CI: Upgrade to free-threaded Python 3.15t (#15105)

* ci: try Python 3.15 release candidate (DRAFT)

Point the repo's .python-version at 3.15 so every workflow that reads
python-version-file runs on the 3.15 release candidate (allow-prereleases
is already enabled across all workflows). Add the 3.15 trove classifier
and bump scipy>=1.18.1, which is the first scipy with cp315 manylinux
wheels, so uv installs it as a wheel rather than building from source.

Rebuilt on current master: the earlier version of this PR edited the
per-workflow `python-version: 3.14` lines, but master has since moved
the interpreter to a single `.python-version` file, so the change is now
a one-line switch there.

Purpose is to document which dependencies/tests are not yet 3.15-ready.
Must stay DRAFT until Python 3.15 GA (early October). Requested in #15081.

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Upgrade to Python 3.15t

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Christian Clauss <cclauss@me.com>

Author: 3 people

.devcontainer/devcontainer.json

@@ -9,12 +9,12 @@
 	//
 	// This repo tracks the latest-and-greatest CPython on the newest stable
 	// Debian. Images are published per CPython minor version on Debian 13
-	// "Trixie" (3.11-trixie ... 3.14-trixie); bump this to the newest available
+	// "Trixie" (3.11-trixie ... 3.15-trixie); bump this to the newest available
 	// when a new stable CPython ships.
-	// NOTE: these images do not publish free-threaded (`t`) variants, so 3.14t
+	// NOTE: these images do not publish free-threaded (`t`) variants, so 3.15t
 	// cannot be selected via the tag alone -- but the repo's `.python-version`
-	// pins 3.14t, and `uv run`/`uv sync` in the container honor it, so uv gives
-	// contributors free-threaded 3.14t regardless of the base tag.
+	// pins 3.15t, and `uv run`/`uv sync` in the container honor it, so uv gives
+	// contributors free-threaded 3.15t regardless of the base tag.
 	"image": "mcr.microsoft.com/devcontainers/python:latest",
 
 	// Install the tools post_install and CI expect (pre-commit + ruff), plus uv

.github/workflows/build.yml

@@ -22,17 +22,15 @@ jobs:
           allow-prereleases: true
       - run: uv sync --group=test
       - name: Run tests
-        # opencv-python is gated out on 3.14t (no cp314t wheel yet), so skip the
+        # opencv-python is gated out on 3.15t (no cp315t wheel yet), so skip the
         # files that import cv2. Pure-Python algorithms in computer_vision/ and
         # data_compression/ still run; digital_image_processing/ is almost entirely
-        # cv2-based so it is skipped as a tree. Re-enable when a cp314t wheel ships.
+        # cv2-based so it is skipped as a tree. Re-enable when a cp315t wheel ships.
         # --ignore-gil-enabled: some compiled deps (sklearn, xgboost, ...) don't
         # yet ship the Py_mod_gil slot, so importing them re-enables the GIL under
-        # 3.14t. That's an upstream-wheel gap, not our code; the flag lets the suite
+        # 3.15t. That's an upstream-wheel gap, not our code; the flag lets the suite
         # run anyway and pytest-run-parallel still reports which tests are not
         # thread-safe. Drop the flag once the scientific stack ships free-threaded wheels.
-        # qiskit is likewise gated out of the 3.14t deps (Qiskit/qiskit#16893), so the
-        # single file that imports it (quantum/q_fourier_transform.py) is skipped too.
         run: uv run --with=pytest-run-parallel pytest
           --iterations=8 --parallel-threads=auto --ignore-gil-enabled
           --ignore=computer_vision/flip_augmentation.py
@@ -42,7 +40,6 @@ jobs:
           --ignore=digital_image_processing/
           --ignore=docs/conf.py
           --ignore=project_euler/
-          --ignore=quantum/q_fourier_transform.py
           --ignore=scripts/validate_solutions.py
           --ignore=web_programming/current_stock_price.py
           --ignore=web_programming/fetch_anime_and_play.py

