Add some color to error messages (#1028)

* Add some color to error messages

This commit updates the errors printed by the CLI to have `error` in
red, the main error message in bold, and the rest of it is unchanged.

* Fix tests

* Fix no-default-features build

crates/wasm-compose/tests/compositions/component-missing/error.txt

@@ -1,5 +1,5 @@
 failed to parse component `tests/compositions/component-missing/a.wat`
 
 Caused by:
-    0: failed to read from `tests/compositions/component-missing/a.wat`: No such file or directory (os error 2)
+    0: failed to read from `tests/compositions/component-missing/a.wat`
     1: No such file or directory (os error 2)

crates/wasm-compose/tests/compositions/missing-explicit-dep/error.txt

@@ -1,5 +1,5 @@
 failed to parse component `tests/compositions/missing-explicit-dep/a.wat`
 
 Caused by:
-    0: failed to read from `tests/compositions/missing-explicit-dep/a.wat`: No such file or directory (os error 2)
+    0: failed to read from `tests/compositions/missing-explicit-dep/a.wat`
     1: No such file or directory (os error 2)

crates/wasm-compose/tests/compositions/missing-root/error.txt

@@ -1,5 +1,5 @@
 failed to parse component `tests/compositions/missing-root/root.wat`
 
 Caused by:
-    0: failed to read from `tests/compositions/missing-root/root.wat`: No such file or directory (os error 2)
+    0: failed to read from `tests/compositions/missing-root/root.wat`
     1: No such file or directory (os error 2)

crates/wat/src/lib.rs

@@ -287,7 +287,7 @@ impl fmt::Display for Error {
             },
             ErrorKind::Io { err, file, .. } => match file {
                 Some(file) => {
-                    write!(f, "failed to read from `{}`: {}", file.display(), err)
+                    write!(f, "failed to read from `{}`", file.display())
                 }
                 None => err.fmt(f),
             },
@@ -321,7 +321,7 @@ mod test {
         let e = parse_file("_does_not_exist_").unwrap_err();
         assert!(e
             .to_string()
-            .starts_with("failed to read from `_does_not_exist_`: "));
+            .starts_with("failed to read from `_does_not_exist_`"));
 
         let mut e = parse_bytes("()".as_bytes()).unwrap_err();
         e.set_path("foo");

src/bin/wasm-tools/addr2line.rs

@@ -41,6 +41,10 @@ pub struct Opts {
 }
 
 impl Opts {
+    pub fn general_opts(&self) -> &wasm_tools::GeneralOpts {
+        self.io.general_opts()
+    }
+
     pub fn run(&self) -> Result<()> {
         let wasm = self.io.parse_input_wasm()?;
 

src/bin/wasm-tools/component.rs

@@ -26,6 +26,14 @@ impl Opts {
             Opts::Embed(embed) => embed.run(),
         }
     }
+
+    pub fn general_opts(&self) -> &wasm_tools::GeneralOpts {
+        match self {
+            Opts::New(new) => new.general_opts(),
+            Opts::Wit(wit) => wit.general_opts(),
+            Opts::Embed(embed) => embed.general_opts(),
+        }
+    }
 }
 
 fn parse_optionally_name_file(s: &str) -> (&str, &str) {
@@ -91,6 +99,10 @@ pub struct NewOpts {
 }
 
 impl NewOpts {
+    fn general_opts(&self) -> &wasm_tools::GeneralOpts {
+        self.io.general_opts()
+    }
+
     /// Executes the application.
     fn run(self) -> Result<()> {
         let wasm = self.io.parse_input_wasm()?;
@@ -172,10 +184,13 @@ pub struct EmbedOpts {
 }
 
 impl EmbedOpts {
+    fn general_opts(&self) -> &wasm_tools::GeneralOpts {
+        self.io.general_opts()
+    }
+
     /// Executes the application.
     fn run(self) -> Result<()> {
         let wasm = if self.dummy {
-            self.io.init_logger();
             None
         } else {
             Some(self.io.parse_input_wasm()?)
@@ -217,7 +232,7 @@ impl EmbedOpts {
 #[derive(Parser)]
 pub struct WitOpts {
     #[clap(flatten)]
-    verbosity: wasm_tools::Verbosity,
+    general: wasm_tools::GeneralOpts,
 
