Make CLI timeout options conflict with corresponding timeout-multipli…

…er options

NEWS.md

@@ -6,6 +6,8 @@
 
 - Changed: `--timeout-multiplier` now overrides `timeout_multiplier` from `.cargo/mutants.toml`.
 
+- Changed: `--timeout` and `--timeout-multiplier` are now conflicting options.
+
 ## 24.4.0
 
 - Changes: Baselines and mutants are now built with `cargo test --no-run` rather than `cargo build --tests` as previously. This avoids wasted build effort if the `dev` and `test` Cargo profiles are not the same, and may better distinguish build failures from test failures. With `--test-tool=nextest`, the corresponding `cargo nextest run --no-run` is used.

src/main.rs

@@ -289,15 +289,15 @@ pub struct Args {
     timeout: Option<f64>,
 
     /// Test timeout multiplier (relative to base test time).
-    #[arg(long, help_heading = "Execution")]
+    #[arg(long, help_heading = "Execution", conflicts_with = "timeout")]
     timeout_multiplier: Option<f64>,
 
     /// Maximum run time for cargo build command, in seconds.
     #[arg(long, help_heading = "Execution")]
     build_timeout: Option<f64>,
 
     /// Build timeout multiplier (relative to base build time).
-    #[arg(long, help_heading = "Execution")]
+    #[arg(long, help_heading = "Execution", conflicts_with = "build_timeout")]
     build_timeout_multiplier: Option<f64>,
 
     /// Print mutations that failed to check or build.

src/options.rs

@@ -337,6 +337,26 @@ mod test {
         assert_eq!(options.build_timeout_multiplier, Some(1.0));
     }
 
+    #[test]
+    fn conflicting_timeout_options() {
+        let args = Args::try_parse_from(["mutants", "--timeout=1", "--timeout-multiplier=1"])
+            .expect_err("--timeout and --timeout-multiplier should conflict");
+        let rendered = format!("{}", args.render());
+        assert!(rendered.contains("error: the argument '--timeout <TIMEOUT>' cannot be used with '--timeout-multiplier <TIMEOUT_MULTIPLIER>'"));
+    }
+
+    #[test]
+    fn conflicting_build_timeout_options() {
+        let args = Args::try_parse_from([
+            "mutants",
+            "--build-timeout=1",
+            "--build-timeout-multiplier=1",
+        ])
+        .expect_err("--build-timeout and --build-timeout-multiplier should conflict");
+        let rendered = format!("{}", args.render());
+        assert!(rendered.contains("error: the argument '--build-timeout <BUILD_TIMEOUT>' cannot be used with '--build-timeout-multiplier <BUILD_TIMEOUT_MULTIPLIER>'"));
+    }
+
     #[test]
     fn test_tool_from_config() {
         let config = indoc! { r#"