Auto merge of #14280 - Flowrey:dry-run-install, r=weihanglo

Add a `--dry-run` flag to the `install` command

### What does this PR try to resolve?

This PR add the `--dry-run` flag to the `cargo install` command (see #11123).
I've tried to do the bare minimal for this flag to work without changing anything in the output.

In my opinion, the `--dry-run` flag should mimic as close as possible the behavior of the normal command to avoid missing potential issue in the normal execution. ~~Currently we're missing information about where the binary will be installed.~~

Unlike #13598 this PR:
- Include as much of the compilation process as possible without actually compiling
- use the information provided by `BuildContext` instead of `InstallablePackage::new`
- in the same way as `unit_graph`, it add a `dry_run` to the `CompileOptions` and return a `Compilation::new` from the function `compile_ws` without actually compiling.
- keeps the output the same rather than adding  status messages indicating which very broad actions would be performed
- ~~remove some warning not relevant in the case of  a `--dry-run`~~

Like #13598, the version check and crate downloads still occur.

### How should we test and review this PR?

The first commit include a unit tests to ensure that no binary is actually installed after the dry run.
There is also a snapshot test that show the diff output of the `--help` flag.

### Additional information

Tests and documentation done in #13598, may be cherry picked into this PR if needed.

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/core/compiler/build_runner/mod.rs

@@ -126,6 +126,27 @@ impl<'a, 'gctx> BuildRunner<'a, 'gctx> {
  })
  }
 
+ /// Dry-run the compilation without actually running it.
+ ///
+ /// This is expected to collect information like the location of output artifacts.
+ /// Please keep in sync with non-compilation part in [`BuildRunner::compile`].
+ pub fn dry_run(mut self) -> CargoResult<Compilation<'gctx>> {
+ let _lock = self
+ .bcx
+ .gctx
+ .acquire_package_cache_lock(CacheLockMode::Shared)?;
+ self.lto = super::lto::generate(self.bcx)?;
+ self.prepare_units()?;
+ self.prepare()?;
+ self.check_collisions()?;
+
+ for unit in &self.bcx.roots {
+ self.collect_tests_and_executables(unit)?;
+ }
+
+ Ok(self.compilation)
+ }
+
  /// Starts compilation, waits for it to finish, and returns information
  /// about the result of compilation.
  ///
@@ -214,31 +235,7 @@ impl<'a, 'gctx> BuildRunner<'a, 'gctx> {
 
  // Collect the result of the build into `self.compilation`.
  for unit in &self.bcx.roots {
- // Collect tests and executables.
- for output in self.outputs(unit)?.iter() {
- if output.flavor == FileFlavor::DebugInfo || output.flavor == FileFlavor::Auxiliary
- {
- continue;
- }
-
- let bindst = output.bin_dst();
-
- if unit.mode == CompileMode::Test {
- self.compilation
- .tests
- .push(self.unit_output(unit, &output.path));
- } else if unit.target.is_executable() {
- self.compilation
- .binaries
- .push(self.unit_output(unit, bindst));
- } else if unit.target.is_cdylib()
- && !self.compilation.cdylibs.iter().any(|uo| uo.unit == *unit)
- {
- self.compilation
- .cdylibs
- .push(self.unit_output(unit, bindst));
- }
- }
+ self.collect_tests_and_executables(unit)?;
 
  // Collect information for `rustdoc --test`.
  if unit.mode.is_doc_test() {
@@ -307,6 +304,33 @@ impl<'a, 'gctx> BuildRunner<'a, 'gctx> {
  Ok(self.compilation)
  }
 
