ci: set the CARGO_BUILD_TARGET to reuse same cache

.github/workflows/github-cxx-qt-tests.yml

@@ -269,6 +269,7 @@ jobs:
             clang_format_path: /home/runner/.local/bin/clang-format
             cargo_dir: ~/.cargo
             rustc_wrapper: sccache
+            cargo_target: x86_64-unknown-linux-gnu
           - name: Ubuntu 24.04 (gcc) Qt6
             os: ubuntu-24.04
             qt_version: 6
@@ -289,6 +290,7 @@ jobs:
                 libgl1-mesa-dev
                 libvulkan-dev
                 libxkbcommon-dev
+            cargo_target: x86_64-unknown-linux-gnu
 
           - name: macOS 13 (clang) Qt5
             os: macos-13
@@ -311,6 +313,7 @@ jobs:
             cc: clang
             cxx: clang++
             rustc_wrapper: sccache
+            cargo_target: x86_64-apple-darwin
           - name: macOS 14 (clang) Qt6
             os: macos-14
             qt_version: 6
@@ -332,6 +335,7 @@ jobs:
             cc: clang
             cxx: clang++
             rustc_wrapper: sccache
+            cargo_target: aarch64-apple-darwin
 
           - name: Windows 2022 (MSVC) Qt5
             os: windows-2022
@@ -350,6 +354,7 @@ jobs:
             cc: cl
             cxx: cl
             rustc_wrapper: sccache
+            cargo_target: x86_64-pc-windows-msvc
           - name: Windows 2022 (MSVC2019) Qt6
             os: windows-2022
             qt_version: 6
@@ -367,6 +372,7 @@ jobs:
             cc: cl
             cxx: cl
             rustc_wrapper: sccache
+            cargo_target: x86_64-pc-windows-msvc
           - name: Windows 2022 (MSVC2022) Qt6
             os: windows-2022
             qt_version: 6
@@ -384,6 +390,7 @@ jobs:
             cc: cl
             cxx: cl
             rustc_wrapper: sccache
+            cargo_target: x86_64-pc-windows-msvc
 
     runs-on: ${{ matrix.os }}
     name: ${{ matrix.name }}
@@ -397,6 +404,8 @@ jobs:
         SCCACHE_CACHE_SIZE: 600M
         SCCACHE_LOG: debug
         SCCACHE_ERROR_LOG: ${{ matrix.sccache_log_path }}
+        # Ensure that we share the same target sub folder
+        CARGO_BUILD_TARGET: ${{ matrix.cargo_target }}
 
     steps:
     - name: "Clone Git repository"

CMakeLists.txt

@@ -149,16 +149,18 @@ set(CARGO_TARGET_DIR "${CMAKE_BINARY_DIR}/${BUILD_DIR}/cargo/build")
 
 if(BUILD_TESTING)
     # Add CMake tests for `cargo test/clippy/fmt/doc`.
-    add_test(NAME cargo_tests COMMAND cargo test --release --all-features --target-dir ${CARGO_TARGET_DIR})
-    add_test(NAME cargo_doc COMMAND cargo doc --release --all-features --target-dir ${CARGO_TARGET_DIR})
+    add_test(NAME cargo_tests COMMAND cargo test --locked --release --all-features --target-dir ${CARGO_TARGET_DIR})
+    add_test(NAME cargo_doc COMMAND cargo doc --locked --release --all-features --target-dir ${CARGO_TARGET_DIR})
     # Minimum clippy version for the incompatible_msrv lint is 1.78.0
-    add_test(NAME cargo_clippy COMMAND cargo +1.78.0 clippy --release --all-features --target-dir ${CARGO_TARGET_DIR} -- -D warnings)
+    add_test(NAME cargo_clippy COMMAND cargo +1.78.0 clippy --locked --release --all-features --target-dir ${CARGO_TARGET_DIR} -- -D warnings)
 
     set_tests_properties(cargo_tests cargo_clippy PROPERTIES
         ENVIRONMENT_MODIFICATION "${CARGO_ENV}"
     )
+    # Cargo doc cannot have a target set otherwise it fails
+    # https://github.com/rust-lang/cargo/issues/10368
     set_tests_properties(cargo_doc PROPERTIES
-        ENVIRONMENT_MODIFICATION "${CARGO_ENV};RUSTDOCFLAGS=set:--deny=warnings"
+        ENVIRONMENT_MODIFICATION "${CARGO_ENV};RUSTDOCFLAGS=set:--deny=warnings;CARGO_BUILD_TARGET=unset:;"
     )
 
