Add native completions for --package on various commands (#16210)

### What does this PR try to resolve?

Add dynamic completions for the various `-p <package>` arguments.

Fixes #15004

```
cargo bench|build|check|doc|fix|test -p <tab>`
cargo package|publish -p <tab>
cargo add|pkgid|remove|report|run|rustc|rustdoc -p <tab>

cargo uninstall -p <tab>
cargo tree -p <tab> -i <tab>
cargo clean -p <tab> # not implemented
```

Supersedes #14553 and
#15338

---

EDIT: the second implementation has been chosen

In the first commit I implemented the different completions for
different usages by splitting the `arg_package` methods into multiple
ones if necessary:
```
     * arg_package_spec
     * arg_package_spec_no_all
     * arg_installed_package_spec_no_all <- new (for cargo uninstall)
     * arg_dependency_package_spec_no_all <- new (for cargo tree)
     * arg_clean_package_spec_simple <- new (for cargo clean)
     * arg_package_spec_simple
     * arg_package
```

In the second commit I tried to instead pass an `ArgValueCandidates`
into the function to prevent that duplication.
```
     * arg_package_spec
     * arg_package_spec_no_all (ArgValueCandidates)
     * arg_package_spec_simple (ArgValueCandidates)
     * arg_package
 ```

I think I have a small preference towards the latter, but no strong opinion.

Author: epage

src/bin/cargo/commands/clean.rs

@@ -6,14 +6,18 @@ use cargo::core::global_cache_tracker::GlobalCacheTracker;
 use cargo::ops::CleanContext;
 use cargo::ops::{self, CleanOptions};
 use cargo::util::print_available_packages;
+use clap_complete::ArgValueCandidates;
 use std::time::Duration;
 
 pub fn cli() -> Command {
     subcommand("clean")
         .about("Remove artifacts that cargo has generated in the past")
         .arg_doc("Whether or not to clean just the documentation directory")
         .arg_silent_suggestion()
-        .arg_package_spec_simple("Package to clean artifacts for")
+        .arg_package_spec_simple(
+            "Package to clean artifacts for",
+            ArgValueCandidates::new(get_pkg_name_candidates),
+        )
         .arg_release("Whether or not to clean release artifacts")
         .arg_profile("Clean artifacts of the specified profile")
         .arg_target_triple("Target triple to clean output for")

src/bin/cargo/commands/package.rs

@@ -3,6 +3,7 @@ use crate::command_prelude::*;
 use cargo::ops;
 use cargo::ops::PackageMessageFormat;
 use cargo::ops::PackageOpts;
+use clap_complete::ArgValueCandidates;
 
 pub fn cli() -> Command {
     subcommand("package")
@@ -44,6 +45,7 @@ pub fn cli() -> Command {
             "Package(s) to assemble",
             "Assemble all packages in the workspace",
             "Don't assemble specified packages",
+            ArgValueCandidates::new(get_ws_member_candidates),
         )
         .arg_features()
         .arg_target_triple("Build for the target triple")

src/bin/cargo/commands/publish.rs

@@ -2,6 +2,7 @@ use crate::command_prelude::*;
 
 use cargo::ops::{self, PublishOpts};
 use cargo_credential::Secret;
+use clap_complete::ArgValueCandidates;
 
 pub fn cli() -> Command {
     subcommand("publish")
@@ -27,6 +28,7 @@ pub fn cli() -> Command {
             "Package(s) to publish",
             "Publish all packages in the workspace",
             "Don't publish specified packages",
+            ArgValueCandidates::new(get_ws_member_candidates),
         )
         .arg_features()
         .arg_parallel()

src/bin/cargo/commands/tree.rs

@@ -7,6 +7,7 @@ use cargo::ops::Packages;
 use cargo::ops::tree::{self, DisplayDepth, EdgeKind};
 use cargo::util::CargoResult;
 use cargo::util::print_available_packages;
+use clap_complete::ArgValueCandidates;
 use std::collections::HashSet;
 use std::str::FromStr;
 
