Return std::process::ExitCode instead of exiting with std::process::exit

rust-lang/rust#77553 still exists on nightly-2025-01-30.

Author: taiki-e

src/cli.rs

@@ -30,7 +30,7 @@ pub(crate) struct Args {
 }
 
 impl Args {
-    pub(crate) fn parse() -> Result<Self> {
+    pub(crate) fn parse() -> Result<Option<Self>> {
         const SUBCMD: &str = "no-dev-deps";
 
         // rustc/cargo args must be valid Unicode
@@ -99,11 +99,11 @@ impl Args {
 
                 Short('h') | Long("help") if subcommand.is_none() => {
                     print!("{USAGE}");
-                    std::process::exit(0);
+                    return Ok(None);
                 }
                 Short('V') | Long("version") if subcommand.is_none() => {
                     println!("{} {}", env!("CARGO_PKG_NAME"), env!("CARGO_PKG_VERSION"));
-                    std::process::exit(0);
+                    return Ok(None);
                 }
 
                 // passthrough
@@ -152,7 +152,7 @@ impl Args {
             cargo_args.push(path.clone());
         }
 
-        Ok(Self { no_private, manifest_path, cargo_args, rest })
+        Ok(Some(Self { no_private, manifest_path, cargo_args, rest }))
     }
 }
 

src/main.rs

@@ -15,24 +15,26 @@ mod manifest;
 mod metadata;
 mod restore;
 
-use std::env;
+use std::{env, process::ExitCode};
 
 use anyhow::Result;
 
 use crate::{cargo::Workspace, cli::Args};
 
-fn main() {
+fn main() -> ExitCode {
     term::init_coloring();
     if let Err(e) = try_main() {
         error!("{e:#}");
     }
     if term::error() || term::warn() && env::var_os("CARGO_NO_DEV_DEPS_DENY_WARNINGS").is_some() {
-        std::process::exit(1)
+        ExitCode::FAILURE
+    } else {
+        ExitCode::SUCCESS
     }
 }
 
 fn try_main() -> Result<()> {
-    let args = Args::parse()?;
+    let Some(args) = Args::parse()? else { return Ok(()) };
     let ws = Workspace::new(args.manifest_path.as_deref())?;
 
     let no_dev_deps = true;