feat: add --dry-run to install command

src/bin/cargo/commands/install.rs

@@ -16,6 +16,7 @@ use cargo_util::paths;
 pub fn cli() -> Command {
  subcommand("install")
  .about("Install a Rust binary")
+ .arg_dry_run("Perform all checks without installing (unstable)")
  .arg(
  Arg::new("crate")
  .value_name("CRATE[@<VER>]")
@@ -200,7 +201,9 @@ pub fn exec(gctx: &mut GlobalContext, args: &ArgMatches) -> CliResult {
 
  compile_opts.build_config.requested_profile =
  args.get_profile_name("release", ProfileChecking::Custom)?;
-
+ if args.dry_run() {
+ gctx.cli_unstable().fail_if_stable_opt("--dry-run", 11123)?;
+ }
  if args.flag("list") {
  ops::install_list(root, gctx)?;
  } else {
@@ -213,6 +216,7 @@ pub fn exec(gctx: &mut GlobalContext, args: &ArgMatches) -> CliResult {
  &compile_opts,
  args.flag("force"),
  args.flag("no-track"),
+ args.dry_run(),
  )?;
  }
  Ok(())

src/cargo/core/compiler/build_config.rs

@@ -31,6 +31,8 @@ pub struct BuildConfig {
  pub build_plan: bool,
  /// Output the unit graph to stdout instead of actually compiling.
  pub unit_graph: bool,
+ /// `true` to avoid really compiling.
+ pub dry_run: bool,
  /// An optional override of the rustc process for primary units
  pub primary_unit_rustc: Option<ProcessBuilder>,
  /// A thread used by `cargo fix` to receive messages on a socket regarding
@@ -112,6 +114,7 @@ impl BuildConfig {
  force_rebuild: false,
  build_plan: false,
  unit_graph: false,
+ dry_run: false,
  primary_unit_rustc: None,
  rustfix_diagnostic_server: Rc::new(RefCell::new(None)),
  export_dir: None,

src/cargo/ops/cargo_compile/mod.rs

@@ -154,6 +154,9 @@ pub fn compile_ws<'a>(
  unit_graph::emit_serialized_unit_graph(&bcx.roots, &bcx.unit_graph, ws.gctx())?;
  return Compilation::new(&bcx);
  }
+ if options.build_config.dry_run {
+ return Compilation::new(&bcx);
+ }
  crate::core::gc::auto_gc(bcx.gctx);
  let build_runner = BuildRunner::new(&bcx)?;
  build_runner.compile(exec)

src/cargo/ops/cargo_install.rs

@@ -297,7 +297,7 @@ impl<'gctx> InstallablePackage<'gctx> {
  Ok(duplicates)
  }
 
- fn install_one(mut self) -> CargoResult<bool> {
+ fn install_one(mut self, dry_run: bool) -> CargoResult<bool> {
  self.gctx.shell().status("Installing", &self.pkg)?;
 
  let dst = self.root.join("bin").into_path_unlocked();
@@ -321,6 +321,7 @@ impl<'gctx> InstallablePackage<'gctx> {
  self.check_yanked_install()?;
 
  let exec: Arc<dyn Executor> = Arc::new(DefaultExecutor);
+ self.opts.build_config.dry_run = dry_run;
  let compile = ops::compile_ws(&self.ws, &self.opts, &exec).with_context(|| {
  if let Some(td) = td_opt.take() {
  // preserve the temporary directory, so the user can inspect it
@@ -385,7 +386,7 @@ impl<'gctx> InstallablePackage<'gctx> {
  .iter()
  .filter(|t| t.is_executable())
  .collect();
- if !binaries.is_empty() {
+ if !binaries.is_empty() && !dry_run {
  self.gctx
  .shell()
  .warn(make_warning_about_missing_features(&binaries))?;
@@ -620,6 +621,7 @@ pub fn install(
  opts: &ops::CompileOptions,
  force: bool,
  no_track: bool,
+ dry_run: bool,
 ) -> CargoResult<()> {
  let root = resolve_root(root, gctx)?;
  let dst = root.join("bin").into_path_unlocked();
@@ -654,7 +656,7 @@ pub fn install(
  )?;
  let mut installed_anything = true;
  if let Some(installable_pkg) = installable_pkg {
- installed_anything = installable_pkg.install_one()?;
+ installed_anything = installable_pkg.install_one(dry_run)?;
  }
  (installed_anything, false)
  } else {
@@ -705,7 +707,7 @@ pub fn install(
 
  let install_results: Vec<_> = pkgs_to_install
  .into_iter()
- .map(|(krate, installable_pkg)| (krate, installable_pkg.install_one()))
+ .map(|(krate, installable_pkg)| (krate, installable_pkg.install_one(dry_run)))
  .collect();
 
  for (krate, result) in install_results {
@@ -745,7 +747,7 @@ pub fn install(
  let path = gctx.get_env_os("PATH").unwrap_or_default();
  let dst_in_path = env::split_paths(&path).any(|path| path == dst);
 
- if !dst_in_path {
+ if !dst_in_path && !dry_run {
  gctx.shell().warn(&format!(
  "be sure to add `{}` to your PATH to be \
  able to run the installed binaries",