Sync upstream tag 20260504

.github/workflows/linux.yml

@@ -178,6 +178,7 @@ jobs:
             --platform linux \
             --labels "${STEPS_GET_LABELS_OUTPUTS_LABELS}" \
             --max-shards 2 \
+            --event ${{ github.event_name }} \
             ${{ (steps.check-pythonbuild.outputs.changed == 'true' || github.ref == 'refs/heads/main') && '--force-crate-build' || '' }} \
             --free-runners \
             > matrix.json

.github/workflows/macos.yml

@@ -92,7 +92,11 @@ jobs:
       - name: Generate build matrix
         id: set-matrix
         run: |
+<<<<<<< HEAD
           uv run ci-matrix.py --platform darwin --labels "${STEPS_GET_LABELS_OUTPUTS_LABELS}" ${{ (steps.check-pythonbuild.outputs.changed == 'true' || github.ref == 'refs/heads/main') && '--force-crate-build' || '' }} --free-runners > matrix.json
+=======
+          uv run ci-matrix.py --platform darwin --labels "${STEPS_GET_LABELS_OUTPUTS_LABELS}" --event ${{ github.event_name }} ${{ (steps.check-pythonbuild.outputs.changed == 'true' || github.ref == 'refs/heads/main') && '--force-crate-build' || '' }} > matrix.json
+>>>>>>> refs/tags/20260504
 
           # Extract python-build matrix
           echo "matrix=$(jq -c '."python-build"' matrix.json)" >> $GITHUB_OUTPUT

.github/workflows/windows.yml

@@ -92,7 +92,11 @@ jobs:
       - name: Generate build matrix
         id: set-matrix
         run: |
+<<<<<<< HEAD
           uv run ci-matrix.py --platform windows --labels "${STEPS_GET_LABELS_OUTPUTS_LABELS}" ${{ (steps.check-pythonbuild.outputs.changed == 'true' || github.ref == 'refs/heads/main') && '--force-crate-build' || '' }} --free-runners > matrix.json
+=======
+          uv run ci-matrix.py --platform windows --labels "${STEPS_GET_LABELS_OUTPUTS_LABELS}" --event ${{ github.event_name }} ${{ (steps.check-pythonbuild.outputs.changed == 'true' || github.ref == 'refs/heads/main') && '--force-crate-build' || '' }} > matrix.json
+>>>>>>> refs/tags/20260504
 
           # Extract python-build matrix
           echo "matrix=$(jq -c '."python-build"' matrix.json)" >> $GITHUB_OUTPUT

CONTRIBUTING.rst

@@ -8,28 +8,41 @@ Building distributions
 See the [documentation](https://gregoryszorc.com/docs/python-build-standalone/main/building.html)
 for instructions on building distributions locally.
 
-CI labels
-=========
-By default, submitting a pull request triggers a complete build of all
-distributions in CI, which can be time-consuming.
+Pull request labels
+===================
+By default, pull requests build a small subset of targets defined in
+``ci-defaults.yaml`` under ``pull_request``. Pushes to ``main`` build the full
+matrix from ``ci-targets.yaml``.
 
-To conserve CI resources and reduce build times, you can limit the matrix of
-distributions built by applying specific labels to your pull request. Only
-distributions matching the specified labels will be built.
+Pull request labels can be used to change what CI builds:
 
-The following label prefixes can be used to customize the build matrix:
+* ``platform:<value>`` filters the selected targets by platform.
+* ``arch:<value>`` filters the selected targets by architecture.
+* ``libc:<value>`` filters the selected targets by libc.
+* ``python:<value>`` filters the selected Python versions.
+* ``build:<value>`` filters the selected build options by component.
 
-* `platform`
-* `python`
-* `build`
-* `arch`
-* `libc`
+The ``:all`` labels expand only their own dimension:
 
-To bypass CI entirely for changes that do not affect the build (such as
-documentation updates), use the `ci:skip` label.
+* ``platform:all`` expands the selected platforms.
+* ``arch:all`` expands the selected architectures.
+* ``libc:all`` expands the selected libc variants.
+* ``python:all`` expands the selected Python versions.
+* ``build:all`` expands the selected build options.
 
-Please utilize these tags when appropriate for your changes to minimize CI
-resource consumption.
+Use ``ci:all-targets`` to build the full matrix from ``ci-targets.yaml``.
+
+Examples:
+
+* ``platform:linux`` builds only the Linux targets from ``ci-defaults.yaml``.
+* ``python:3.13`` builds the default targets with Python 3.13.
+* ``build:pgo`` builds the selected targets whose build options include ``pgo``.
+* ``platform:linux,arch:all,libc:all,python:all,build:all`` builds the full
+  Linux matrix.
+
+To bypass CI entirely for changes that do not affect the build, use the
+``ci:skip`` label. The ``documentation`` label is treated the same way. To run
+a dry-run build matrix, use ``ci:dry-run``.
 
 Releases
 ========

ci-defaults.yaml

@@ -0,0 +1,28 @@
+# Describes the default targets that CI will build for different events.
+
+pull_request:
+  python_version: "3.14"
+
+  targets:
+    x86_64-pc-windows-msvc:
+      build_options:
+        - pgo
+
+    aarch64-apple-darwin:
+      build_options:
+        - pgo+lto
+
+    x86_64-unknown-linux-gnu:
+      build_options:
+        - pgo+lto
+        - freethreaded+pgo+lto
+
+    x86_64-unknown-linux-musl:
+      build_options:
+        - lto
+        - lto+static
+        - freethreaded+lto
+
+    armv7-unknown-linux-gnueabihf:
+      build_options:
+        - lto