Replace remaining early exits with proper ErrorMessage returns

Author: phil-opp

src/help/mod.rs

@@ -1,4 +1,4 @@
-use std::process;
+use crate::ErrorMessage;
 
 const HELP: &str = include_str!("help.txt");
 const BUILD_HELP: &str = include_str!("build_help.txt");
@@ -31,9 +31,7 @@ pub(crate) fn test_help() {
     print!("{}", TEST_HELP);
 }
 
-pub(crate) fn no_subcommand() -> ! {
-    println!("Please invoke `bootimage` with a subcommand (e.g. `bootimage build`).");
-    println!();
-    println!("See `bootimage --help` for more information.");
-    process::exit(1);
+pub(crate) fn no_subcommand() -> ErrorMessage {
+    "Please invoke `bootimage` with a subcommand (e.g. `bootimage build`).\n\n\
+    See `bootimage --help` for more information.".into()
 }

src/lib.rs

@@ -64,14 +64,14 @@ pub fn run() -> Result<Option<i32>, ErrorMessage> {
         Command::Run(args) => subcommand::run::run(args).map(Some),
         Command::Test(args) => subcommand::test::test(args).map(none),
         Command::Runner(args) => subcommand::runner::runner(args).map(Some),
-        Command::NoSubcommand => help::no_subcommand(),
         Command::Help => Ok(help::help()).map(none),
         Command::BuildHelp => Ok(help::build_help()).map(none),
         Command::CargoBootimageHelp => Ok(help::cargo_bootimage_help()).map(none),
         Command::RunHelp => Ok(help::run_help()).map(none),
         Command::RunnerHelp => Ok(help::runner_help()).map(none),
         Command::TestHelp => Ok(help::test_help()).map(none),
         Command::Version => Ok(println!("bootimage {}", env!("CARGO_PKG_VERSION"))).map(none),
+        Command::NoSubcommand => Err(help::no_subcommand()),
     }
 }
 

src/subcommand/build.rs

@@ -15,7 +15,7 @@ pub(crate) fn build_impl(
     args: &Args,
     quiet: bool,
 ) -> Result<Vec<PathBuf>, ErrorMessage> {
-    run_cargo_fetch(&args);
+    run_cargo_fetch(&args).map_err(|()| "cargo fetch failed")?;
 
     let executables = builder.build_kernel(&args.cargo_args, quiet)?;
     if executables.len() == 0 {
@@ -40,14 +40,16 @@ pub(crate) fn build_impl(
     Ok(bootimages)
 }
 
-fn run_cargo_fetch(args: &Args) {
+fn run_cargo_fetch(args: &Args) -> Result<(), ()> {
     let mut command = process::Command::new("cargo");
     command.arg("fetch");
     if let Some(manifest_path) = args.manifest_path() {
         command.arg("--manifest-path");
         command.arg(manifest_path);
     }
-    if !command.status().map(|s| s.success()).unwrap_or(false) {
-        process::exit(1);
+    if command.status().map(|s| s.success()).unwrap_or(false) {
+        Ok(())
+    } else {
+        Err(())
     }
 }

src/subcommand/test.rs

@@ -94,7 +94,7 @@ pub(crate) fn test(mut args: Args) -> Result<(), ErrorMessage> {
         for test in tests.iter().filter(|t| t.1 != TestResult::Ok) {
             writeln!(io::stderr(), "    {}: {:?}", test.0, test.1)?;
         }
-        process::exit(1);
+        Err("Some tests failed".into())
     }
 }