qt_minimal: add example and CI (#1425)

* examples: enable qt_minimal for cargo without cmake

* github: add a CI runner to check qt_minimal

* qt_minimal: match target platforms directly rather than splitting

Author: ahayzen-kdab

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

@@ -129,6 +129,50 @@ jobs:
           path: ./target/debug/lcov.info
           if-no-files-found: ignore
 
+  build-qt-minimal:
+    name: Ubuntu 24.04 (gcc) Qt 6 Minimal
+    needs: [clang_format, license_check, rust_format_check, markdown_lint, shellcheck]
+    runs-on: ubuntu-24.04
+    steps:
+      - name: "Checkout repository"
+        uses: actions/checkout@v6
+      - name: Setup toolchain
+        run: |
+          rustup default 1.85.0
+          rustup component add rustfmt
+
+      - name: "Install clang-format"
+        # Note ensure that clang-format runner is updated too
+        run: |
+          pip install --user --break-system-packages --verbose clang-format==18.1.8
+          echo "Checking for path: ${{ matrix.clang_format_path }}"
+          test -x ${{ matrix.clang_format_path }}
+
+      - name: "[Ubuntu] Install dependencies"
+        if: runner.os == 'Linux'
+        run: >-
+          sudo apt-get update &&
+          sudo apt-get install -y
+          ninja-build
+          libdouble-conversion3
+          libgl1-mesa-dev
+          libssl-dev
+          libvulkan-dev
+          libxkbcommon-dev
+          pkg-config
+          valgrind
+
+      # Just test that we can build with no Qt install available
+      #
+      # NOTE: no compiler cache is needed as build is fast
+      - name: "Build"
+        run: cargo build --package qml-minimal-no-cmake
+      - name: Test output files exist
+        run: |
+          ! command -v qmake
+          test -x ./target/debug/qml-minimal-no-cmake
+          ldd ./target/debug/qml-minimal-no-cmake
+
   build-wasm:
     name: Ubuntu 24.04 (wasm_32) Qt 6
     needs: [clang_format, license_check, rust_format_check, markdown_lint, shellcheck]

Cargo.lock

@@ -25,8 +25,8 @@ sha2 = { version = "0.10.9", optional = true }
 tempfile = { version = "3.25.0", optional = true }
 tar = { version = "0.4.44", optional = true }
 flate2 = { version = "1.1.9", optional = true }
-qt-artifacts = { version = "0.1.0", optional = true }
-qt-version = { version = "0.1.3", default-features = false, optional = true }
+qt-artifacts = { version = "0.1.2", optional = true }
+qt-version = { version = "0.1.4", optional = true }
 which = { version = "8.0.0", optional = true }
 
 [features]

crates/qt-build-utils/Cargo.toml

@@ -306,26 +306,30 @@ impl QtInstallationQtMinimal {
         artifacts: Vec<ParsedQtArtifact>,
         versions: &[semver::Version],
     ) -> Vec<ParsedQtArtifact> {
-        // Arch could be x86_64
-        // OS could be linux
+        // Map from the TARGET to an arch and OS pair for the artifacts for supported Qt platforms
         // https://doc.rust-lang.org/cargo/appendix/glossary.html#target
-        //
-        // TODO: is there a better way to find the arch and os ?
-        // and should this be configurable via env var overrides?
+        // https://doc.rust-lang.org/stable/rustc/platform-support.html
+        // https://doc.qt.io/qt-6/supported-platforms.html
         println!("cargo::rerun-if-env-changed=TARGET");
-        let target = std::env::var("TARGET").expect("TARGET to be set");
-        let target_parts: Vec<_> = target.split("-").collect();
-        let arch = target_parts
-            .first()
-            .expect("TARGET to have a <arch><sub> component");
-        let os = target_parts
-            .get(2)
-            .expect("TARGET to have a <sys> component");
+        let (arch, os) = match std::env::var("TARGET").expect("TARGET to be set").as_str() {
+            // Linux
+            "aarch64-unknown-linux-gnu" => ("arm64", "linux"),
+            "x86_64-unknown-linux-gnu" => ("x86_64", "linux"),
+            // macOS
+            "aarch64-apple-darwin" => ("arm64", "macos"),
+            "x86_64-apple-darwin" => ("x86_64", "macos"),
+            // Windows
+            //
+            // NOTE: only MSVC currently, how do we map MinGW later?
+            "aarch64-pc-windows-msvc" => ("arm64", "windows"),
+            "x86_64-pc-windows-msvc" => ("x86_64", "windows"),
+            _others => panic!("Unknown TARGET to map to Qt artifact"),
+        };
 
         artifacts
             .into_iter()
             .filter(|artifact| {
-                artifact.arch == *arch && artifact.os == *os && versions.contains(&artifact.version)
+                artifact.arch == arch && artifact.os == os && versions.contains(&artifact.version)
             })
             .collect()
     }

crates/qt-build-utils/src/installation/qt_minimal/mod.rs

@@ -20,3 +20,7 @@ cxx-qt-lib = { workspace = true, features = ["full"] }
 [build-dependencies]
 # The link_qt_object_files feature is required for statically linking Qt 6.
 cxx-qt-build = { workspace = true, features = [ "link_qt_object_files" ] }
+
+# Enable qt_minimal feature in qt-build-utils and specify a qt-version
+# this allows for automatically downloading Qt when not found with qmake
+qt-build-utils = { workspace = true, features = ["qt_minimal"] }