Auto merge of #12578 - epage:help, r=weihanglo

feat(help): Add styling to help output

### What does this PR try to resolve?

Try to make `--help` output easier to parse by using terminal styling

Screenshots:

![Screenshot from 2023-09-06 09-57-11](https://github.com/rust-lang/cargo/assets/60961/61069af4-ef05-40ad-9240-fedea44d4c71)

![Screenshot from 2023-09-06 09-57-21](https://github.com/rust-lang/cargo/assets/60961/d2e69024-42aa-47c0-ad0f-24e43551b8db)

![Screenshot from 2023-09-06 09-57-36](https://github.com/rust-lang/cargo/assets/60961/e3d895e2-745f-48c6-9e84-d6fb67198d6d)

*(`nargo` is my shell script wrapping `cargo run --manifest-path cargo/Cargo.toml`)*

### How should we test and review this PR?

At this time, the only styling snapshotting library I know of is a pain to use, so testing this requires manually running the commands which I did.  Screenshots are included for easier evaluation of the general idea.

Snapshotting of the plain text output ensures we don't have accidental formatting regressions from this change since the formatting isn't as obvious from looking at the code.

### Additional information

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, unblocking this.  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.

I used the `color-print` crate to allow something almost html-like for styling `&static str`.  Alternatively, we could directly embed the ANSI escape codes harder to get write, harder to inspect), or we could do the styling at runtime and enable the `string` feature in clap.

I decided to *not* style `Arg::help` messages because
- It might be distracting to have the descriptions lit up like a
  christmas tree
- It is a lot more work

The one exception I made was for `--list` since it is for a
psuedo-command (`...`) and I wanted to intentionally draw attention to
it.

#12593 made styling of `cargo -h` cleaner imo.
#12592 and #12594 were improvements I noticed while doing this.

Author: bors

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 = "0.17.0"
 clap = "4.4.2"
+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"] }
@@ -129,6 +130,7 @@ 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

@@ -513,53 +513,64 @@ impl GlobalArgs {
 
 pub fn cli() -> Command {
     let usage = if is_rustup() {
-        "cargo [+toolchain] [OPTIONS] [COMMAND]\n       cargo [+toolchain] [OPTIONS] -Zscript <MANIFEST_RS> [ARGS]..."
+        color_print::cstr!("<cyan,bold>cargo</> <cyan>[+toolchain] [OPTIONS] [COMMAND]</>\n       <cyan,bold>cargo</> <cyan>[+toolchain] [OPTIONS]</> <cyan,bold>-Zscript</> <cyan><<MANIFEST_RS>> [ARGS]...</>")
     } else {
-        "cargo [OPTIONS] [COMMAND]\n       cargo [OPTIONS] -Zscript <MANIFEST_RS> [ARGS]..."
+        color_print::cstr!("<cyan,bold>cargo</> <cyan>[OPTIONS] [COMMAND]</>\n       <cyan,bold>cargo</> <cyan>[OPTIONS]</> <cyan,bold>-Zscript</> <cyan><<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::Cyan.on_default() | Effects::BOLD)
+            .placeholder(AnsiColor::Cyan.on_default())
+            .error(AnsiColor::Red.on_default() | Effects::BOLD)
+            .valid(AnsiColor::Cyan.on_default() | Effects::BOLD)
+            .invalid(AnsiColor::Yellow.on_default() | Effects::BOLD)
+    };
+
     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:</> {usage}
 
-Options:
+<green,bold>Options:</>
 {options}
 
-Commands:
-    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 all commands with --list
-
-See 'cargo help <command>' for more information on a specific command.\n",
-        )
+<green,bold>Commands:</>
+    <cyan,bold>build</>, <cyan,bold>b</>    Compile the current package
+    <cyan,bold>check</>, <cyan,bold>c</>    Analyze the current package and report errors, but don't build object files
+    <cyan,bold>clean</>       Remove the target directory
+    <cyan,bold>doc</>, <cyan,bold>d</>      Build this package's and its dependencies' documentation
+    <cyan,bold>new</>         Create a new cargo package
+    <cyan,bold>init</>        Create a new cargo package in an existing directory
+    <cyan,bold>add</>         Add dependencies to a manifest file
+    <cyan,bold>remove</>      Remove dependencies from a manifest file
+    <cyan,bold>run</>, <cyan,bold>r</>      Run a binary or example of the local package
+    <cyan,bold>test</>, <cyan,bold>t</>     Run the tests
+    <cyan,bold>bench</>       Run the benchmarks
+    <cyan,bold>update</>      Update dependencies listed in Cargo.lock
+    <cyan,bold>search</>      Search registry for crates
+    <cyan,bold>publish</>     Package and upload this package to the registry
+    <cyan,bold>install</>     Install a Rust binary. Default location is $HOME/.cargo/bin
+    <cyan,bold>uninstall</>   Uninstall a Rust binary
+    <cyan>...</>         See all commands with <cyan,bold>--list</>
+
+See '<cyan,bold>cargo help</> <cyan><<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(

