Pin rust compiler version to 1.73 for wheel builds

With the release 1.74 on 11-16-2023 the minimum supported macOS version
by the Rust compiler is 10.12. For the 0.45.x release series we still
support macOS 10.9 (this will change in 1.0 see Qiskit#10902). To faciliate
still publishing wheels that will support macOS 10.9 for any future
bugfix releases on 0.45.x release series (and 0.46.x too) this commit
pins the rust toolchain version we use to 1.73 which is the last
release that support 10.9.

.github/workflows/wheels.yml

@@ -19,7 +19,7 @@ jobs:
         name: Install Python
         with:
           python-version: '3.10'
-      - uses: dtolnay/rust-toolchain@stable
+      - uses: dtolnay/rust-toolchain@1.73
       - name: Build wheels
         uses: pypa/cibuildwheel@v2.13.0
       - uses: actions/upload-artifact@v3
@@ -40,7 +40,7 @@ jobs:
         name: Install Python
         with:
           python-version: '3.10'
-      - uses: dtolnay/rust-toolchain@stable
+      - uses: dtolnay/rust-toolchain@1.73
       - name: Build wheels
         uses: pypa/cibuildwheel@v2.13.0
         env:
@@ -85,7 +85,7 @@ jobs:
         name: Install Python
         with:
           python-version: '3.10'
-      - uses: dtolnay/rust-toolchain@stable
+      - uses: dtolnay/rust-toolchain@1.73
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v1
         with:
@@ -118,7 +118,7 @@ jobs:
         name: Install Python
         with:
           python-version: '3.10'
-      - uses: dtolnay/rust-toolchain@stable
+      - uses: dtolnay/rust-toolchain@1.73
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v1
         with:
@@ -151,7 +151,7 @@ jobs:
         name: Install Python
         with:
           python-version: '3.10'
-      - uses: dtolnay/rust-toolchain@stable
+      - uses: dtolnay/rust-toolchain@1.73
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v1
         with:

pyproject.toml

@@ -17,11 +17,11 @@ test-command = "python {project}/examples/python/stochastic_swap.py"
 # Numpy 1.22 there are no i686 wheels, so we force pip to use older ones without
 # restricting any dependencies that Numpy and Scipy might have.
 before-test = "pip install --only-binary=numpy,scipy numpy scipy"
-environment = 'RUSTUP_TOOLCHAIN="stable"'
+environment = 'RUSTUP_TOOLCHAIN="1.73"'
 
 [tool.cibuildwheel.linux]
 before-all = "yum install -y wget && {package}/tools/install_rust.sh"
-environment = 'PATH="$PATH:$HOME/.cargo/bin" CARGO_NET_GIT_FETCH_WITH_CLI="true" RUSTUP_TOOLCHAIN="stable"'
+environment = 'PATH="$PATH:$HOME/.cargo/bin" CARGO_NET_GIT_FETCH_WITH_CLI="true" RUSTUP_TOOLCHAIN="1.73"'
 repair-wheel-command = "auditwheel repair -w {dest_dir} {wheel} && pipx run abi3audit --strict --report {wheel}"
 
 [tool.cibuildwheel.macos]

tools/install_rust.sh

@@ -2,5 +2,5 @@
 if [ ! -d rust-installer ]; then
     mkdir rust-installer
     wget https://sh.rustup.rs -O rust-installer/rustup.sh
-    sh rust-installer/rustup.sh -y
+    sh rust-installer/rustup.sh -y --default-toolchain 1.73
 fi