Auto merge of #13463 - epage:term_color, r=weihanglo

fix(cli): Control clap colors through config

### What does this PR try to resolve?

Part of #9012

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

To accomplish this, I pivoted in how we handle `-C`.  In #11029, I made the config lazily loaded.  Instead, we are now reloading the config for `-C` like we do for "cargo script" and `cargo install`.  If there is any regression, it will be felt by those commands as well and we can fix all together.  As this is unstable, if there is a regression, the impact is less.  This allowed us access to the full config for getting the color setting, rather than taking more limited approaches like checking only `CARGO_TERM_CONFIG`.

### Additional information

src/bin/cargo/cli.rs

@@ -1,6 +1,6 @@
 use anyhow::{anyhow, Context as _};
-use cargo::core::shell::Shell;
 use cargo::core::{features, CliUnstable};
+use cargo::util::config::TermConfig;
 use cargo::{drop_print, drop_println, CargoResult};
 use clap::builder::UnknownArgumentValueParser;
 use itertools::Itertools;
@@ -13,14 +13,17 @@ 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(lazy_gctx: &mut LazyContext) -> CliResult {
-    let args = cli().try_get_matches()?;
+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(gctx).try_get_matches()?;
 
     // Update the process-level notion of cwd
-    // This must be completed before config is initialized
-    assert_eq!(lazy_gctx.is_init(), false);
     if let Some(new_cwd) = args.get_one::<std::path::PathBuf>("directory") {
         // This is a temporary hack. This cannot access `Config`, so this is a bit messy.
         // This does not properly parse `-Z` flags that appear after the subcommand.
@@ -40,13 +43,9 @@ pub fn main(lazy_gctx: &mut LazyContext) -> CliResult {
             .into());
         }
         std::env::set_current_dir(&new_cwd).context("could not change to requested directory")?;
+        gctx.reload_cwd()?;
     }
 
-    // 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 gctx = lazy_gctx.get_mut();
-
     let (expanded_args, global_args) = expand_aliases(gctx, args, vec![])?;
 
     if expanded_args
@@ -175,7 +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(());
         }
     };
@@ -338,7 +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());
@@ -514,7 +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 {
@@ -539,6 +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)
@@ -646,53 +658,10 @@ See '<cyan,bold>cargo help</> <cyan><<command>></>' for more information on a sp
         .subcommands(commands::builtin())
 }
 
-/// Delay loading [`GlobalContext`] until access.
-///
-/// In the common path, the [`GlobalContext`] is dependent on CLI parsing and shouldn't be loaded until
-/// after that is done but some other paths (like fix or earlier errors) might need access to it,
-/// so this provides a way to share the instance and the implementation across these different
-/// accesses.
-pub struct LazyContext {
-    gctx: Option<GlobalContext>,
-}
-
-impl LazyContext {
-    pub fn new() -> Self {
-        Self { gctx: None }
-    }
-
-    /// Check whether the config is loaded
-    ///
-    /// This is useful for asserts in case the environment needs to be setup before loading
-    pub fn is_init(&self) -> bool {
-        self.gctx.is_some()
-    }
-
-    /// Get the config, loading it if needed
-    ///
-    /// On error, the process is terminated
-    pub fn get(&mut self) -> &GlobalContext {
-        self.get_mut()
-    }
-
-    /// Get the config, loading it if needed
-    ///
-    /// On error, the process is terminated
-    pub fn get_mut(&mut self) -> &mut GlobalContext {
-        self.gctx
-            .get_or_insert_with(|| match GlobalContext::default() {
-                Ok(cfg) => cfg,
-                Err(e) => {
-                    let mut shell = Shell::new();
-                    cargo::exit_with_error(e.into(), &mut shell)
-                }
-            })
-    }
-}
-
 #[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/bin/cargo/main.rs

@@ -1,5 +1,6 @@
 #![allow(clippy::self_named_module_files)] // false positive in `commands/build.rs`
 