@@ -36,7 +37,10 @@ pub fn cli() -> Command {
                 "SPEC",
                 "Invert the tree direction and focus on the given package",
             )
-            .short('i'),
+            .short('i')
+            .add(clap_complete::ArgValueCandidates::new(
+                get_pkg_id_spec_candidates,
+            )),
         )
         .arg(multi_opt(
             "prune",
@@ -88,6 +92,7 @@ pub fn cli() -> Command {
             "Package to be used as the root of the tree",
             "Display the tree for all packages in the workspace",
             "Exclude specific workspace members",
+            ArgValueCandidates::new(get_pkg_id_spec_candidates),
         )
         .arg_features()
         .arg(flag("all-targets", "Deprecated, use --target=all instead").hide(true))

src/bin/cargo/commands/uninstall.rs

@@ -1,6 +1,9 @@
 use crate::command_prelude::*;
 
-use cargo::ops;
+use cargo::{CargoResult, core::PackageId, ops};
+use clap_complete::ArgValueCandidates;
+
+use std::collections::BTreeSet;
 
 pub fn cli() -> Command {
     subcommand("uninstall")
@@ -15,7 +18,10 @@ pub fn cli() -> Command {
         )
         .arg(opt("root", "Directory to uninstall packages from").value_name("DIR"))
         .arg_silent_suggestion()
-        .arg_package_spec_simple("Package to uninstall")
+        .arg_package_spec_simple(
+            "Package to uninstall",
+            ArgValueCandidates::new(get_installed_package_candidates),
+        )
         .arg(
             multi_opt("bin", "NAME", "Only uninstall the binary NAME")
                 .help_heading(heading::TARGET_SELECTION),
@@ -52,7 +58,7 @@ fn get_installed_crates() -> Vec<clap_complete::CompletionCandidate> {
 fn get_installed_crates_() -> Option<Vec<clap_complete::CompletionCandidate>> {
     let mut candidates = Vec::new();
 
-    let gctx = GlobalContext::default().ok()?;
+    let gctx = new_gctx_for_completions().ok()?;
 
     let root = ops::resolve_root(None, &gctx).ok()?;
 
@@ -66,3 +72,33 @@ fn get_installed_crates_() -> Option<Vec<clap_complete::CompletionCandidate>> {
 
     Some(candidates)
 }
+
+fn get_installed_package_candidates() -> Vec<clap_complete::CompletionCandidate> {
+    get_installed_packages()
+        .unwrap_or_default()
+        .into_iter()
+        .map(|(pkg, bins)| {
+            let single_binary = bins.iter().next().take_if(|_| bins.len() == 1);
+
+            let help = if single_binary.is_some_and(|bin| bin == pkg.name().as_str()) {
+                None
+            } else {
+                let binaries = bins.into_iter().collect::<Vec<_>>().as_slice().join(", ");
+                Some(binaries)
+            };
+
+            clap_complete::CompletionCandidate::new(pkg.name().as_str()).help(help.map(From::from))
+        })
+        .collect()
+}
+
+fn get_installed_packages() -> CargoResult<Vec<(PackageId, BTreeSet<String>)>> {
+    let gctx = new_gctx_for_completions()?;
+    let root = ops::resolve_root(None, &gctx)?;
+
+    let tracker = ops::InstallTracker::load(&gctx, &root)?;
+    Ok(tracker
+        .all_installed_bins()
+        .map(|(package_id, bins)| (*package_id, bins.clone()))
+        .collect())
+}

