fix(cli): Control clap colors through term.color

Fixes rust-lang#9012

src/bin/cargo/cli.rs

@@ -1,5 +1,6 @@
 use anyhow::{anyhow, Context as _};
 use cargo::core::{features, CliUnstable};
+use cargo::util::config::TermConfig;
 use cargo::{drop_print, drop_println, CargoResult};
 use clap::builder::UnknownArgumentValueParser;
 use itertools::Itertools;
@@ -12,14 +13,15 @@ use super::commands;
 use super::list_commands;
 use crate::command_prelude::*;
 use crate::util::is_rustup;
+use cargo::core::shell::ColorChoice;
 use cargo::util::style;
 
 pub fn main(gctx: &mut GlobalContext) -> CliResult {
     // CAUTION: Be careful with using `config` until it is configured below.
     // In general, try to avoid loading config values unless necessary (like
     // the [alias] table).
 
-    let args = cli().try_get_matches()?;
+    let args = cli(gctx).try_get_matches()?;
 
     // Update the process-level notion of cwd
     if let Some(new_cwd) = args.get_one::<std::path::PathBuf>("directory") {
@@ -172,7 +174,7 @@ Run with `{literal}cargo -Z{literal:#} {placeholder}[FLAG] [COMMAND]{placeholder
         Some((cmd, args)) => (cmd, args),
         _ => {
             // No subcommand provided.
-            cli().print_help()?;
+            cli(gctx).print_help()?;
             return Ok(());
         }
     };
@@ -335,7 +337,7 @@ For more information, see issue #12207 <https://github.com/rust-lang/cargo/issue
                 // Note that an alias to an external command will not receive
                 // these arguments. That may be confusing, but such is life.
                 let global_args = GlobalArgs::new(sub_args);
-                let new_args = cli().no_binary_name(true).try_get_matches_from(alias)?;
+                let new_args = cli(gctx).no_binary_name(true).try_get_matches_from(alias)?;
 
                 let new_cmd = new_args.subcommand_name().expect("subcommand is required");
                 already_expanded.push(cmd.to_string());
@@ -511,7 +513,19 @@ impl GlobalArgs {
     }
 }
 
-pub fn cli() -> Command {
+pub fn cli(gctx: &GlobalContext) -> Command {
+    // Don't let config errors get in the way of parsing arguments
+    let term = gctx.get::<TermConfig>("term").unwrap_or_default();
+    let color = term
+        .color
+        .and_then(|c| c.parse().ok())
+        .unwrap_or(ColorChoice::CargoAuto);
+    let color = match color {
+        ColorChoice::Always => clap::ColorChoice::Always,
+        ColorChoice::Never => clap::ColorChoice::Never,
+        ColorChoice::CargoAuto => clap::ColorChoice::Auto,
+    };
+
     let usage = if is_rustup() {
         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 {
@@ -536,6 +550,7 @@ pub fn cli() -> Command {
         // We also want these to come before auto-generated `--help`
         .next_display_order(800)
         .allow_external_subcommands(true)
+        .color(color)
         .styles(styles)
         // Provide a custom help subcommand for calling into man pages
         .disable_help_subcommand(true)
@@ -645,7 +660,8 @@ See '<cyan,bold>cargo help</> <cyan><<command>></>' for more information on a sp
 
 #[test]
 fn verify_cli() {
-    cli().debug_assert();
+    let gctx = GlobalContext::default().unwrap();
+    cli(&gctx).debug_assert();
 }
 
 #[test]

src/bin/cargo/commands/help.rs

@@ -39,7 +39,7 @@ pub fn exec(gctx: &mut GlobalContext, args: &ArgMatches) -> CliResult {
             }
         }
     } else {
-        let mut cmd = crate::cli::cli();
+        let mut cmd = crate::cli::cli(gctx);
         let _ = cmd.print_help();
     }
     Ok(())

src/cargo/util/config/mod.rs

@@ -2636,14 +2636,14 @@ impl BuildTargetConfig {
 }
 
 #[derive(Deserialize, Default)]
-struct TermConfig {
-    verbose: Option<bool>,
-    quiet: Option<bool>,
-    color: Option<String>,
-    hyperlinks: Option<bool>,
+pub struct TermConfig {
+    pub verbose: Option<bool>,
+    pub quiet: Option<bool>,
+    pub color: Option<String>,
+    pub hyperlinks: Option<bool>,
     #[serde(default)]
     #[serde(deserialize_with = "progress_or_string")]
-    progress: Option<ProgressConfig>,
+    pub progress: Option<ProgressConfig>,
 }
 
 #[derive(Debug, Default, Deserialize)]