     # Ensure test inputs and outputs are formatted
@@ -168,7 +170,7 @@ if(BUILD_TESTING)
     add_test(NAME cxx_qt_gen_test_outputs_gen COMMAND rustfmt --check ${CXX_QT_GEN_TEST_OUTPUTS})
 
     # Add test which checks that a build rerun doesn't recompile and uses caches instead
-    add_test(NAME cargo_build_rerun COMMAND "${CMAKE_CURRENT_SOURCE_DIR}/scripts/check_cargo_build_rerun.sh" "${CMAKE_CURRENT_SOURCE_DIR}")
+    add_test(NAME cargo_build_rerun COMMAND "${CMAKE_CURRENT_SOURCE_DIR}/scripts/check_cargo_build_rerun.sh" "${CMAKE_CURRENT_SOURCE_DIR}" "${CARGO_TARGET_DIR}")
 
     # Ensure that cargo_build_rerun doesn't run while we are already building
     set_tests_properties(cargo_build_rerun PROPERTIES RUN_SERIAL TRUE)

scripts/check_cargo_build_rerun.sh

@@ -7,15 +7,16 @@
 
 set -ex
 
+SOURCE_FOLDER=$1
+BUILD_FOLDER=$2
+
 # Ensure we are in the right directory
-SCRIPT=$(realpath "$0")
-SCRIPTPATH=$(dirname "$SCRIPT")
-cd "$SCRIPTPATH/../"
+cd "$SOURCE_FOLDER"
 
 # Ensure that we do see a "Compiling" in the output
 # as if we do it means we have a cargo::rerun-if-changed incorrectly
 function check_build_contains_compiling() {
-    BUILD=$(cargo build -p qml-minimal-no-cmake 2>&1)
+    BUILD=$(cargo build --locked --release --target-dir="$BUILD_FOLDER" -p qml-minimal-no-cmake 2>&1)
 
     if ! echo "$BUILD" | grep -q Compiling; then
         echo "cargo build is missing text 'Compiling', likely an incorrect cargo::rerun-if-changed in a build script."
@@ -26,7 +27,7 @@ function check_build_contains_compiling() {
 # Ensure that we don't see any "Compiling" in the output
 # as if we do it means we have a cargo::rerun-if-changed incorrectly
 function check_build_no_compiling() {
-    BUILD=$(cargo build -p qml-minimal-no-cmake 2>&1)
+    BUILD=$(cargo build --locked --release --target-dir="$BUILD_FOLDER" -p qml-minimal-no-cmake 2>&1)
 
     if echo "$BUILD" | grep -q Compiling; then
         echo "cargo build contained text 'Compiling', likely an incorrect cargo::rerun-if-changed in a build script."
@@ -35,20 +36,20 @@ function check_build_no_compiling() {
 }
 
 # Build once
-cargo build -p qml-minimal-no-cmake
+cargo build --locked --release --target-dir="$BUILD_FOLDER" -p qml-minimal-no-cmake
 
 # Build a second time
 check_build_no_compiling
 
 # Modify a qml file
-touch "$SCRIPTPATH/../examples/cargo_without_cmake/qml/main.qml"
+touch "$SOURCE_FOLDER/examples/cargo_without_cmake/qml/main.qml"
 
 # Build a third and fourth time
 check_build_contains_compiling
 check_build_no_compiling
 
 # Modify a Rust file
-touch "$SCRIPTPATH/../examples/cargo_without_cmake/src/cxxqt_object.rs"
+touch "$SOURCE_FOLDER/examples/cargo_without_cmake/src/cxxqt_object.rs"
 
 # Build a fifth and sixth time
 check_build_contains_compiling