chore(ci): add MSRV build to check we are compliant with what we announce

- have to downgrade param_dedup edition as 1.84 cannot handle 2024 in a
workspace

.github/workflows/cargo_build.yml

@@ -59,6 +59,11 @@ jobs:
         run: |
           make build_tfhe_csprng
 
+      - name: Build with MSRV
+        if: ${{ contains(matrix.os, 'ubuntu') }}
+        run: |
+          make build_tfhe_msrv
+
       - name: Build Release core
         if: ${{ contains(matrix.os, 'ubuntu') }}
         run: |

Makefile

@@ -96,6 +96,12 @@ install_rs_build_toolchain:
 	( echo "Unable to install $(RS_BUILD_TOOLCHAIN) toolchain, check your rustup installation. \
 	Rustup can be downloaded at https://rustup.rs/" && exit 1 )
 
+.PHONY: install_rs_msrv_toolchain # Install the msrv toolchain
+install_rs_msrv_toolchain:
+	@rustup toolchain install --profile default "$(MIN_RUST_VERSION)" || \
+	( echo "Unable to install $(MIN_RUST_VERSION) toolchain, check your rustup installation. \
+	Rustup can be downloaded at https://rustup.rs/" && exit 1 )
+
 .PHONY: install_build_wasm32_target # Install the wasm32 toolchain used for builds
 install_build_wasm32_target: install_rs_build_toolchain
 	rustup +$(RS_BUILD_TOOLCHAIN) target add wasm32-unknown-unknown || \
@@ -581,6 +587,15 @@ build_tfhe_coverage: install_rs_build_toolchain
 	RUSTFLAGS="$(RUSTFLAGS) --cfg tarpaulin" cargo $(CARGO_RS_BUILD_TOOLCHAIN) build --profile $(CARGO_PROFILE) \
 		--features=boolean,shortint,integer,internal-keycache -p tfhe --tests
 
+# As of 05/08/2025 this is the set of features that can be easily compiled without additional
+# toolkits
+.PHONY: build_tfhe_msrv # Build with msrv compiler
+build_tfhe_msrv: install_rs_build_toolchain
+	RUSTFLAGS="$(RUSTFLAGS)" cargo +$(MIN_RUST_VERSION) build --profile dev \
+		--features=boolean,extended-types,hpu,hpu-debug \
+		--features=hpu-v80,integer,noise-asserts \
+		--features=pbs-stats,shortint,strings,zk-pok -p tfhe
+
 .PHONY: build_c_api # Build the C API for boolean, shortint and integer
 build_c_api: install_rs_check_toolchain
 	RUSTFLAGS="$(RUSTFLAGS)" cargo $(CARGO_RS_CHECK_TOOLCHAIN) build --profile $(CARGO_PROFILE) \

utils/param_dedup/Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "param_dedup"
 version = "0.1.0"
-edition = "2024"
+edition = "2021"
 publish = false
 
 [dependencies]