     /// Input file or directory to process.
     ///
@@ -275,6 +290,10 @@ pub struct WitOpts {
 }
 
 impl WitOpts {
+    fn general_opts(&self) -> &wasm_tools::GeneralOpts {
+        &self.general
+    }
+
     /// Executes the application.
     fn run(self) -> Result<()> {
         let name = match &self.name {

src/bin/wasm-tools/compose.rs

@@ -7,12 +7,15 @@ pub struct Opts {
     #[clap(flatten)]
     cmd: WasmComposeCommand,
     #[clap(flatten)]
-    verbosity: wasm_tools::Verbosity,
+    general: wasm_tools::GeneralOpts,
 }
 
 impl Opts {
+    pub fn general_opts(&self) -> &wasm_tools::GeneralOpts {
+        &self.general
+    }
+
     pub fn run(self) -> Result<()> {
-        self.verbosity.init_logger();
         self.cmd.execute()
     }
 }

src/bin/wasm-tools/demangle.rs

@@ -19,6 +19,10 @@ pub struct Opts {
 }
 
 impl Opts {
+    pub fn general_opts(&self) -> &wasm_tools::GeneralOpts {
+        self.io.general_opts()
+    }
+
     pub fn run(&self) -> Result<()> {
         let input = self.io.parse_input_wasm()?;
         let mut module = wasm_encoder::Module::new();

src/bin/wasm-tools/dump.rs

@@ -15,6 +15,10 @@ pub struct Opts {
 }
 
 impl Opts {
+    pub fn general_opts(&self) -> &wasm_tools::GeneralOpts {
+        self.io.general_opts()
+    }
+
     pub fn run(&self) -> Result<()> {
         let input = self.io.parse_input_wasm()?;
         let output = self.io.output_writer()?;

src/bin/wasm-tools/main.rs

@@ -1,7 +1,8 @@
 use anyhow::Result;
 use clap::Parser;
-use std::io;
+use std::io::{self, Write};
 use std::process::ExitCode;
+use termcolor::{Color, ColorChoice, ColorSpec, StandardStream, WriteColor};
 
 macro_rules! subcommands {
     ($(
@@ -33,6 +34,15 @@ macro_rules! subcommands {
                     )*
                 }
             }
+
+            fn general_opts(&self) -> &wasm_tools::GeneralOpts {
+                match *self {
+                    $(
+                        #[cfg(feature = $string)]
+                        Self::$name(ref opts) => opts.general_opts(),
+                    )*
+                }
+            }
         }
     }
 }
@@ -58,7 +68,10 @@ subcommands! {
 }
 
 fn main() -> ExitCode {
-    let err = match <WasmTools as Parser>::parse().run() {
+    let args = <WasmTools as Parser>::parse();
+    args.general_opts().init_logger();
+    let color = args.general_opts().color;
+    let err = match args.run() {
         Ok(()) => return ExitCode::SUCCESS,
         Err(e) => e,
     };
@@ -72,10 +85,47 @@ fn main() -> ExitCode {
             _ => {}
         }
     }
-    eprintln!("Error: {:?}", err);
+
+    // ignore errors here since if we fail to print an error it's not like we
+    // can print it again.
+    let _ = print_error(color, err);
     ExitCode::FAILURE
 }
 
+fn print_error(color: ColorChoice, err: anyhow::Error) -> Result<()> {
+    let color = if color == ColorChoice::Auto && !atty::is(atty::Stream::Stderr) {
+        ColorChoice::Never
+    } else {
+        color
+    };
+    let mut stderr = StandardStream::stderr(color);
+    stderr.set_color(ColorSpec::new().set_fg(Some(Color::Red)).set_bold(true))?;
+    write!(stderr, "error")?;
+    stderr.set_color(ColorSpec::new().set_fg(None).set_bold(true))?;
+    write!(stderr, ": ")?;
+
+    let msg = err.to_string();
+    for (i, line) in msg.lines().enumerate() {
+        writeln!(stderr, "{line}")?;
+        if i == 0 {
+            stderr.set_color(ColorSpec::new().set_reset(true))?;
+        }
+    }
+
+    if err.chain().len() == 1 {
+        return Ok(());
+    }
+    writeln!(stderr, "\nCaused by:")?;
+    for (i, err) in err.chain().skip(1).enumerate() {
+        writeln!(
+            stderr,
+            "{i:>5}: {}",
+            err.to_string().replace("\n", "\n       ")
+        )?;
+    }
+    return Ok(());
+}
+
 /// If CARGO_VERSION_INFO is set, use it, otherwise use CARGO_PKG_VERSION.
 fn version() -> &'static str {
     option_env!("CARGO_VERSION_INFO").unwrap_or(env!("CARGO_PKG_VERSION"))

src/bin/wasm-tools/metadata.rs

@@ -15,6 +15,13 @@ impl Opts {
             Opts::Add(opts) => opts.run(),
         }
     }
+
+    pub fn general_opts(&self) -> &wasm_tools::GeneralOpts {
+        match self {
+            Opts::Show(opts) => opts.general_opts(),
+            Opts::Add(opts) => opts.general_opts(),
+        }
+    }
 }
 
