Merge branch 'main' into close-escapes-2

Author: markshannon

.github/workflows/build.yml

@@ -512,26 +512,59 @@ jobs:
       run: xvfb-run make ci
 
   build_tsan:
-    name: 'Thread sanitizer'
+    name: >-
+      Thread sanitizer
+      ${{ fromJSON(matrix.free-threading) && '(free-threading)' || '' }}
     needs: check_source
     if: needs.check_source.outputs.run_tests == 'true'
+    strategy:
+      matrix:
+        free-threading:
+        - false
+        - true
     uses: ./.github/workflows/reusable-tsan.yml
     with:
       config_hash: ${{ needs.check_source.outputs.config_hash }}
-      options: ./configure --config-cache --with-thread-sanitizer --with-pydebug
-      suppressions_path: Tools/tsan/supressions.txt
-      tsan_logs_artifact_name: tsan-logs-default
+      free-threading: ${{ matrix.free-threading }}
 
-  build_tsan_free_threading:
-    name: 'Thread sanitizer (free-threading)'
+  cross-build-linux:
+    name: Cross build Linux
+    runs-on: ubuntu-latest
     needs: check_source
     if: needs.check_source.outputs.run_tests == 'true'
-    uses: ./.github/workflows/reusable-tsan.yml
-    with:
-      config_hash: ${{ needs.check_source.outputs.config_hash }}
-      options: ./configure --config-cache --disable-gil --with-thread-sanitizer --with-pydebug
-      suppressions_path: Tools/tsan/suppressions_free_threading.txt
-      tsan_logs_artifact_name: tsan-logs-free-threading
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          persist-credentials: false
+      - name: Runner image version
+        run: echo "IMAGE_VERSION=${ImageVersion}" >> "$GITHUB_ENV"
+      - name: Restore config.cache
+        uses: actions/cache@v4
+        with:
+          path: config.cache
+          key: ${{ github.job }}-${{ runner.os }}-${{ env.IMAGE_VERSION }}-${{ needs.check_source.outputs.config_hash }}
+      - name: Register gcc problem matcher
+        run: echo "::add-matcher::.github/problem-matchers/gcc.json"
+      - name: Set build dir
+        run:
+          # an absolute path outside of the working directoy
+          echo "BUILD_DIR=$(realpath ${{ github.workspace }}/../build)" >> "$GITHUB_ENV"
+      - name: Install Dependencies
+        run: sudo ./.github/workflows/posix-deps-apt.sh
+      - name: Configure host build
+        run: ./configure --prefix="$BUILD_DIR/host-python"
+      - name: Install host Python
+        run: make -j8 install
+      - name: Run test subset with host build
+        run: |
+          "$BUILD_DIR/host-python/bin/python3" -m test test_sysconfig test_site test_embed
+      - name: Configure cross build
+        run: ./configure --prefix="$BUILD_DIR/cross-python" --with-build-python="$BUILD_DIR/host-python/bin/python3"
+      - name: Install cross Python
+        run: make -j8 install
+      - name: Run test subset with host build
+        run: |
+          "$BUILD_DIR/cross-python/bin/python3" -m test test_sysconfig test_site test_embed
 
   # CIFuzz job based on https://google.github.io/oss-fuzz/getting-started/continuous-integration/
   cifuzz:
@@ -591,7 +624,6 @@ jobs:
     - test_hypothesis
     - build_asan
     - build_tsan
-    - build_tsan_free_threading
     - cifuzz
 
     runs-on: ubuntu-latest
@@ -625,7 +657,6 @@ jobs:
             build_windows,
             build_asan,
             build_tsan,
-            build_tsan_free_threading,
             '
             || ''
           }}

.github/workflows/reusable-tsan.yml

@@ -6,17 +6,11 @@ on:
       config_hash:
         required: true
         type: string
-      options:
-        required: true
-        type: string
-      suppressions_path:
-        description: 'A repo relative path to the suppressions file'
-        required: true
-        type: string
-      tsan_logs_artifact_name:
-        description: 'Name of the TSAN logs artifact. Must be unique for each job.'
-        required: true
-        type: string
+      free-threading:
+        description: Whether to use free-threaded mode
+        required: false
+        type: boolean
+        default: false
 