.github/workflows/ty.yml

@@ -28,16 +28,16 @@ jobs:
       # [build-system], so uv treats the project as virtual and installs only
       # its dependencies -- no "Multiple top-level packages discovered in a
       # flat-layout" error and no need for a src-layout. (`uv pip install .`
-      # would force that wheel build and fail.) Pin a regular GIL 3.14 so typed
-      # third-party dependencies resolve; the free-threaded 3.14t interpreter the
+      # would force that wheel build and fail.) Pin a regular GIL 3.15 so typed
+      # third-party dependencies resolve; the free-threaded 3.15t interpreter the
       # test matrix uses lacks wheels for several of them. ty itself is pulled in
       # ephemerally with `--with` so it needn't be added to the lockfile.
-      - run: uv sync --python 3.14
-      # Pin the *run* to the same regular-GIL 3.14 too. Without `--python 3.14`
+      - run: uv sync --python 3.15
+      # Pin the *run* to the same regular-GIL 3.15 too. Without `--python 3.15`
       # here, `uv run` re-resolved the project's default interpreter -- the
-      # free-threaded 3.14t used by the test matrix -- so ty type-checked against
+      # free-threaded 3.15t used by the test matrix -- so ty type-checked against
       # an env where many third-party stubs don't resolve, drowning real findings
-      # in `unresolved-import` / `unresolved-attribute` noise. Pinning 3.14 lets
+      # in `unresolved-import` / `unresolved-attribute` noise. Pinning 3.15 lets
       # ty see the synced dependencies, so the `[tool.ty.rules]` severities in
       # pyproject.toml apply to a meaningful baseline.
       #
@@ -50,4 +50,4 @@ jobs:
       # to make ty a required gate once the [tool.ty] baseline is clean.
       # `continue-on-error: true` above stays as a belt-and-suspenders guard so a
       # ty *crash* (not a diagnostic) can never block a merge either.
-      - run: uv run --python 3.14 --with ty ty check --output-format=github --exit-zero
+      - run: uv run --python 3.15 --with ty ty check --output-format=github --exit-zero

.python-version

@@ -1 +1 @@
-3.14t
+3.15t

CONTRIBUTING.md

@@ -100,7 +100,7 @@ pre-commit run --all-files --show-diff-on-failure
 
 We want your work to be readable by others; therefore, we encourage you to note the following:
 
-- Please write in free-threaded Python 3.14t+. For instance: `print()` is a function in Python 3, so `print "Hello"` will *not* work, but `print("Hello")` will.
+- Please write in free-threaded Python 3.15t+. For instance: `print()` is a function in Python 3, so `print "Hello"` will *not* work, but `print("Hello")` will.
 
 - Please focus hard on the naming of functions, classes, and variables. Help your reader by using __descriptive names__ that can help you to remove redundant comments.
   - Single-letter variable names are *old school*, so please avoid them unless their life only spans a few lines.

pyproject.toml

@@ -3,10 +3,9 @@ name = "thealgorithms-python"
 version = "0.0.1"
 description = "TheAlgorithms in Python"
 authors = [ { name = "TheAlgorithms Contributors" } ]
-requires-python = ">=3.14"
+requires-python = ">=3.15"
 classifiers = [
   "Programming Language :: Python :: 3 :: Only",
-  "Programming Language :: Python :: 3.14",
   "Programming Language :: Python :: 3.15",
   "Programming Language :: Python :: Free Threading :: 2 - Beta",
 ]
@@ -39,30 +38,21 @@ docs = [
   "sphinx>=8.2",
   "sphinx-autoapi>=3.4",
 ]
-# opencv-python has no free-threaded (cp314t) wheel yet and fails to build from
-# source under 3.14t (CMake), which blocks `uv sync` for every job. Keep it in an
+# opencv-python has no free-threaded (cp315t) wheel yet and fails to build from
+# source under 3.15t (CMake), which blocks `uv sync` for every job. Keep it in an
 # optional group so the free-threaded CI can install everything else and actually
 # run pytest-run-parallel on the pure-Python algorithms. Re-fold into core deps
-# once a cp314t wheel ships (upstream: opencv/opencv#27933).
+# once a cp315t wheel ships (upstream: opencv/opencv#27933).
 cv = [
   "opencv-python>=4.10.0.84",
 ]
 euler-validate = [
   "httpx2>=2.0.1",
   "numpy>=2.1.3",
 ]
-# qiskit does not yet run on free-threaded CPython: its compiled core re-enables
-# the GIL under 3.14t and the team is still scoping free-threading support
-# (upstream: Qiskit/qiskit#16893). Keep it in an optional group so the
-# free-threaded CI can install everything else; only quantum/q_fourier_transform.py
-# imports it, and that file is ignored in the 3.14t test run. Re-fold into core
-# deps once qiskit supports free-threading.
-quantum = [
-  "qiskit>=2",
-]
 
 [tool.ruff]
-target-version = "py314"
+target-version = "py315"
 output-format = "full"
 lint.select = [
   # https://docs.astral.sh/ruff/rules
@@ -321,14 +311,11 @@ skip = """\
   nary.txt,strings/words.txt\
   """
 
-[tool.mypy]
-python_version = "3.14"
-
 [tool.ty]
-# Type-check against a regular (GIL) 3.14 interpreter. Pinning this keeps ty's
+# Type-check against a regular (GIL) 3.15 interpreter. Pinning this keeps ty's
 # assumptions consistent with the CI job in .github/workflows/ty.yml, where the
-# free-threaded 3.14t test venv would otherwise leave several stubs unresolved.
-environment.python-version = "3.14"
+# free-threaded 3.15t test venv would otherwise leave several stubs unresolved.
+environment.python-version = "3.15"
 rules.call-non-callable = "ignore"
 rules.deprecated = "ignore"
 rules.invalid-argument-type = "ignore"