Auto merge of rust-lang#14534 - shannmu:_cargo_installed_crates, r=epage

feat: Add custom completer for completing installed binaries

### What does this PR try to resolve?
Tracking issue rust-lang#14520

Add custom completer for `cargo uninstall <TAB>`

src/bin/cargo/commands/uninstall.rs

@@ -5,7 +5,14 @@ use cargo::ops;
 pub fn cli() -> Command {
     subcommand("uninstall")
         .about("Remove a Rust binary")
-        .arg(Arg::new("spec").value_name("SPEC").num_args(0..))
+        .arg(
+            Arg::new("spec")
+                .value_name("SPEC")
+                .num_args(0..)
+                .add::<clap_complete::ArgValueCandidates>(clap_complete::ArgValueCandidates::new(
+                    || get_installed_crates(),
+                )),
+        )
         .arg(opt("root", "Directory to uninstall packages from").value_name("DIR"))
         .arg_silent_suggestion()
         .arg_package_spec_simple("Package to uninstall")
@@ -37,3 +44,25 @@ pub fn exec(gctx: &mut GlobalContext, args: &ArgMatches) -> CliResult {
     ops::uninstall(root, specs, &values(args, "bin"), gctx)?;
     Ok(())
 }
+
+fn get_installed_crates() -> Vec<clap_complete::CompletionCandidate> {
+    get_installed_crates_().unwrap_or_default()
+}
+
+fn get_installed_crates_() -> Option<Vec<clap_complete::CompletionCandidate>> {
+    let mut candidates = Vec::new();
+
+    let gctx = GlobalContext::default().ok()?;
+
+    let root = ops::resolve_root(None, &gctx).ok()?;
+
+    let tracker = ops::InstallTracker::load(&gctx, &root).ok()?;
+
+    for (_, v) in tracker.all_installed_bins() {
+        for bin in v {
+            candidates.push(clap_complete::CompletionCandidate::new(bin));
+        }
+    }
+
+    Some(candidates)
+}

src/cargo/ops/mod.rs

@@ -22,6 +22,7 @@ pub use self::cargo_update::update_lockfile;
 pub use self::cargo_update::upgrade_manifests;
 pub use self::cargo_update::write_manifest_upgrades;
 pub use self::cargo_update::UpdateOptions;
+pub use self::common_for_install_and_uninstall::{resolve_root, InstallTracker};
 pub use self::fix::{fix, fix_exec_rustc, fix_get_proxy_lock_addr, FixOptions};
 pub use self::lockfile::{load_pkg_lockfile, resolve_to_string, write_pkg_lockfile};
 pub use self::registry::info;