Print warning if there is no toolchain to update

Cargo.toml

@@ -18,6 +18,7 @@ name = "fuelup"
 path = "src/main.rs"
 
 [dependencies]
+ansi_term = "0.12.1"
 ansiterm = "0.12.2"
 anyhow = "1"
 clap = { version = "4.2.4", features = ["cargo", "derive", "env"] }

src/fmt.rs

@@ -1,7 +1,15 @@
+use crate::target_triple::TargetTriple;
+use ansi_term::Colour;
 use ansiterm::Style;
 use tracing::info;
 
-use crate::target_triple::TargetTriple;
+pub fn println_error<X: Into<String>>(txt: X) {
+    tracing::warn!("{}: {}", Colour::Red.paint("error"), txt.into());
+}
+
+pub fn println_warn<X: Into<String>>(txt: X) {
+    tracing::warn!("{}: {}", Colour::Yellow.paint("warning"), txt.into());
+}
 
 pub fn bold(text: &str) -> String {
     let style = Style::new().bold();

src/ops/fuelup_update.rs

@@ -1,7 +1,7 @@
 use crate::{
     channel::Channel,
     config::Config,
-    fmt::{bold, colored_bold},
+    fmt::{bold, colored_bold, println_error},
     path::warn_existing_fuel_executables,
     toolchain::{DistToolchainDescription, Toolchain},
 };
@@ -20,6 +20,13 @@ pub fn update() -> Result<()> {
 
     warn_existing_fuel_executables()?;
 
+    if toolchains.is_empty() {
+        println_error(
+            "No toolchains are installed. Use `fuelup default <toolchain>` to install a toolchain.",
+        );
+        return Ok(());
+    }
+
     for toolchain in toolchains {
         let mut installed_bins = String::new();
         let mut errored_bins = String::new();

src/path.rs

@@ -1,15 +1,12 @@
+use crate::{constants::FUEL_TOOLCHAIN_TOML_FILE, fmt::println_warn};
 use anyhow::{bail, Result};
 use component::Components;
+use dirs;
 use std::env;
 use std::{
     fs,
     path::{Path, PathBuf},
 };
-use tracing::warn;
-
-use dirs;
-
-use crate::constants::FUEL_TOOLCHAIN_TOML_FILE;
 
 pub const FUELUP_DIR: &str = ".fuelup";
 pub const FUELUP_HOME: &str = "FUELUP_HOME";
@@ -76,8 +73,6 @@ pub fn warn_existing_fuel_executables() -> Result<()> {
         vec![]
     }
 
-    let mut summary = String::new();
-
     for c in components {
         for e in c.executables {
             if let Some(path) = search_directories()
@@ -119,15 +114,12 @@ pub fn warn_existing_fuel_executables() -> Result<()> {
                 }
 
                 if !message.is_empty() {
-                    summary.push_str(&message);
-                    summary.push('\n');
+                    println_warn(message);
                 }
             }
         }
     }
 
-    warn!("{}", summary);
-
     Ok(())
 }