run_dep_mode: treat program.args and program.env consistently

Author: RalfJung

tests/ui.rs

@@ -54,41 +54,13 @@ fn build_so_for_c_ffi_tests() -> PathBuf {
     so_file_path
 }
 
-fn test_config(target: &str, path: &str, mode: Mode, with_dependencies: bool) -> Config {
+/// Does *not* set any args or env vars, since it is shared between the test runner and
+/// run_dep_mode.
+fn miri_config(target: &str, path: &str, mode: Mode, with_dependencies: bool) -> Config {
     // Miri is rustc-like, so we create a default builder for rustc and modify it
     let mut program = CommandBuilder::rustc();
     program.program = miri_path();
 
-    // Add some flags we always want.
-    program.args.push(
-        format!(
-            "--sysroot={}",
-            env::var("MIRI_SYSROOT").expect("MIRI_SYSROOT must be set to run the ui test suite")
-        )
-        .into(),
-    );
-    program.args.push("-Dwarnings".into());
-    program.args.push("-Dunused".into());
-    program.args.push("-Ainternal_features".into());
-    if let Ok(extra_flags) = env::var("MIRIFLAGS") {
-        for flag in extra_flags.split_whitespace() {
-            program.args.push(flag.into());
-        }
-    }
-    program.args.push("-Zui-testing".into());
-    program.args.push("--target".into());
-    program.args.push(target.into());
-
-    // If we're on linux, and we're testing the extern-so functionality,
-    // then build the shared object file for testing external C function calls
-    // and push the relevant compiler flag.
-    if cfg!(target_os = "linux") && path.starts_with("tests/extern-so/") {
-        let so_file_path = build_so_for_c_ffi_tests();
-        let mut flag = std::ffi::OsString::from("-Zmiri-extern-so-file=");
-        flag.push(so_file_path.into_os_string());
-        program.args.push(flag);
-    }
-
     let mut config = Config {
         target: Some(target.to_owned()),
         stderr_filters: STDERR.clone(),
@@ -126,17 +98,45 @@ fn run_tests(
     with_dependencies: bool,
     tmpdir: &Path,
 ) -> Result<()> {
-    let mut config = test_config(target, path, mode, with_dependencies);
+    let mut config = miri_config(target, path, mode, with_dependencies);
 
     // Add a test env var to do environment communication tests.
     config.program.envs.push(("MIRI_ENV_VAR_TEST".into(), Some("0".into())));
-
     // Let the tests know where to store temp files (they might run for a different target, which can make this hard to find).
     config.program.envs.push(("MIRI_TEMP".into(), Some(tmpdir.to_owned().into())));
-
     // If a test ICEs, we want to see a backtrace.
     config.program.envs.push(("RUST_BACKTRACE".into(), Some("1".into())));
 
+    // Add some flags we always want.
+    config.program.args.push(
+        format!(
+            "--sysroot={}",
+            env::var("MIRI_SYSROOT").expect("MIRI_SYSROOT must be set to run the ui test suite")
+        )
+        .into(),
+    );
+    config.program.args.push("-Dwarnings".into());
+    config.program.args.push("-Dunused".into());
+    config.program.args.push("-Ainternal_features".into());
+    if let Ok(extra_flags) = env::var("MIRIFLAGS") {
+        for flag in extra_flags.split_whitespace() {
+            config.program.args.push(flag.into());
+        }
+    }
+    config.program.args.push("-Zui-testing".into());
+    config.program.args.push("--target".into());
+    config.program.args.push(target.into());
+
+    // If we're on linux, and we're testing the extern-so functionality,
+    // then build the shared object file for testing external C function calls
+    // and push the relevant compiler flag.
+    if cfg!(target_os = "linux") && path.starts_with("tests/extern-so/") {
+        let so_file_path = build_so_for_c_ffi_tests();
+        let mut flag = std::ffi::OsString::from("-Zmiri-extern-so-file=");
+        flag.push(so_file_path.into_os_string());
+        config.program.args.push(flag);
+    }
+
     // Handle command-line arguments.
     let args = ui_test::Args::test()?;
     let default_bless = env::var_os("RUSTC_BLESS").is_some_and(|v| v != "0");
@@ -299,13 +299,12 @@ fn main() -> Result<()> {
 
 fn run_dep_mode(target: String, mut args: impl Iterator<Item = OsString>) -> Result<()> {
     let path = args.next().expect("./miri run-dep must be followed by a file name");
-    let mut config = test_config(
+    let config = miri_config(
         &target,
         "",
         Mode::Yolo { rustfix: RustfixMode::Disabled },
         /* with dependencies */ true,
     );
-    config.program.args.clear(); // We want to give the user full control over flags
     let dep_args = config.build_dependencies()?;
 
     let mut cmd = config.program.build(&config.out_dir);