Auto merge of #7486 - zachlute:suggest-alias2, r=alexcrichton

Added aliases to subcommand typo suggestions.

Fixes #7278.

Also adds tests for alias suggestions.

src/bin/cargo/main.rs

@@ -4,7 +4,7 @@
 #![warn(clippy::needless_borrow)]
 #![warn(clippy::redundant_clone)]
 
-use std::collections::BTreeSet;
+use std::collections::{BTreeMap, BTreeSet};
 use std::env;
 use std::fs;
 use std::path::{Path, PathBuf};
@@ -111,6 +111,14 @@ fn list_commands(config: &Config) -> BTreeSet<CommandInfo> {
     commands
 }
 
+/// List all runnable aliases
+fn list_aliases(config: &Config) -> Vec<String> {
+    match config.get::<BTreeMap<String, String>>("alias") {
+        Ok(aliases) => aliases.keys().map(|a| a.to_string()).collect(),
+        Err(_) => Vec::new(),
+    }
+}
+
 fn execute_external_subcommand(config: &Config, cmd: &str, args: &[&str]) -> CliResult {
     let command_exe = format!("cargo-{}{}", cmd, env::consts::EXE_SUFFIX);
     let path = search_directories(config)
@@ -120,8 +128,13 @@ fn execute_external_subcommand(config: &Config, cmd: &str, args: &[&str]) -> Cli
     let command = match path {
         Some(command) => command,
         None => {
-            let cmds = list_commands(config);
-            let did_you_mean = closest_msg(cmd, cmds.iter(), |c| c.name());
+            let commands: Vec<String> = list_commands(config)
+                .iter()
+                .map(|c| c.name().to_string())
+                .collect();
+            let aliases = list_aliases(config);
+            let suggestions = commands.iter().chain(aliases.iter());
+            let did_you_mean = closest_msg(cmd, suggestions, |c| c);
             let err = failure::format_err!("no such subcommand: `{}`{}", cmd, did_you_mean);
             return Err(CliError::new(err, 101));
         }

tests/testsuite/cargo_command.rs

@@ -168,6 +168,49 @@ error: no such subcommand: `biuld`
         .run();
 }
 
+#[cargo_test]
+fn find_closest_alias() {
+    let root = paths::root();
+    let my_home = root.join("my_home");
+    fs::create_dir(&my_home).unwrap();
+    File::create(&my_home.join("config"))
+        .unwrap()
+        .write_all(
+            br#"
+        [alias]
+        myalias = "build"
+    "#,
+        )
+        .unwrap();
+
+    cargo_process("myalais")
+        .env("CARGO_HOME", &my_home)
+        .with_status(101)
+        .with_stderr_contains(
+            "\
+error: no such subcommand: `myalais`
+
+<tab>Did you mean `myalias`?
+",
+        )
+        .run();
+
+    // But, if no alias is defined, it must not suggest one!
+    cargo_process("myalais")
+        .with_status(101)
+        .with_stderr_contains(
+            "\
+error: no such subcommand: `myalais`
+",
+        )
+        .with_stderr_does_not_contain(
+            "\
+<tab>Did you mean `myalias`?
+",
+        )
+        .run();
+}
+
 // If a subcommand is more than an edit distance of 3 away, we don't make a suggestion.
 #[cargo_test]
 fn find_closest_dont_correct_nonsense() {