Make -Dwarnings mandatory when running build-and-test

Author: GuillaumeGomez

.github/workflows/linux.yml

@@ -36,4 +36,5 @@ jobs:
         rustup target add ${{ matrix.target }}
 
     - name: Build and Test
+      env: RUSTFLAGS: -D warnings
       run: cargo run --bin ci-integration build-and-test

.github/workflows/mac.yml

@@ -32,4 +32,5 @@ jobs:
         rustup target add ${{ matrix.target }}
 
     - name: Build and Test
+      env: RUSTFLAGS: -D warnings
       run: cargo run --bin ci-integration build-and-test

.github/workflows/windows.yml

@@ -58,4 +58,5 @@ jobs:
       shell: bash
 
     - name: Build and Test
+      env: RUSTFLAGS: -D warnings
       run: cargo run --bin ci-integration build-and-test

ci/build_and_test.rs

@@ -8,6 +8,18 @@ fn run_tests_in_dir(env: &HashMap<&str, &str>, dir: &str) -> Result<(), String>
 }
 
 pub fn runner() -> Result<(), String> {
+    let Some(rustflags) = std::env::var("RUSTFLAGS") else {
+        return Err(
+            "`RUSTFLAGS` environment variable must be set to run `build-and-test`".to_string(),
+        );
+    };
+    if !rustflags.contains("-D warnings") && !rustflags.contains("-Dwarnings") {
+        return Err(
+            "`RUSTFLAGS` environment variable must contain `-Dwarnings` to run `build-and-test`"
+                .to_string(),
+        );
+    }
+
     let env = HashMap::from([("RUSTFLAGS", "-D warnings"), ("RUSTFMT_CI", "1")]);
 
     // Print version information