Add ci:dry-run to skip performing builds but still test the matrix (#437)

In general, I think this will be a little niche but in the short-term
it'll be really helpful for iterating on our build matrix.

Author: zanieb

.github/workflows/apple.yml

@@ -90,6 +90,7 @@ jobs:
           path: build
 
       - name: Build
+        if: ${{ ! matrix.dry-run }}
         run: |
           if [ "${{ matrix.target_triple }}" = "aarch64-apple-darwin" ]; then
             export APPLE_SDK_PATH=/Applications/Xcode_15.2.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.2.sdk
@@ -103,18 +104,22 @@ jobs:
           ./build-macos.py --target-triple ${{ matrix.target_triple }} --python cpython-${{ matrix.python }} --options ${{ matrix.build_options }}
 
       - name: Upload Distributions
+        if: ${{ ! matrix.dry-run }}
         uses: actions/upload-artifact@v4
         with:
           name: cpython-${{ matrix.python }}-${{ matrix.target_triple }}-${{ matrix.build_options }}
           path: dist/*
 
-      - uses: actions/checkout@v4
+      - name: Checkout macOS SDKs for validation
+        if: ${{ ! matrix.dry-run }}
+        uses: actions/checkout@v4
         with:
           repository: 'phracker/MacOSX-SDKs'
           ref: master
           path: macosx-sdks
 
       - name: Validate Distribution
+        if: ${{ ! matrix.dry-run }}
         run: |
           chmod +x build/pythonbuild
 

.github/workflows/linux.yml

@@ -185,6 +185,7 @@ jobs:
           done
 
       - name: Build
+        if: ${{ ! matrix.dry-run }}
         run: |
           # Do empty target so all generated files are touched.
           ./build-linux.py --make-target empty
@@ -195,6 +196,7 @@ jobs:
           ./build-linux.py --target-triple ${{ matrix.target_triple }} --python cpython-${{ matrix.python }} --options ${{ matrix.build_options }}
 
       - name: Validate Distribution
+        if: ${{ ! matrix.dry-run }}
         run: |
           chmod +x build/pythonbuild
 
@@ -205,6 +207,7 @@ jobs:
           build/pythonbuild validate-distribution ${EXTRA_ARGS} dist/*.tar.zst
 
       - name: Upload Distribution
+        if: ${{ ! matrix.dry-run }}
         uses: actions/upload-artifact@v4
         with:
           name: cpython-${{ matrix.python }}-${{ matrix.target_triple }}-${{ matrix.build_options }}

.github/workflows/windows.yml

@@ -100,12 +100,14 @@ jobs:
           py.exe -3.9 build-windows.py --help
 
       - name: Build
+        if: ${{ ! matrix.dry-run }}
         shell: cmd
         run: |
           call "C:\Program Files\Microsoft Visual Studio\2022\Enterprise\VC\Auxiliary\Build\${{ matrix.vcvars }}"
           py.exe -3.9 build-windows.py --python cpython-${{ matrix.python }} --sh c:\cygwin\bin\sh.exe --options ${{ matrix.build_options }}
 
       - name: Validate Distribution
+        if: ${{ ! matrix.dry-run }}
         run: |
           $Dists = Resolve-Path -Path "dist/*.tar.zst" -Relative
           .\pythonbuild.exe validate-distribution --run $Dists

ci-matrix.py

@@ -14,7 +14,7 @@
 from packaging.version import Version
 
 CI_TARGETS_YAML = "ci-targets.yaml"
-CI_SKIP_LABELS = ["ci:skip", "documentation"]
+CI_EXTRA_SKIP_LABELS = ["documentation"]
 
 
 def meets_conditional_version(version: str, min_version: str) -> bool:
@@ -38,15 +38,19 @@ def parse_labels(labels: Optional[str]) -> dict[str, set[str]]:
     for label in labels.split(","):
         label = label.strip()
 
-        # Handle special directive labels
-        if label in CI_SKIP_LABELS:
+        # Handle special labels
+        if label in CI_EXTRA_SKIP_LABELS:
             result["directives"].add("skip")
             continue
 
         if not label or ":" not in label:
             continue
 
         category, value = label.split(":", 1)
+
+        if category == "ci":
+            category = "directives"
+
         if category in result:
             result[category].add(value)
 
@@ -95,6 +99,7 @@ def generate_matrix_entries(
                 target_triple,
                 target_config,
                 platform,
+                label_filters.get("directives", set()),
             )
 
     # Apply label filters if present
@@ -113,6 +118,7 @@ def add_matrix_entries_for_config(
     target_triple: str,
     config: dict[str, Any],
     platform: str,
+    directives: set[str],
 ) -> None:
     python_versions = config["python_versions"]
     build_options = config["build_options"]
@@ -135,6 +141,9 @@ def add_matrix_entries_for_config(
     if "run" in config:
         base_entry["run"] = str(config["run"]).lower()
 
+    if "dry-run" in directives:
+        base_entry["dry-run"] = "true"
+
     # Process regular build options
     for python_version in python_versions:
         for build_option in build_options: