.9",
     "headers": headers,
     "platforms": "ALL",
     "keywords": [
@@ -1057,7 +1055,6 @@ def get_tag(self):
         "Operating System :: OS Independent",
         "Programming Language :: C",
         "Programming Language :: Python :: 3",
-        "Programming Language :: Python :: 3.8",
         "Programming Language :: Python :: 3.9",
         "Programming Language :: Python :: 3.10",
         "Programming Language :: Python :: 3.11",

src/_igraph/bfsiter.c

@@ -121,10 +121,7 @@ static int igraphmodule_BFSIter_traverse(igraphmodule_BFSIterObject *self,
 				  visitproc visit, void *arg) {
   RC_TRAVERSE("BFSIter", self);
   Py_VISIT(self->gref);
-#if PY_VERSION_HEX >= 0x03090000
-  // This was not needed before Python 3.9 (Python issue 35810 and 40217)
   Py_VISIT(Py_TYPE(self));
-#endif
   return 0;
 }
 

src/_igraph/dfsiter.c

@@ -122,10 +122,7 @@ static int igraphmodule_DFSIter_traverse(igraphmodule_DFSIterObject *self,
 				  visitproc visit, void *arg) {
   RC_TRAVERSE("DFSIter", self);
   Py_VISIT(self->gref);
-#if PY_VERSION_HEX >= 0x03090000
-  // This was not needed before Python 3.9 (Python issue 35810 and 40217)
   Py_VISIT(Py_TYPE(self));
-#endif
   return 0;
 }
 

src/_igraph/graphobject.c

@@ -141,10 +141,7 @@ int igraphmodule_Graph_traverse(igraphmodule_GraphObject * self,
     }
   }
 
-#if PY_VERSION_HEX >= 0x03090000
-  // This was not needed before Python 3.9 (Python issue 35810 and 40217)
   Py_VISIT(Py_TYPE(self));
-#endif
 
   return 0;
 }