feat(help): Add styling to help output

Traditionally, cargo has disabled clap's styled output.  My assumed
reason is that cargo mixes custom help output with auto-generated and
you couldn't previously make it all styled.

Clap 4.2 allowed users to pass in strings styled using ANSI escape
codes, allowing us to pass in styled text that matches clap.  In clap
4.4.1, clap gained the ability for the user to override the style.

In this PR, I decided to use the new 4.4.1 feature to style clap's
output to match the rest of cargo's output.  Alternatively, we could use
a more subdue style that clap uses by default.

Author: epage

Cargo.lock

@@ -30,6 +30,7 @@ cargo-test-support = { path = "crates/cargo-test-support" }
 cargo-util = { version = "0.2.6", path = "crates/cargo-util" }
 cargo_metadata = "0.14.0"
 clap = "4.4.1"
+color-print = "0.3.4"
 core-foundation = { version = "0.9.3", features = ["mac_os_10_7_support"] }
 crates-io = { version = "0.39.0", path = "crates/crates-io" }
 criterion = { version = "0.5.1", features = ["html_reports"] }
@@ -130,6 +131,7 @@ cargo-credential-libsecret.workspace = true
 cargo-credential-macos-keychain.workspace = true
 cargo-credential-wincred.workspace = true
 cargo-util.workspace = true
+color-print.workspace = true
 clap = { workspace = true, features = ["wrap_help"] }
 crates-io.workspace = true
 curl = { workspace = true, features = ["http2"] }

Cargo.toml

@@ -520,48 +520,59 @@ pub fn cli() -> Command {
     } else {
         "cargo [OPTIONS] [COMMAND]\n       cargo [OPTIONS] -Zscript <MANIFEST_RS> [ARGS]..."
     };
+
+    let styles = {
+        use clap::builder::styling::*;
+        Styles::styled()
+            .header(AnsiColor::Green.on_default() | Effects::BOLD)
+            .usage(AnsiColor::Green.on_default() | Effects::BOLD)
+            .literal(AnsiColor::Blue.on_default() | Effects::BOLD)
+            .placeholder(AnsiColor::Cyan.on_default())
+            .error(AnsiColor::Red.on_default())
+            .valid(AnsiColor::Blue.on_default() | Effects::BOLD)
+            .invalid(AnsiColor::Yellow.on_default())
+    };
+
     Command::new("cargo")
         // Subcommands all count their args' display order independently (from 0),
         // which makes their args interspersed with global args. This puts global args last.
         //
         // We also want these to come before auto-generated `--help`
         .next_display_order(800)
         .allow_external_subcommands(true)
-        // Doesn't mix well with our list of common cargo commands.  See clap-rs/clap#3108 for
-        // opening clap up to allow us to style our help template
-        .disable_colored_help(true)
+        .styles(styles)
         // Provide a custom help subcommand for calling into man pages
         .disable_help_subcommand(true)
         .override_usage(usage)
-        .help_template(
+        .help_template(color_print::cstr!(
             "\
 Rust's package manager
 
-Usage: {usage}
+<green,bold>Usage:</> <blue,bold>{usage}</>
 
-Options:
+<green,bold>Options:</>
 {options}
 
-Some common cargo commands are (see all commands with --list):
-    build, b    Compile the current package
-    check, c    Analyze the current package and report errors, but don't build object files
-    clean       Remove the target directory
-    doc, d      Build this package's and its dependencies' documentation
-    new         Create a new cargo package
-    init        Create a new cargo package in an existing directory
-    add         Add dependencies to a manifest file
-    remove      Remove dependencies from a manifest file
-    run, r      Run a binary or example of the local package
-    test, t     Run the tests
-    bench       Run the benchmarks
-    update      Update dependencies listed in Cargo.lock
-    search      Search registry for crates
-    publish     Package and upload this package to the registry
-    install     Install a Rust binary. Default location is $HOME/.cargo/bin
-    uninstall   Uninstall a Rust binary
-
-See 'cargo help <command>' for more information on a specific command.\n",
-        )
+Some common cargo commands are (see all commands with '<blue,bold>--list</>'):
+    <blue,bold>build</>, <blue,bold>b</>    Compile the current package
+    <blue,bold>check</>, <blue,bold>c</>    Analyze the current package and report errors, but don't build object files
+    <blue,bold>clean</>       Remove the target directory
+    <blue,bold>doc</>, <blue,bold>d</>      Build this package's and its dependencies' documentation
+    <blue,bold>new</>         Create a new cargo package
+    <blue,bold>init</>        Create a new cargo package in an existing directory
+    <blue,bold>add</>         Add dependencies to a manifest file
+    <blue,bold>remove</>      Remove dependencies from a manifest file
+    <blue,bold>run</>, <blue,bold>r</>      Run a binary or example of the local package
+    <blue,bold>test</>, <blue,bold>t</>     Run the tests
+    <blue,bold>bench</>       Run the benchmarks
+    <blue,bold>update</>      Update dependencies listed in Cargo.lock
+    <blue,bold>search</>      Search registry for crates
+    <blue,bold>publish</>     Package and upload this package to the registry
+    <blue,bold>install</>     Install a Rust binary. Default location is $HOME/.cargo/bin
+    <blue,bold>uninstall</>   Uninstall a Rust binary
+
+See '<blue,bold>cargo help <<command>></>' for more information on a specific command.\n",
+        ))
         .arg(flag("version", "Print version info and exit").short('V'))
         .arg(flag("list", "List installed commands"))
         .arg(opt("explain", "Run `rustc --explain CODE`").value_name("CODE"))

src/bin/cargo/cli.rs

@@ -38,7 +38,9 @@ pub fn cli() -> Command {
         .arg_manifest_path()
         .arg_unit_graph()
         .arg_timings()
-        .after_help("Run `cargo help run` for more detailed information.\n")
+        .after_help(color_print::cstr!(
+            "Run `<blue,bold>cargo help run</>` for more detailed information.\n"
+        ))
 }
 
 pub fn exec(config: &mut Config, args: &ArgMatches) -> CliResult {