+use cargo::core::shell::Shell;
 use cargo::util::network::http::http_handle;
 use cargo::util::network::http::needs_custom_http_transport;
 use cargo::util::{self, closest_msg, command_prelude, CargoResult};
@@ -19,17 +20,23 @@ use crate::command_prelude::*;
 fn main() {
     setup_logger();
 
-    let mut lazy_gctx = cli::LazyContext::new();
+    let mut gctx = match GlobalContext::default() {
+        Ok(gctx) => gctx,
+        Err(e) => {
+            let mut shell = Shell::new();
+            cargo::exit_with_error(e.into(), &mut shell)
+        }
+    };
 
     let result = if let Some(lock_addr) = cargo::ops::fix_get_proxy_lock_addr() {
-        cargo::ops::fix_exec_rustc(lazy_gctx.get(), &lock_addr).map_err(|e| CliError::from(e))
+        cargo::ops::fix_exec_rustc(&gctx, &lock_addr).map_err(|e| CliError::from(e))
     } else {
         let _token = cargo::util::job::setup();
-        cli::main(&mut lazy_gctx)
+        cli::main(&mut gctx)
     };
 
     match result {
-        Err(e) => cargo::exit_with_error(e, &mut lazy_gctx.get_mut().shell()),
+        Err(e) => cargo::exit_with_error(e, &mut *gctx.shell()),
         Ok(()) => {}
     }
 }

src/cargo/core/shell.rs

@@ -9,44 +9,6 @@ use crate::util::errors::CargoResult;
 use crate::util::hostname;
 use crate::util::style::*;
 
-pub enum TtyWidth {
-    NoTty,
-    Known(usize),
-    Guess(usize),
-}
-
-impl TtyWidth {
-    /// Returns the width of the terminal to use for diagnostics (which is
-    /// relayed to rustc via `--diagnostic-width`).
-    pub fn diagnostic_terminal_width(&self) -> Option<usize> {
-        // ALLOWED: For testing cargo itself only.
-        #[allow(clippy::disallowed_methods)]
-        if let Ok(width) = std::env::var("__CARGO_TEST_TTY_WIDTH_DO_NOT_USE_THIS") {
-            return Some(width.parse().unwrap());
-        }
-        match *self {
-            TtyWidth::NoTty | TtyWidth::Guess(_) => None,
-            TtyWidth::Known(width) => Some(width),
-        }
-    }
-
-    /// Returns the width used by progress bars for the tty.
-    pub fn progress_max_width(&self) -> Option<usize> {
-        match *self {
-            TtyWidth::NoTty => None,
-            TtyWidth::Known(width) | TtyWidth::Guess(width) => Some(width),
-        }
-    }
-}
-
-/// The requested verbosity of output.
-#[derive(Debug, Clone, Copy, PartialEq)]
-pub enum Verbosity {
-    Verbose,
-    Normal,
-    Quiet,
-}
-
 /// An abstraction around console output that remembers preferences for output
 /// verbosity and color.
 pub struct Shell {
@@ -77,31 +39,6 @@ impl fmt::Debug for Shell {
     }
 }
 
-/// A `Write`able object, either with or without color support
-enum ShellOut {
-    /// A plain write object without color support
-    Write(AutoStream<Box<dyn Write>>),
-    /// Color-enabled stdio, with information on whether color should be used
-    Stream {
-        stdout: AutoStream<std::io::Stdout>,
-        stderr: AutoStream<std::io::Stderr>,
-        stderr_tty: bool,
-        color_choice: ColorChoice,
-        hyperlinks: bool,
-    },
-}
-
-/// Whether messages should use color output
-#[derive(Debug, PartialEq, Clone, Copy)]
-pub enum ColorChoice {
-    /// Force color output
-    Always,
-    /// Force disable color output
-    Never,
-    /// Intelligently guess whether to use color output
-    CargoAuto,
-}
-
 impl Shell {
     /// Creates a new shell (color choice and verbosity), defaulting to 'auto' color and verbose
     /// output.
@@ -299,18 +236,10 @@ impl Shell {
             ..
         } = self.output
         {
-            let cfg = match color {
-                Some("always") => ColorChoice::Always,
-                Some("never") => ColorChoice::Never,
-
-                Some("auto") | None => ColorChoice::CargoAuto,
-
-                Some(arg) => anyhow::bail!(
-                    "argument for --color must be auto, always, or \
-                     never, but found `{}`",
-                    arg
-                ),
-            };
+            let cfg = color
+                .map(|c| c.parse())
+                .transpose()?
+                .unwrap_or(ColorChoice::CargoAuto);
             *color_choice = cfg;
             let stdout_choice = cfg.to_anstream_color_choice();
             let stderr_choice = cfg.to_anstream_color_choice();
@@ -444,6 +373,20 @@ impl Default for Shell {
     }
 }
 
