Add Windows CI support

.bazelrc

@@ -3,15 +3,27 @@
 # Use Bzlmod for dependency management
 common --enable_bzlmod
 
+# Auto-select platform config (linux/macos/windows)
+common --enable_platform_specific_config
+
 # Python configuration
 build --incompatible_default_to_explicit_init_py
 
 # Test output
 test --test_output=errors
 
-# C++ configuration
-build --cxxopt=-std=c++17
-build --host_cxxopt=-std=c++17
+# C++ configuration (platform-specific)
+build:linux --cxxopt=-std=c++17
+build:linux --host_cxxopt=-std=c++17
+build:macos --cxxopt=-std=c++17
+build:macos --host_cxxopt=-std=c++17
+build:windows --cxxopt=/std:c++20
+build:windows --host_cxxopt=/std:c++20
+
+# Windows: exclude Rust targets and shell-based tests
+# (rules_rust toolchain cannot build, sh_test scripts cannot execute on Windows)
+build:windows --build_tag_filters=-requires-rust,-requires-shell
+test:windows --test_tag_filters=-requires-rust,-requires-shell
 
 # Java configuration - use Java 17 for records support
 build --java_language_version=17

.github/workflows/ci.yaml

@@ -39,7 +39,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [ubuntu-latest, macos-latest]
+        os: [ubuntu-latest, macos-latest, windows-latest]
         bazel-version: ["7.x", "8.x", "9.x"]
     steps:
       - name: Checkout code
@@ -57,14 +57,18 @@ jobs:
             bazel-${{ matrix.os }}-
 
       - name: Run Bazel tests
+        shell: bash
         env:
           USE_BAZEL_VERSION: ${{ matrix.bazel-version }}
-        run: bazel test --config=ci --repository_cache="$HOME/.cache/bazel-repo" //... --test_output=errors
+        run: |
+          bazel test --config=ci --repository_cache="$HOME/.cache/bazel-repo" //... --test_output=errors
 
       - name: Build all targets
+        shell: bash
         env:
           USE_BAZEL_VERSION: ${{ matrix.bazel-version }}
-        run: bazel build --config=ci --repository_cache="$HOME/.cache/bazel-repo" //...
+        run: |
+          bazel build --config=ci --repository_cache="$HOME/.cache/bazel-repo" //...
 
   typecheck:
     name: Type Checking
@@ -87,8 +91,11 @@ jobs:
         run: bazel build --config=ci --config=typecheck --repository_cache="$HOME/.cache/bazel-repo" //...
 
   failure-tests:
-    name: Run Failure Tests
-    runs-on: ubuntu-latest
+    name: Failure Tests (${{ matrix.os }})
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, windows-latest]
     steps:
       - name: Checkout code
         uses: actions/checkout@v4
@@ -99,19 +106,22 @@ jobs:
           path: |
             ~/.cache/bazel-repo-failure
             ~/.cache/bazelisk
-          key: bazel-failure-tests-ubuntu-latest-${{ hashFiles('MODULE.bazel.lock') }}
+          key: bazel-failure-tests-${{ matrix.os }}-${{ hashFiles('MODULE.bazel.lock') }}
           restore-keys: |
-            bazel-failure-tests-ubuntu-latest-
+            bazel-failure-tests-${{ matrix.os }}-
 
       - name: Run failure tests
+        shell: bash
         run: |
+          export BAZEL_EXTRA_OPTS="--config=ci --repository_cache=$HOME/.cache/bazel-repo-failure"
           ./fire/starlark/failure_test/run_failure_tests.sh
 
   integration-test:
-    name: Integration Test (Python ${{ matrix.python-version }})
-    runs-on: ubuntu-latest
+    name: Integration Test (Python ${{ matrix.python-version }}, ${{ matrix.os }})
+    runs-on: ${{ matrix.os }}
     strategy:
       matrix:
+        os: [ubuntu-latest, windows-latest]
         python-version: ["3.10", "3.11", "3.12", "3.13"]
     steps:
       - name: Checkout code
@@ -123,12 +133,14 @@ jobs:
           path: |
             ~/.cache/bazel-repo
             ~/.cache/bazelisk
-          key: bazel-integration-py${{ matrix.python-version }}-${{ hashFiles('integration_test/MODULE.bazel.lock') }}
+          key: bazel-integration-${{ matrix.os }}-py${{ matrix.python-version }}-${{ hashFiles('integration_test/MODULE.bazel.lock') }}
           restore-keys: |
-            bazel-integration-py${{ matrix.python-version }}-
-            bazel-integration-
+            bazel-integration-${{ matrix.os }}-py${{ matrix.python-version }}-
+            bazel-integration-${{ matrix.os }}-
 
       - name: Run integration test
+        shell: bash
         run: |
+          export BAZEL_EXTRA_OPTS="--config=ci --repository_cache=$HOME/.cache/bazel-repo"
           cd integration_test
           ./run.sh --python-version ${{ matrix.python-version }}

README.md

@@ -290,3 +290,63 @@ cat bazel-bin/path/to/RELEASE_REPORT.md
 
 Use `release_readiness_test` as a CI gate — it fails the build when the report
 status is `NOT READY FOR RELEASE`.
+
+## Windows Support
+
+FIRE supports Windows with the following limitations:
+
+### Rust code generation
+
+The `rules_rust` toolchain cannot build on Windows due to an upstream linker
+issue with the process_wrapper. All Rust targets must be tagged with
+`requires-rust` so they are automatically excluded on Windows via `.bazelrc`:
+
+```starlark
+rust_library(
+    name = "my_params_rs",
+    srcs = [":my_params_rs_src"],
+    tags = ["requires-rust"],
+)
+```
+
+### Shell-based test rules
+
+`release_readiness_test` generates a shell script as its test executable, which
+Windows cannot run via `CreateProcessW`. Tag these targets with `requires-shell`
+to exclude them on Windows:
+
+```starlark
+release_readiness_test(
+    name = "release_readiness",
+    report = ":release_report",
+    tags = ["requires-shell"],
+)
+```
+
+### Platform configuration
+
+Windows exclusions are handled automatically via `.bazelrc` platform config.
+Projects consuming FIRE should include these lines in their `.bazelrc`:
+
+```text
+common --enable_platform_specific_config
+
+build:windows --build_tag_filters=-requires-rust,-requires-shell
+test:windows --test_tag_filters=-requires-rust,-requires-shell
+```
+
+### C++ standard
+
+Windows (MSVC) requires C++20 for designated initializer support. Configure
+in `.bazelrc`:
+
+```text
+build:windows --cxxopt=/std:c++20
+build:windows --host_cxxopt=/std:c++20
+```
+
+### File encoding
+
+Python scripts that read or write files containing Unicode characters (e.g.,
+`✓`, `⚠️`) must specify `encoding="utf-8"` explicitly, as Windows defaults to
+`cp1252`.