Test and build wheels on Python 3.15

.github/workflows/build-and-upload-to-pypi.yml

@@ -54,7 +54,15 @@ jobs:
         # "Unknown enable group". cp313t is not buildable at this pin at any
         # setting, so 3.13t is covered by test.yml instead. Build selection
         # follows requires-python (>=3.10) in pyproject.toml.
-        uses: pypa/cibuildwheel@v4.1.0
+        #
+        # 4.2.0 is the first pin that knows about CPython 3.15, and it builds
+        # and tests cp315/cp315t by default -- no `CIBW_ENABLE:
+        # cpython-prerelease` needed. cibuildwheel gates a Python behind that
+        # enable group only until its first release candidate, because the ABI
+        # is frozen at rc1; 3.15.0rc1 is out, so wheels built here are
+        # forward-compatible with 3.15.0 final. (Under the previous 4.1.0 pin
+        # 3.15 could not be built at all, at any setting.)
+        uses: pypa/cibuildwheel@v4.2.0
         env:
           CIBW_ARCHS: ${{ matrix.cibw_archs }}
 

.github/workflows/test-system-uchardet.yml

@@ -19,6 +19,8 @@ jobs:
   system-uchardet:
     name: Build against system uchardet (from git), Python ${{ matrix.python-version }}
     runs-on: ubuntu-latest
+    # Only the 3.15 row below sets this; the rest stay hard requirements.
+    continue-on-error: ${{ matrix.experimental }}
     strategy:
       fail-fast: false
       matrix:
@@ -30,6 +32,14 @@ jobs:
         # cibuildwheel cannot produce cp313t wheels at all, which makes 3.13t
         # the least-covered configuration in the project overall.
         python-version: ['3.12', '3.13t', '3.14t']
+        experimental: [false]
+        include:
+          # Free-threaded 3.15 (a pre-release; see test.yml for why these rows
+          # are advisory and how to promote them). The system build is where a
+          # new interpreter is most likely to break first: it compiles against
+          # upstream uchardet's headers rather than the vendored sources.
+          - python-version: '3.15t'
+            experimental: true
 
     steps:
       - uses: actions/checkout@v4
@@ -43,6 +53,8 @@ jobs:
         uses: actions/setup-python@v5
         with:
           python-version: ${{ matrix.python-version }}
+          # Required for the 3.15 row; see test.yml for the full reasoning.
+          allow-prereleases: true
 
       - name: Build and install uchardet from git
         run: |

.github/workflows/test.yml

@@ -12,16 +12,37 @@ jobs:
   test:
     name: Test on Python ${{ matrix.python-version }}
     runs-on: ubuntu-latest
+    # Only the 3.15 rows below set this; every other row is `false` and stays
+    # a hard requirement.
+    continue-on-error: ${{ matrix.experimental }}
     strategy:
       fail-fast: false
       matrix:
         # Python 3.9 was dropped; 3.13 and 3.14 are required to pass.
         # The `t` entries are the free-threaded (no-GIL) builds. They are the
         # only coverage for the freethreading_compatible declaration -- without
         # them a regression is invisible until someone imports cchardet on a
-        # free-threaded interpreter. Note cibuildwheel 4.1.0 cannot build
+        # free-threaded interpreter. Note cibuildwheel 4.2.0 still cannot build
         # cp313t wheels at all, so 3.13t is tested here or nowhere.
         python-version: ['3.10', '3.11', '3.12', '3.13', '3.14', '3.13t', '3.14t']
+        experimental: [false]
+        include:
+          # Python 3.15, resolved by `allow-prereleases` below to whatever
+          # pre-release the runner image currently publishes -- 3.15.0rc1 at
+          # the time of writing, and 3.15.0 final once it ships, with no change
+          # needed here. Both the default and the free-threaded build, matching
+          # the coverage the 3.14 rows get.
+          #
+          # Advisory (`continue-on-error`) while 3.15 is a pre-release: the
+          # extension builds and the suite passes on 3.15.0rc1 today, but rc2
+          # and the final release are still to come and a CPython-side
+          # regression must not block merges. Move these entries up into the
+          # `python-version` list to make 3.15 a required check once 3.15.0
+          # final is out.
+          - python-version: '3.15'
+            experimental: true
+          - python-version: '3.15t'
+            experimental: true
 
     steps:
       - uses: actions/checkout@v4
@@ -35,6 +56,12 @@ jobs:
         uses: actions/setup-python@v5
         with:
           python-version: ${{ matrix.python-version }}
+          # Needed for the 3.15 rows -- a bare `3.15` only matches stable
+          # releases and fails with "Version 3.15 was not found in the local
+          # cache". Harmless for the rest: this widens `3.X` to `~3.X.0-0`, and
+          # a pre-release is only chosen when no stable release satisfies the
+          # spec, so 3.10-3.14 still resolve to their newest stable patch.
+          allow-prereleases: true
 
       - name: Install package and test dependencies
         run: |

pyproject.toml

@@ -36,6 +36,7 @@ classifiers = [
     "Programming Language :: Python :: 3.12",
     "Programming Language :: Python :: 3.13",
     "Programming Language :: Python :: 3.14",
+    "Programming Language :: Python :: 3.15",
     # Tier 2: multithreaded use is tested and the thread-safety caveats are
     # documented (detect() is safe to call concurrently; a UniversalDetector
     # instance is per-stream and must not be shared). See the README.

tox.ini

@@ -1,5 +1,8 @@
 [tox]
-envlist = py36, py37, py38, py39, py310, py311
+# Matches requires-python (>=3.10) in pyproject.toml and the matrix in
+# .github/workflows/test.yml. py315 is Python 3.15, still a pre-release --
+# tox will skip it unless a 3.15 interpreter is on PATH.
+envlist = py310, py311, py312, py313, py314, py315
 
 [testenv]
 whitelist_externals = make