ci: Prepare for addition of non-additive features

See #94 for the context.

.github/workflows/ci.yml

@@ -23,6 +23,10 @@ env:
   RUSTDOCFLAGS: -D warnings
   RUSTFLAGS: -D warnings
   RUSTUP_MAX_RETRIES: 10
+  # NB: sync with:
+  # - docs.rs metadata in Cargo.toml
+  # - test_features list in tools/build.sh and tools/test.sh.
+  TEST_FEATURES: float,std,serde,critical-section
 
 defaults:
   run:
@@ -47,7 +51,7 @@ jobs:
     with:
       event_name: ${{ github.event_name }}
       # Exclude serde and critical-section features because the MSRV when it is enabled depends on the MSRV of them
-      args: -vvv --feature-powerset --depth 2 --optional-deps --exclude-features serde,critical-section
+      args: -vvv --feature-powerset --depth 2 --optional-deps --exclude-features serde,critical-section,__do_not_enable
   tidy:
     uses: taiki-e/workflows/.github/workflows/tidy.yml@main
     with:
@@ -299,7 +303,7 @@ jobs:
       - run: tools/build.sh ${{ matrix.target || 'host' }}
       - run: TESTS=1 tools/build.sh ${{ matrix.target || 'host' }}
 
-      - run: cargo minimal-versions build -vvv --workspace --all-features --ignore-private $TARGET $BUILD_STD
+      - run: cargo minimal-versions build -vvv --workspace --features $TEST_FEATURES --ignore-unknown-features --ignore-private $TARGET $BUILD_STD
         if: matrix.rust != '1.54'
 
   build:

Cargo.toml

@@ -13,7 +13,10 @@ Portable atomic types including support for 128-bit atomics, atomic float, etc.
 """
 
 [package.metadata.docs.rs]
-features = ["float", "std", "serde"]
+# NB: sync with:
+# - env.TEST_FEATURES in .github/workflows/ci.yml.
+# - test_features list in tools/build.sh and tools/test.sh.
+features = ["float", "std", "serde", "critical-section"]
 rustdoc-args = ["--cfg", "docsrs"]
 targets = ["x86_64-unknown-linux-gnu"]
 
@@ -50,6 +53,10 @@ std = []
 # See documentation for more: https://github.com/taiki-e/portable-atomic#optional-features-require-cas
 require-cas = []
 
+# DO NOT USE. This is NOT public API. Only used for testing our test infrastructures.
+# TODO: remove when adding real non-additive features.
+__do_not_enable = []
+
 # Note: serde and critical-section are public dependencies.
 [dependencies]
 # Implements serde::{Serialize,Deserialize} for atomic types.

portable-atomic-util/.external-types.toml

@@ -0,0 +1,6 @@
+# cargo-check-external-types configuration
+# https://crates.io/crates/cargo-check-external-types
+
+# The following are external types that are allowed to be exposed in our public API.
+allowed_external_types = [
+]

src/lib.rs

@@ -419,6 +419,9 @@ compile_error!(
     "you may not enable feature `critical-section` and cfg(portable_atomic_unsafe_assume_single_core) at the same time"
 );
 
+#[cfg(feature = "__do_not_enable")]
+compile_error!("Do NOT use `__do_not_enable` feature. This is NOT public API. Only used for testing our test infrastructures.");
+
 #[cfg(feature = "require-cas")]
 #[cfg_attr(
     portable_atomic_no_cfg_target_has_atomic,

tools/build.sh

@@ -120,6 +120,12 @@ known_cfgs=(
     rustfmt
     valgrind
 )
+# NB: sync with:
+# - docs.rs metadata in Cargo.toml
+# - env.TEST_FEATURES in .github/workflows/ci.yml.
+# - test_features list in tools/test.sh.
+test_features="float,std,serde,critical-section"
+exclude_features="__do_not_enable"
 
 x() {
     local cmd="$1"
@@ -381,7 +387,8 @@ build() {
             return 0
         fi
         args+=(
-            --all-features --tests
+            --tests
+            --features "${test_features}"
             --workspace --exclude bench --exclude portable-atomic-internal-codegen
         )
     elif [[ -n "${TARGET_GROUP:-}" ]]; then
@@ -451,6 +458,7 @@ build() {
 
         args+=(
             --feature-powerset --depth 2 --optional-deps --no-dev-deps
+            ${exclude_features+"--exclude-features=${exclude_features}"}
             --workspace --ignore-private
         )
         # critical-section requires 1.54

tools/test.sh

@@ -11,6 +11,12 @@ trap -- 'echo >&2 "$0: trapped SIGINT"; exit 1' SIGINT
 #    ./tools/test.sh [+toolchain] [cargo_options]...
 #    ./tools/test.sh [+toolchain] build|miri|valgrind [cargo_options]...
 
+# NB: sync with:
+# - docs.rs metadata in Cargo.toml
+# - env.TEST_FEATURES in .github/workflows/ci.yml.
+# - test_features list in tools/build.sh.
+test_features="float,std,serde,critical-section"
+
 x() {
     local cmd="$1"
     shift
@@ -136,7 +142,7 @@ if [[ -n "${target}" ]]; then
         fi
     fi
 fi
-args+=(--all-features)
+args+=(--features "${test_features}")
 case "${cmd}" in
     build) ;;
     *) args+=(--workspace --exclude bench --exclude portable-atomic-internal-codegen) ;;