src/cargo/util/command_prelude.rs

@@ -23,11 +23,12 @@ use cargo_util_schemas::manifest::ProfileName;
 use cargo_util_schemas::manifest::RegistryName;
 use cargo_util_schemas::manifest::StringOrVec;
 use clap::builder::UnknownArgumentValueParser;
+use clap_complete::ArgValueCandidates;
 use home::cargo_home_with_cwd;
 use indexmap::IndexSet;
 use itertools::Itertools;
 use semver::Version;
-use std::collections::{HashMap, HashSet};
+use std::collections::{BTreeMap, HashMap, HashSet};
 use std::ffi::{OsStr, OsString};
 use std::path::Path;
 use std::path::PathBuf;
@@ -60,7 +61,13 @@ pub trait CommandExt: Sized {
         all: &'static str,
         exclude: &'static str,
     ) -> Self {
-        self.arg_package_spec_no_all(package, all, exclude)._arg(
+        self.arg_package_spec_no_all(
+            package,
+            all,
+            exclude,
+            ArgValueCandidates::new(get_ws_member_candidates),
+        )
+        ._arg(
             flag("all", "Alias for --workspace (deprecated)")
                 .help_heading(heading::PACKAGE_SELECTION),
         )
@@ -74,6 +81,7 @@ pub trait CommandExt: Sized {
         package: &'static str,
         all: &'static str,
         exclude: &'static str,
+        package_completion: ArgValueCandidates,
     ) -> Self {
         let unsupported_short_arg = {
             let value_parser = UnknownArgumentValueParser::suggest_arg("--exclude");
@@ -84,17 +92,28 @@ pub trait CommandExt: Sized {
                 .action(ArgAction::SetTrue)
                 .hide(true)
         };
-        self.arg_package_spec_simple(package)
+        self.arg_package_spec_simple(package, package_completion)
             ._arg(flag("workspace", all).help_heading(heading::PACKAGE_SELECTION))
-            ._arg(multi_opt("exclude", "SPEC", exclude).help_heading(heading::PACKAGE_SELECTION))
+            ._arg(
+                multi_opt("exclude", "SPEC", exclude)
+                    .help_heading(heading::PACKAGE_SELECTION)
+                    .add(clap_complete::ArgValueCandidates::new(
+                        get_ws_member_candidates,
+                    )),
+            )
             ._arg(unsupported_short_arg)
     }
 
-    fn arg_package_spec_simple(self, package: &'static str) -> Self {
+    fn arg_package_spec_simple(
+        self,
+        package: &'static str,
+        package_completion: ArgValueCandidates,
+    ) -> Self {
         self._arg(
             optional_multi_opt("package", "SPEC", package)
                 .short('p')
-                .help_heading(heading::PACKAGE_SELECTION),
+                .help_heading(heading::PACKAGE_SELECTION)
+                .add(package_completion),
         )
     }
 
@@ -103,7 +122,10 @@ pub trait CommandExt: Sized {
             optional_opt("package", package)
                 .short('p')
                 .value_name("SPEC")
-                .help_heading(heading::PACKAGE_SELECTION),
+                .help_heading(heading::PACKAGE_SELECTION)
+                .add(clap_complete::ArgValueCandidates::new(|| {
+                    get_ws_member_candidates()
+                })),
         )
     }
 
@@ -1313,6 +1335,29 @@ fn get_target_triples_from_rustc() -> CargoResult<Vec<clap_complete::CompletionC
         .collect())
 }
 
+pub fn get_ws_member_candidates() -> Vec<clap_complete::CompletionCandidate> {
+    get_ws_member_packages()
+        .unwrap_or_default()
+        .into_iter()
+        .map(|pkg| {
+            clap_complete::CompletionCandidate::new(pkg.name().as_str()).help(
+                pkg.manifest()
+                    .metadata()
+                    .description
+                    .to_owned()
+                    .map(From::from),
+            )
+        })
+        .collect::<Vec<_>>()
+}
+
+fn get_ws_member_packages() -> CargoResult<Vec<Package>> {
+    let gctx = new_gctx_for_completions()?;
+    let ws = Workspace::new(&find_root_manifest_for_wd(gctx.cwd())?, &gctx)?;
+    let packages = ws.members().map(Clone::clone).collect::<Vec<_>>();
+    Ok(packages)
+}
+
 pub fn get_pkg_id_spec_candidates() -> Vec<clap_complete::CompletionCandidate> {
     let mut candidates = vec![];
 
@@ -1400,6 +1445,26 @@ pub fn get_pkg_id_spec_candidates() -> Vec<clap_complete::CompletionCandidate> {
     candidates
 }
 
+pub fn get_pkg_name_candidates() -> Vec<clap_complete::CompletionCandidate> {
+    let packages: BTreeMap<_, _> = get_packages()
+        .unwrap_or_default()
+        .into_iter()
+        .map(|package| {
+            (
+                package.name(),
+                package.manifest().metadata().description.clone(),
+            )
+        })
+        .collect();
+
+    packages
+        .into_iter()
+        .map(|(name, description)| {
+            clap_complete::CompletionCandidate::new(name.as_str()).help(description.map(From::from))
+        })
+        .collect()
+}
+
 fn get_packages() -> CargoResult<Vec<Package>> {
     let gctx = new_gctx_for_completions()?;