Handle execution of dry run commands

src/bootstrap/src/core/build_steps/test.rs

@@ -1805,7 +1805,13 @@ NOTE: if you're sure you want to do this, please open an issue as to why. In the
 
         let lldb_exe = builder.config.lldb.clone().unwrap_or_else(|| PathBuf::from("lldb"));
         let lldb_version = builder
-            .run(BootstrapCommand::new(&lldb_exe).capture().allow_failure().arg("--version"))
+            .run(
+                BootstrapCommand::new(&lldb_exe)
+                    .capture()
+                    .allow_failure()
+                    .run_always()
+                    .arg("--version"),
+            )
             .stdout_if_ok();
         if let Some(ref vers) = lldb_version {
             cmd.arg("--lldb-version").arg(vers);

src/bootstrap/src/core/metadata.rs

@@ -81,8 +81,7 @@ fn workspace_members(build: &Build) -> Vec<Package> {
             .arg("--no-deps")
             .arg("--manifest-path")
             .arg(build.src.join(manifest_path));
-        // FIXME: fix stderr
-        let metadata_output = build.run(cargo.capture()).stdout();
+        let metadata_output = build.run(cargo.capture_stdout().run_always()).stdout();
         let Output { packages, .. } = t!(serde_json::from_str(&metadata_output));
         packages
     };

src/bootstrap/src/lib.rs

@@ -964,12 +964,11 @@ impl Build {
     /// Execute a command and return its output.
     /// This method should be used for all command executions in bootstrap.
     fn run<C: AsMut<BootstrapCommand>>(&self, mut command: C) -> CommandOutput {
-        if self.config.dry_run() {
+        let command = command.as_mut();
+        if self.config.dry_run() && !command.run_always {
             return CommandOutput::default();
         }
 
-        let command = command.as_mut();
-
         self.verbose(|| println!("running: {command:?}"));
 
         let output: io::Result<Output> = match command.output_mode {

src/bootstrap/src/utils/exec.rs

@@ -47,6 +47,8 @@ pub struct BootstrapCommand {
     pub command: Command,
     pub failure_behavior: BehaviorOnFailure,
     pub output_mode: OutputMode,
+    // Run the command even during dry run
+    pub run_always: bool,
 }
 
 impl BootstrapCommand {
@@ -107,6 +109,11 @@ impl BootstrapCommand {
         Self { failure_behavior: BehaviorOnFailure::Ignore, ..self }
     }
 
+    pub fn run_always(&mut self) -> &mut Self {
+        self.run_always = true;
+        self
+    }
+
     /// Capture the output of the command, do not print it.
     pub fn capture(self) -> Self {
         Self { output_mode: OutputMode::CaptureAll, ..self }
@@ -128,7 +135,12 @@ impl AsMut<BootstrapCommand> for BootstrapCommand {
 
 impl From<Command> for BootstrapCommand {
     fn from(command: Command) -> Self {
-        Self { command, failure_behavior: BehaviorOnFailure::Exit, output_mode: OutputMode::Print }
+        Self {
+            command,
+            failure_behavior: BehaviorOnFailure::Exit,
+            output_mode: OutputMode::Print,
+            run_always: false,
+        }
     }
 }