src/bin/cargo/cli.rs

@@ -18,12 +18,12 @@ pub fn cli() -> Command {
     clap::Command::new("add")
         .about("Add dependencies to a Cargo.toml manifest file")
         .override_usage(
-            "\
-       cargo add [OPTIONS] <DEP>[@<VERSION>] ...
-       cargo add [OPTIONS] --path <PATH> ...
-       cargo add [OPTIONS] --git <URL> ..."
-        )
-        .after_help("Run `cargo help add` for more detailed information.\n")
+            color_print::cstr!("\
+       <cyan,bold>cargo add</> <cyan>[OPTIONS] <<DEP>>[@<<VERSION>>] ...</>
+       <cyan,bold>cargo add</> <cyan>[OPTIONS]</> <cyan,bold>--path</> <cyan><<PATH>> ...</>
+       <cyan,bold>cargo add</> <cyan>[OPTIONS]</> <cyan,bold>--git</> <cyan><<URL>> ...</>"
+        ))
+        .after_help(color_print::cstr!("Run `<cyan,bold>cargo help add</>` for more detailed information.\n"))
         .group(clap::ArgGroup::new("selected").multiple(true).required(true))
         .args([
             clap::Arg::new("crates")

src/bin/cargo/commands/add.rs

@@ -50,7 +50,9 @@ pub fn cli() -> Command {
         .arg_unit_graph()
         .arg_timings()
         .arg_manifest_path()
-        .after_help("Run `cargo help bench` for more detailed information.\n")
+        .after_help(color_print::cstr!(
+            "Run `<cyan,bold>cargo help bench</>` for more detailed information.\n"
+        ))
 }
 
 pub fn exec(config: &mut Config, args: &ArgMatches) -> CliResult {

src/bin/cargo/commands/bench.rs

@@ -46,7 +46,9 @@ pub fn cli() -> Command {
         .arg_unit_graph()
         .arg_timings()
         .arg_manifest_path()
-        .after_help("Run `cargo help build` for more detailed information.\n")
+        .after_help(color_print::cstr!(
+            "Run `<cyan,bold>cargo help build</>` for more detailed information.\n"
+        ))
 }
 
 pub fn exec(config: &mut Config, args: &ArgMatches) -> CliResult {

src/bin/cargo/commands/build.rs

@@ -37,7 +37,9 @@ pub fn cli() -> Command {
         .arg_unit_graph()
         .arg_timings()
         .arg_manifest_path()
-        .after_help("Run `cargo help check` for more detailed information.\n")
+        .after_help(color_print::cstr!(
+            "Run `<cyan,bold>cargo help check</>` for more detailed information.\n"
+        ))
 }
 
 pub fn exec(config: &mut Config, args: &ArgMatches) -> CliResult {

src/bin/cargo/commands/check.rs

@@ -14,7 +14,9 @@ pub fn cli() -> Command {
         .arg_target_triple("Target triple to clean output for")
         .arg_target_dir()
         .arg_manifest_path()
-        .after_help("Run `cargo help clean` for more detailed information.\n")
+        .after_help(color_print::cstr!(
+            "Run `<cyan,bold>cargo help clean</>` for more detailed information.\n"
+        ))
 }
 
 pub fn exec(config: &mut Config, args: &ArgMatches) -> CliResult {

src/bin/cargo/commands/clean.rs

@@ -40,7 +40,9 @@ pub fn cli() -> Command {
         .arg_unit_graph()
         .arg_timings()
         .arg_manifest_path()
-        .after_help("Run `cargo help doc` for more detailed information.\n")
+        .after_help(color_print::cstr!(
+            "Run `<cyan,bold>cargo help doc</>` for more detailed information.\n"
+        ))
 }
 
 pub fn exec(config: &mut Config, args: &ArgMatches) -> CliResult {

src/bin/cargo/commands/doc.rs

@@ -9,7 +9,9 @@ pub fn cli() -> Command {
         .arg_quiet()
         .arg_target_triple("Fetch dependencies for the target triple")
         .arg_manifest_path()
-        .after_help("Run `cargo help fetch` for more detailed information.\n")
+        .after_help(color_print::cstr!(
+            "Run `<cyan,bold>cargo help fetch</>` for more detailed information.\n"
+        ))
 }
 
 pub fn exec(config: &mut Config, args: &ArgMatches) -> CliResult {