Show desc of well known subcommands (fmt, clippy) in cargo --list

src/bin/cargo/cli.rs

@@ -3,12 +3,23 @@ use cargo::core::{features, CliUnstable};
 use cargo::{self, drop_print, drop_println, CliResult, Config};
 use clap::{AppSettings, Arg, ArgMatches};
 use itertools::Itertools;
+use std::collections::HashMap;
 
 use super::commands;
 use super::list_commands;
 use crate::command_prelude::*;
 use cargo::core::features::HIDDEN;
 
+lazy_static::lazy_static! {
+ // Maps from commonly known external commands (not builtin to cargo) to their
+ // description, for the help page. Reserved for external subcommands that are
+ // core within the rust ecosystem (esp ones that might become internal in the future).
+ static ref KNOWN_EXTERNAL_COMMAND_DESCRIPTIONS: HashMap<&'static str, &'static str> = vec![
+ ("clippy", "Checks a package to catch common mistakes and improve your Rust code."),
+ ("fmt", "Formats all bin and lib files of the current crate using rustfmt."),
+ ].into_iter().collect();
+}
+
 pub fn main(config: &mut Config) -> CliResult {
  // CAUTION: Be careful with using `config` until it is configured below.
  // In general, try to avoid loading config values unless necessary (like
@@ -100,14 +111,22 @@ Run with 'cargo -Z [FLAG] [SUBCOMMAND]'",
  if args.is_present("list") {
  drop_println!(config, "Installed Commands:");
  for (name, command) in list_commands(config) {
+ let known_external_desc = KNOWN_EXTERNAL_COMMAND_DESCRIPTIONS.get(name.as_str());
  match command {
  CommandInfo::BuiltIn { about } => {
+ assert!(
+ known_external_desc.is_none(),
+ "KNOWN_EXTERNAL_COMMANDS shouldn't contain builtin \"{}\"",
+ name
+ );
  let summary = about.unwrap_or_default();
  let summary = summary.lines().next().unwrap_or(&summary); // display only the first line
  drop_println!(config, " {:<20} {}", name, summary);
  }
  CommandInfo::External { path } => {
- if is_verbose {
+ if let Some(desc) = known_external_desc {
+ drop_println!(config, " {:<20} {}", name, desc);
+ } else if is_verbose {
  drop_println!(config, " {:<20} {}", name, path.display());
  } else {
  drop_println!(config, " {}", name);

tests/testsuite/cargo_command.rs

@@ -101,6 +101,31 @@ fn list_command_looks_at_path() {
  );
 }
 
+#[cargo_test]
+fn list_command_handles_known_external_commands() {
+ let p = project()
+ .executable(Path::new("path-test").join("cargo-fmt"), "")
+ .build();
+
+ let fmt_desc = " fmt Formats all bin and lib files of the current crate using rustfmt.";
+
+ // Without path - fmt isn't there
+ p.cargo("--list")
+ .env("PATH", "")
+ .with_stdout_does_not_contain(fmt_desc)
+ .run();
+
+ // With path - fmt is there with known description
+ let mut path = path();
+ path.push(p.root().join("path-test"));
+ let path = env::join_paths(path.iter()).unwrap();
+
+ p.cargo("--list")
+ .env("PATH", &path)
+ .with_stdout_contains(fmt_desc)
+ .run();
+}
+
 #[cargo_test]
 fn list_command_resolves_symlinks() {
  let proj = project()