 /// Read metadata (module name, producers) from a WebAssembly file.
@@ -29,6 +36,10 @@ pub struct ShowOpts {
 }
 
 impl ShowOpts {
+    pub fn general_opts(&self) -> &wasm_tools::GeneralOpts {
+        self.io.general_opts()
+    }
+
     pub fn run(&self) -> Result<()> {
         let input = self.io.parse_input_wasm()?;
         let mut output = self.io.output_writer()?;
@@ -58,6 +69,10 @@ pub struct AddOpts {
 }
 
 impl AddOpts {
+    pub fn general_opts(&self) -> &wasm_tools::GeneralOpts {
+        self.io.general_opts()
+    }
+
     pub fn run(&self) -> Result<()> {
         let input = self.io.parse_input_wasm()?;
 

src/bin/wasm-tools/mutate.rs

@@ -49,6 +49,10 @@ pub struct Opts {
 }
 
 impl Opts {
+    pub fn general_opts(&self) -> &wasm_tools::GeneralOpts {
+        self.io.general_opts()
+    }
+
     pub fn run(mut self) -> Result<()> {
         let input_wasm = self.io.parse_input_wasm()?;
 

src/bin/wasm-tools/objdump.rs

@@ -1,7 +1,7 @@
 use anyhow::Result;
-use termcolor::WriteColor;
 use std::io::Write;
 use std::ops::Range;
+use termcolor::WriteColor;
 use wasmparser::{Encoding, Parser, Payload::*};
 
 /// Dumps information about sections in a WebAssembly file.
@@ -15,6 +15,10 @@ pub struct Opts {
 }
 
 impl Opts {
+    pub fn general_opts(&self) -> &wasm_tools::GeneralOpts {
+        self.io.general_opts()
+    }
+
     pub fn run(&self) -> Result<()> {
         let input = self.io.parse_input_wasm()?;
 

src/bin/wasm-tools/parse.rs

@@ -16,6 +16,10 @@ pub struct Opts {
 }
 
 impl Opts {
+    pub fn general_opts(&self) -> &wasm_tools::GeneralOpts {
+        self.io.general_opts()
+    }
+
     pub fn run(&self) -> Result<()> {
         let binary = self.io.parse_input_wasm()?;
         self.io.output(wasm_tools::Output::Wasm {

src/bin/wasm-tools/print.rs

@@ -20,6 +20,10 @@ pub struct Opts {
 }
 
 impl Opts {
+    pub fn general_opts(&self) -> &wasm_tools::GeneralOpts {
+        self.io.general_opts()
+    }
+
     pub fn run(&self) -> Result<()> {
         let wasm = self.io.parse_input_wasm()?;
         let mut printer = wasmprinter::Printer::new();

src/bin/wasm-tools/shrink.rs

@@ -36,6 +36,10 @@ pub struct Opts {
 }
 
 impl Opts {
+    pub fn general_opts(&self) -> &wasm_tools::GeneralOpts {
+        self.io.general_opts()
+    }
+
     pub fn run(self) -> Result<()> {
         let input = self.io.parse_input_wasm()?;
         let initial_size = input.len();

src/bin/wasm-tools/smith.rs

@@ -76,7 +76,7 @@ pub struct Opts {
     module_config: Config,
 
     #[clap(flatten)]
-    verbosity: wasm_tools::Verbosity,
+    general: wasm_tools::GeneralOpts,
 }
 
 #[derive(Default, Debug, Parser, Clone, serde::Deserialize)]
@@ -195,8 +195,11 @@ struct Config {
 }
 
 impl Opts {
+    pub fn general_opts(&self) -> &wasm_tools::GeneralOpts {
+        &self.general
+    }
+
     pub fn run(&self) -> Result<()> {
-        self.verbosity.init_logger();
         let seed = match &self.input {
             Some(f) => {
                 std::fs::read(f).with_context(|| format!("failed to read '{}'", f.display()))?

src/bin/wasm-tools/strip.rs

@@ -27,6 +27,10 @@ pub struct Opts {
 }
 
 impl Opts {
+    pub fn general_opts(&self) -> &wasm_tools::GeneralOpts {
+        self.io.general_opts()
+    }
+
     pub fn run(&self) -> Result<()> {
         let input = self.io.parse_input_wasm()?;
         let to_delete = regex::RegexSet::new(self.delete.iter())?;

src/bin/wasm-tools/validate.rs

@@ -38,6 +38,10 @@ pub struct Opts {
 }
 
 impl Opts {
+    pub fn general_opts(&self) -> &wasm_tools::GeneralOpts {
+        self.io.general_opts()
+    }
+
     pub fn run(&self) -> Result<()> {
         // Note that here we're copying the contents of
         // `Validator::validate_all`, but the end is followed up with a parallel

src/bin/wasm-tools/wit_smith.rs

@@ -42,12 +42,15 @@ pub struct Opts {
     arbitrary_config: bool,
 
     #[clap(flatten)]
-    verbosity: wasm_tools::Verbosity,
+    general: wasm_tools::GeneralOpts,
 }
 
 impl Opts {
+    pub fn general_opts(&self) -> &wasm_tools::GeneralOpts {
+        &self.general
+    }
+
     pub fn run(&self) -> Result<()> {
-        self.verbosity.init_logger();
         let seed = match &self.input {
             Some(f) => {
                 std::fs::read(f).with_context(|| format!("failed to read '{}'", f.display()))?