+ fn collect_tests_and_executables(&mut self, unit: &Unit) -> CargoResult<()> {
+ for output in self.outputs(unit)?.iter() {
+ if output.flavor == FileFlavor::DebugInfo || output.flavor == FileFlavor::Auxiliary {
+ continue;
+ }
+
+ let bindst = output.bin_dst();
+
+ if unit.mode == CompileMode::Test {
+ self.compilation
+ .tests
+ .push(self.unit_output(unit, &output.path));
+ } else if unit.target.is_executable() {
+ self.compilation
+ .binaries
+ .push(self.unit_output(unit, bindst));
+ } else if unit.target.is_cdylib()
+ && !self.compilation.cdylibs.iter().any(|uo| uo.unit == *unit)
+ {
+ self.compilation
+ .cdylibs
+ .push(self.unit_output(unit, bindst));
+ }
+ }
+ Ok(())
+ }
+
  /// Returns the executable for the specified unit (if any).
  pub fn get_executable(&mut self, unit: &Unit) -> CargoResult<Option<PathBuf>> {
  let is_binary = unit.target.is_executable();

src/cargo/ops/cargo_compile/mod.rs

@@ -156,7 +156,11 @@ pub fn compile_ws<'a>(
  }
  crate::core::gc::auto_gc(bcx.gctx);
  let build_runner = BuildRunner::new(&bcx)?;
- build_runner.compile(exec)
+ if options.build_config.dry_run {
+ build_runner.dry_run()
+ } else {
+ build_runner.compile(exec)
+ }
 }
 
 /// Executes `rustc --print <VALUE>`.

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
@@ -419,13 +420,15 @@ impl<'gctx> InstallablePackage<'gctx> {
  let staging_dir = TempFileBuilder::new()
  .prefix("cargo-install")
  .tempdir_in(&dst)?;
- for &(bin, src) in binaries.iter() {
- let dst = staging_dir.path().join(bin);
- // Try to move if `target_dir` is transient.
- if !self.source_id.is_path() && fs::rename(src, &dst).is_ok() {
- continue;
+ if !dry_run {
+ for &(bin, src) in binaries.iter() {
+ let dst = staging_dir.path().join(bin);
+ // Try to move if `target_dir` is transient.
+ if !self.source_id.is_path() && fs::rename(src, &dst).is_ok() {
+ continue;
+ }
+ paths::copy(src, &dst)?;
  }
- paths::copy(src, &dst)?;
  }
 
  let (to_replace, to_install): (Vec<&str>, Vec<&str>) = binaries
@@ -441,11 +444,13 @@ impl<'gctx> InstallablePackage<'gctx> {
  let src = staging_dir.path().join(bin);
  let dst = dst.join(bin);
  self.gctx.shell().status("Installing", dst.display())?;
- fs::rename(&src, &dst).with_context(|| {
- format!("failed to move `{}` to `{}`", src.display(), dst.display())
- })?;
- installed.bins.push(dst);
- successful_bins.insert(bin.to_string());
+ if !dry_run {
+ fs::rename(&src, &dst).with_context(|| {
+ format!("failed to move `{}` to `{}`", src.display(), dst.display())
+ })?;
+ installed.bins.push(dst);
+ successful_bins.insert(bin.to_string());
+ }
  }
 
  // Repeat for binaries which replace existing ones but don't pop the error
@@ -456,10 +461,12 @@ impl<'gctx> InstallablePackage<'gctx> {
  let src = staging_dir.path().join(bin);
  let dst = dst.join(bin);
  self.gctx.shell().status("Replacing", dst.display())?;
- fs::rename(&src, &dst).with_context(|| {
- format!("failed to move `{}` to `{}`", src.display(), dst.display())
- })?;
- successful_bins.insert(bin.to_string());
+ if !dry_run {
+ fs::rename(&src, &dst).with_context(|| {
+ format!("failed to move `{}` to `{}`", src.display(), dst.display())
+ })?;
+ successful_bins.insert(bin.to_string());
+ }
  }
  Ok(())
  };
@@ -476,9 +483,14 @@ impl<'gctx> InstallablePackage<'gctx> {
  &self.rustc.verbose_version,
  );
 
