feat: add --dry-run to install command

Author: Flowrey

src/bin/cargo/commands/install.rs

@@ -69,6 +69,7 @@ pub fn cli() -> Command {
         )
         .arg(opt("root", "Directory to install packages into").value_name("DIR"))
         .arg(flag("force", "Force overwriting existing crates or binaries").short('f'))
+        .arg_dry_run("Perform all checks without installing (unstable)")
         .arg(flag("no-track", "Do not save tracking information"))
         .arg(flag(
             "list",
@@ -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",

tests/testsuite/cargo_install/help/stdout.term.svg

@@ -2735,19 +2735,15 @@ fn uninstall_running_binary() {
 fn dry_run() {
     pkg("foo", "0.0.1");
 
-    cargo_process("install foo")
+    cargo_process("-Z unstable-options install --dry-run foo")
+        .masquerade_as_nightly_cargo(&["install::dry-run"])
         .with_stderr_data(str![[r#"
 [UPDATING] `dummy-registry` index
 [DOWNLOADING] crates ...
 [DOWNLOADED] foo v0.0.1 (registry `dummy-registry`)
 [INSTALLING] foo v0.0.1
-[COMPILING] foo v0.0.1
-[FINISHED] `release` profile [optimized] target(s) in [ELAPSED]s
-[INSTALLING] [ROOT]/home/.cargo/bin/foo[EXE]
-[INSTALLED] package `foo v0.0.1` (executable `foo[EXE]`)
-[WARNING] be sure to add `[ROOT]/home/.cargo/bin` to your PATH to be able to run the installed binaries
 
 "#]])
         .run();
-    assert_has_installed_exe(paths::cargo_home(), "foo");
+    assert_has_not_installed_exe(paths::cargo_home(), "foo");
 }