+/// A `Write`able object, either with or without color support
+enum ShellOut {
+    /// A plain write object without color support
+    Write(AutoStream<Box<dyn Write>>),
+    /// Color-enabled stdio, with information on whether color should be used
+    Stream {
+        stdout: AutoStream<std::io::Stdout>,
+        stderr: AutoStream<std::io::Stderr>,
+        stderr_tty: bool,
+        color_choice: ColorChoice,
+        hyperlinks: bool,
+    },
+}
+
 impl ShellOut {
     /// Prints out a message with a status. The status comes first, and is bold plus the given
     /// color. The status can be justified, in which case the max width that will right align is
@@ -488,6 +431,55 @@ impl ShellOut {
     }
 }
 
+pub enum TtyWidth {
+    NoTty,
+    Known(usize),
+    Guess(usize),
+}
+
+impl TtyWidth {
+    /// Returns the width of the terminal to use for diagnostics (which is
+    /// relayed to rustc via `--diagnostic-width`).
+    pub fn diagnostic_terminal_width(&self) -> Option<usize> {
+        // ALLOWED: For testing cargo itself only.
+        #[allow(clippy::disallowed_methods)]
+        if let Ok(width) = std::env::var("__CARGO_TEST_TTY_WIDTH_DO_NOT_USE_THIS") {
+            return Some(width.parse().unwrap());
+        }
+        match *self {
+            TtyWidth::NoTty | TtyWidth::Guess(_) => None,
+            TtyWidth::Known(width) => Some(width),
+        }
+    }
+
+    /// Returns the width used by progress bars for the tty.
+    pub fn progress_max_width(&self) -> Option<usize> {
+        match *self {
+            TtyWidth::NoTty => None,
+            TtyWidth::Known(width) | TtyWidth::Guess(width) => Some(width),
+        }
+    }
+}
+
+/// The requested verbosity of output.
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub enum Verbosity {
+    Verbose,
+    Normal,
+    Quiet,
+}
+
+/// Whether messages should use color output
+#[derive(Debug, PartialEq, Clone, Copy)]
+pub enum ColorChoice {
+    /// Force color output
+    Always,
+    /// Force disable color output
+    Never,
+    /// Intelligently guess whether to use color output
+    CargoAuto,
+}
+
 impl ColorChoice {
     /// Converts our color choice to anstream's version.
     fn to_anstream_color_choice(self) -> anstream::ColorChoice {
@@ -499,6 +491,25 @@ impl ColorChoice {
     }
 }
 
+impl std::str::FromStr for ColorChoice {
+    type Err = anyhow::Error;
+    fn from_str(color: &str) -> Result<Self, Self::Err> {
+        let cfg = match color {
+            "always" => ColorChoice::Always,
+            "never" => ColorChoice::Never,
+
+            "auto" => ColorChoice::CargoAuto,
+
+            arg => anyhow::bail!(
+                "argument for --color must be auto, always, or \
+                     never, but found `{}`",
+                arg
+            ),
+        };
+        Ok(cfg)
+    }
+}
+
 fn supports_color(choice: anstream::ColorChoice) -> bool {
     match choice {
         anstream::ColorChoice::Always