- if let Err(e) =
- remove_orphaned_bins(&self.ws, &mut tracker, &duplicates, &self.pkg, &dst)
- {
+ if let Err(e) = remove_orphaned_bins(
+ &self.ws,
+ &mut tracker,
+ &duplicates,
+ &self.pkg,
+ &dst,
+ dry_run,
+ ) {
  // Don't hard error on remove.
  self.gctx
  .shell()
@@ -515,7 +527,10 @@ impl<'gctx> InstallablePackage<'gctx> {
  }
  }
 
- if duplicates.is_empty() {
+ if dry_run {
+ self.gctx.shell().warn("aborting install due to dry run")?;
+ Ok(true)
+ } else if duplicates.is_empty() {
  self.gctx.shell().status(
  "Installed",
  format!(
@@ -620,6 +635,7 @@ 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 +670,7 @@ 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 +721,7 @@ 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 {
@@ -857,6 +873,7 @@ fn remove_orphaned_bins(
  duplicates: &BTreeMap<String, Option<PackageId>>,
  pkg: &Package,
  dst: &Path,
+ dry_run: bool,
 ) -> CargoResult<()> {
  let filter = ops::CompileFilter::new_all_targets();
  let all_self_names = exe_names(pkg, &filter);
@@ -894,8 +911,10 @@ fn remove_orphaned_bins(
  old_pkg
  ),
  )?;
- paths::remove_file(&full_path)
- .with_context(|| format!("failed to remove {:?}", full_path))?;
+ if !dry_run {
+ paths::remove_file(&full_path)
+ .with_context(|| format!("failed to remove {:?}", full_path))?;
+ }
  }
  }
  }

src/doc/man/cargo-install.md

@@ -121,6 +121,10 @@ Filesystem path to local crate to install from.
 List all installed packages and their versions.
 {{/option}}
 
+{{#option "`-n`" "`--dry-run`" }}
+(unstable) Perform all checks without installing.
+{{/option}}
+
 {{#option "`-f`" "`--force`" }}
 Force overwriting existing crates or binaries. This can be used if a package
 has installed a binary with the same name as another package. This is also

src/doc/man/generated_txt/cargo-install.txt

@@ -120,6 +120,9 @@ OPTIONS
  --list
  List all installed packages and their versions.
 
+ -n, --dry-run
+ (unstable) Perform all checks without installing.
+
  -f, --force
  Force overwriting existing crates or binaries. This can be used if a
  package has installed a binary with the same name as another

src/doc/src/commands/cargo-install.md

@@ -124,6 +124,11 @@ treated as a caret requirement like Cargo dependencies are.</dd>
 <dd class="option-desc">List all installed packages and their versions.</dd>
 
 
+<dt class="option-term" id="option-cargo-install--n"><a class="option-anchor" href="#option-cargo-install--n"></a><code>-n</code></dt>
+<dt class="option-term" id="option-cargo-install---dry-run"><a class="option-anchor" href="#option-cargo-install---dry-run"></a><code>--dry-run</code></dt>
+<dd class="option-desc">(unstable) Perform all checks without installing.</dd>
+
+
 <dt class="option-term" id="option-cargo-install--f"><a class="option-anchor" href="#option-cargo-install--f"></a><code>-f</code></dt>
 <dt class="option-term" id="option-cargo-install---force"><a class="option-anchor" href="#option-cargo-install---force"></a><code>--force</code></dt>
 <dd class="option-desc">Force overwriting existing crates or binaries. This can be used if a package

src/etc/man/cargo-install.1

@@ -151,6 +151,12 @@ Filesystem path to local crate to install from.
 List all installed packages and their versions.
 .RE
 .sp
+\fB\-n\fR, 
+\fB\-\-dry\-run\fR
+.RS 4
+(unstable) Perform all checks without installing.
+.RE
+.sp
 \fB\-f\fR, 
 \fB\-\-force\fR
 .RS 4