fix(cli): handle terminals with limited color support

CHANGELOG.md

@@ -12,6 +12,10 @@ and its status can be checked out using `dfx canister migration-status`.
 The optimization functionality provided by `ic_wasm::optimize" cannot handle Wasm modules that contains 64-bit table.
 Instead of blocking the build, such optimization failure will issue a warning.
 
+### fix: prevent panic on terminals with limited color support
+
+Fixed a panic that could occur when running `dfx` on terminals lacking color support. The `term` crate has been replaced with raw ANSI escape codes, and colors are now only emitted when stderr is a TTY and the `NO_COLOR` environment variable is not set.
+
 ## Dependencies
 
 ### Motoko

src/dfx/Cargo.toml

@@ -107,7 +107,6 @@ supports-color = "2.1.0"
 sysinfo = "0.28.4"
 tar.workspace = true
 tempfile.workspace = true
-term = "0.7.0"
 thiserror.workspace = true
 time = { workspace = true, features = ["macros", "serde", "serde-human-readable"] }
 tokio = { workspace = true, features = ["full"] }

src/dfx/src/main.rs

@@ -15,6 +15,7 @@ use dfx_core::extension::manager::ExtensionManager;
 use indicatif::MultiProgress;
 use std::collections::HashMap;
 use std::ffi::OsString;
+use std::io::{IsTerminal, Write, stderr};
 use std::path::PathBuf;
 use std::time::Instant;
 use util::default_allowlisted_canisters;
@@ -72,8 +73,19 @@ fn setup_logging(opts: &CliOpts) -> (i64, slog::Logger, MultiProgress) {
     (verbose_level, logger, spinners)
 }
 
+/// Returns true if colored output should be used on stderr.
+/// Respects the NO_COLOR environment variable (https://no-color.org/).
+fn use_color() -> bool {
+    std::env::var_os("NO_COLOR").is_none() && stderr().is_terminal()
+}
+
 fn print_error_and_diagnosis(log_level: Option<i64>, err: Error, error_diagnosis: DiagnosedError) {
-    let mut stderr = util::stderr_wrapper::stderr_wrapper();
+    let mut stderr = stderr().lock();
+    let use_color = use_color();
+
+    const RED: &str = "\x1b[31m";
+    const YELLOW: &str = "\x1b[33m";
+    const RESET: &str = "\x1b[0m";
 
     // print error chain stack
     if log_level.unwrap_or_default() > 0 // DEBUG or more verbose
@@ -85,43 +97,35 @@ fn print_error_and_diagnosis(log_level: Option<i64>, err: Error, error_diagnosis
             }
 
             let (color, prefix) = if level == 0 {
-                (term::color::RED, "Error")
+                (RED, "Error")
             } else {
-                (term::color::YELLOW, "Caused by")
+                (YELLOW, "Caused by")
             };
-            stderr
-                .fg(color)
-                .expect("Failed to set stderr output color.");
-            write!(stderr, "{prefix}: ").expect("Failed to write to stderr.");
-            stderr
-                .reset()
-                .expect("Failed to reset stderr output color.");
+            if use_color {
+                write!(stderr, "{color}{prefix}: {RESET}").expect("Failed to write to stderr.");
+            } else {
+                write!(stderr, "{prefix}: ").expect("Failed to write to stderr.");
+            }
 
             writeln!(stderr, "{cause}").expect("Failed to write to stderr.");
         }
     }
 
     // print diagnosis
     if let Some(explanation) = error_diagnosis.explanation {
-        stderr
-            .fg(term::color::RED)
-            .expect("Failed to set stderr output color.");
-        write!(stderr, "Error: ").expect("Failed to write to stderr.");
-        stderr
-            .reset()
-            .expect("Failed to reset stderr output color.");
-
+        if use_color {
+            write!(stderr, "{RED}Error: {RESET}").expect("Failed to write to stderr.");
+        } else {
+            write!(stderr, "Error: ").expect("Failed to write to stderr.");
+        }
         writeln!(stderr, "{explanation}").expect("Failed to write to stderr.");
     }
     if let Some(action_suggestion) = error_diagnosis.action_suggestion {
-        stderr
-            .fg(term::color::YELLOW)
-            .expect("Failed to set stderr output color.");
-        write!(stderr, "To fix: ").expect("Failed to write to stderr.");
-        stderr
-            .reset()
-            .expect("Failed to reset stderr output color.");
-
+        if use_color {
+            write!(stderr, "{YELLOW}To fix: {RESET}").expect("Failed to write to stderr.");
+        } else {
+            write!(stderr, "To fix: ").expect("Failed to write to stderr.");
+        }
         writeln!(stderr, "{action_suggestion}").expect("Failed to write to stderr.");
     }
 }

src/dfx/src/util/mod.rs

@@ -31,7 +31,6 @@ pub mod assets;
 pub mod clap;
 pub mod command;
 pub mod currency_conversion;
-pub mod stderr_wrapper;
 pub mod url;
 
 const DECIMAL_POINT: char = '.';