 env:
   FORCE_COLOR: 1
@@ -26,9 +20,6 @@ jobs:
     name: 'Thread sanitizer'
     runs-on: ubuntu-24.04
     timeout-minutes: 60
-    env:
-      OPTIONS: ${{ inputs.options }}
-      SUPPRESSIONS_PATH: ${{ inputs.suppressions_path }}
     steps:
     - uses: actions/checkout@v4
       with:
@@ -55,7 +46,11 @@ jobs:
         sudo sysctl -w vm.mmap_rnd_bits=28
     - name: TSAN Option Setup
       run: |
-        echo "TSAN_OPTIONS=log_path=${GITHUB_WORKSPACE}/tsan_log suppressions=${GITHUB_WORKSPACE}/${SUPPRESSIONS_PATH} handle_segv=0" >> "$GITHUB_ENV"
+        echo "TSAN_OPTIONS=log_path=${GITHUB_WORKSPACE}/tsan_log suppressions=${GITHUB_WORKSPACE}/Tools/tsan/suppressions${{
+            fromJSON(inputs.free-threading)
+            && '_free_threading'
+            || ''
+          }}.txt handle_segv=0" >> "$GITHUB_ENV"
         echo "CC=clang" >> "$GITHUB_ENV"
         echo "CXX=clang++" >> "$GITHUB_ENV"
     - name: Add ccache to PATH
@@ -67,7 +62,12 @@ jobs:
         save: ${{ github.event_name == 'push' }}
         max-size: "200M"
     - name: Configure CPython
-      run: "${OPTIONS}"
+      run: >-
+        ./configure
+        --config-cache
+        --with-thread-sanitizer
+        --with-pydebug
+        ${{ fromJSON(inputs.free-threading) && '--disable-gil' || '' }}
     - name: Build CPython
       run: make -j4
     - name: Display build info
@@ -81,6 +81,11 @@ jobs:
       if: always()
       uses: actions/upload-artifact@v4
       with:
-        name: ${{ inputs.tsan_logs_artifact_name }}
+        name: >-
+          tsan-logs-${{
+            fromJSON(inputs.free-threading)
+            && 'free-threading'
+            || 'default'
+          }}
         path: tsan_log.*
         if-no-files-found: ignore

.github/workflows/reusable-windows.yml

@@ -24,7 +24,7 @@ env:
 
 jobs:
   build:
-    name: 'build and test (${{ inputs.arch }})'
+    name: ${{ inputs.arch == 'arm64' && 'build' || 'build and test' }} (${{ inputs.arch }})
     runs-on: ${{ inputs.os }}
     timeout-minutes: 60
     env:

Doc/c-api/object.rst

@@ -624,3 +624,84 @@ Object Protocol
       be immortal in another.
 
    .. versionadded:: next
+
+.. c:function:: int PyUnstable_TryIncRef(PyObject *obj)
+
+   Increments the reference count of *obj* if it is not zero.  Returns ``1``
+   if the object's reference count was successfully incremented. Otherwise,
+   this function returns ``0``.
+
+   :c:func:`PyUnstable_EnableTryIncRef` must have been called
+   earlier on *obj* or this function may spuriously return ``0`` in the
+   :term:`free threading` build.
+
+   This function is logically equivalent to the following C code, except that
+   it behaves atomically in the :term:`free threading` build::
+
+      if (Py_REFCNT(op) > 0) {
+         Py_INCREF(op);
+         return 1;
+      }
+      return 0;
+
+   This is intended as a building block for managing weak references
+   without the overhead of a Python :ref:`weak reference object <weakrefobjects>`.
+
+   Typically, correct use of this function requires support from *obj*'s
+   deallocator (:c:member:`~PyTypeObject.tp_dealloc`).
+   For example, the following sketch could be adapted to implement a
+   "weakmap" that works like a :py:class:`~weakref.WeakValueDictionary`
+   for a specific type:
+
+   .. code-block:: c
+
+      PyMutex mutex;
+
+      PyObject *
+      add_entry(weakmap_key_type *key, PyObject *value)
+      {
+          PyUnstable_EnableTryIncRef(value);
+          weakmap_type weakmap = ...;
+          PyMutex_Lock(&mutex);
+          weakmap_add_entry(weakmap, key, value);
+          PyMutex_Unlock(&mutex);
+          Py_RETURN_NONE;
+      }
+
+      PyObject *
+      get_value(weakmap_key_type *key)
+      {
+          weakmap_type weakmap = ...;
+          PyMutex_Lock(&mutex);
+          PyObject *result = weakmap_find(weakmap, key);
+          if (PyUnstable_TryIncRef(result)) {
+              // `result` is safe to use
+              PyMutex_Unlock(&mutex);
+              return result;
+          }
+          // if we get here, `result` is starting to be garbage-collected,
+          // but has not been removed from the weakmap yet
+          PyMutex_Unlock(&mutex);
+          return NULL;
+      }
+
+      // tp_dealloc function for weakmap values
+      void
+      value_dealloc(PyObject *value)
+      {
+          weakmap_type weakmap = ...;
+          PyMutex_Lock(&mutex);
+          weakmap_remove_value(weakmap, value);
+
+          ...
+          PyMutex_Unlock(&mutex);
+      }
+
+   .. versionadded:: 3.14
+
+.. c:function:: void PyUnstable_EnableTryIncRef(PyObject *obj)
+
+   Enables subsequent uses of :c:func:`PyUnstable_TryIncRef` on *obj*.  The
+   caller must hold a :term:`strong reference` to *obj* when calling this.
+
+   .. versionadded:: 3.14