Apply colors only when they are supported (#236, #237)

Author: nikableh

Cargo.lock

@@ -18,6 +18,7 @@ indenter = "0.3.0"
 once_cell = "1.18.0"
 owo-colors = "4.0"
 autocfg = "1.0"
+anstream = "0.6.15"
 
 [profile.dev.package.backtrace]
 opt-level = 3

Cargo.toml

@@ -26,6 +26,7 @@ owo-colors = { workspace = true }
 color-spantrace = { version = "0.2", path = "../color-spantrace", optional = true }
 once_cell = { workspace = true }
 url = { version = "2.1.1", optional = true }
+anstream = { workspace = true }
 
 [dev-dependencies]
 tracing-subscriber = { version = "0.3.0", features = ["env-filter"] }

color-eyre/Cargo.toml

@@ -2,11 +2,12 @@
 //! and error reporting hooks
 use crate::{
     section::PanicMessage,
+    style_if_possible,
     writers::{EnvSection, WriterExt},
 };
 use fmt::Display;
 use indenter::{indented, Format};
-use owo_colors::{style, OwoColorize, Style};
+use owo_colors::{style, Style};
 use std::env;
 use std::fmt::Write as _;
 use std::{fmt, path::PathBuf, sync::Arc};
@@ -192,12 +193,12 @@ impl fmt::Display for StyledFrame<'_> {
         };
 
         if is_dependency_code {
-            write!(f, "{}", (name).style(theme.dependency_code))?;
+            write!(f, "{}", style_if_possible(name, theme.dependency_code))?;
         } else {
-            write!(f, "{}", (name).style(theme.crate_code))?;
+            write!(f, "{}", style_if_possible(name, theme.crate_code))?;
         }
 
-        write!(f, "{}", (hash_suffix).style(theme.code_hash))?;
+        write!(f, "{}", style_if_possible(hash_suffix, theme.code_hash))?;
 
         let mut separated = f.header("\n");
 
@@ -214,8 +215,8 @@ impl fmt::Display for StyledFrame<'_> {
         write!(
             &mut separated.ready(),
             "    at {}:{}",
-            file.style(theme.file),
-            lineno.style(theme.line_number),
+            style_if_possible(file, theme.file),
+            style_if_possible(lineno, theme.line_number),
         )?;
 
         let v = if std::thread::panicking() {
@@ -266,9 +267,9 @@ impl fmt::Display for SourceSection<'_> {
                 write!(
                     &mut f,
                     "{:>8} {} {}",
-                    cur_line_no.style(theme.active_line),
-                    ">".style(theme.active_line),
-                    line.style(theme.active_line),
+                    style_if_possible(cur_line_no, theme.active_line),
+                    style_if_possible(">", theme.active_line),
+                    style_if_possible(line, theme.active_line),
                 )?;
             } else {
                 write!(&mut f, "{:>8} │ {}", cur_line_no, line)?;
@@ -797,7 +798,7 @@ impl PanicMessage for DefaultPanicMessage {
         writeln!(
             f,
             "{}",
-            "The application panicked (crashed).".style(theme.panic_header)
+            style_if_possible("The application panicked (crashed).", theme.panic_header)
         )?;
 
         // Print panic message.
@@ -809,7 +810,7 @@ impl PanicMessage for DefaultPanicMessage {
             .unwrap_or("<non string panic payload>");
 
         write!(f, "Message:  ")?;
-        writeln!(f, "{}", payload.style(theme.panic_message))?;
+        writeln!(f, "{}", style_if_possible(payload, theme.panic_message))?;
 
         // If known, print panic location.
         write!(f, "Location: ")?;
@@ -1131,7 +1132,7 @@ impl fmt::Display for BacktraceFormatter<'_> {
                 write!(
                     &mut separated.ready(),
                     "{:^80}",
-                    buf.style(self.theme.hidden_frames)
+                    style_if_possible(&buf, self.theme.hidden_frames)
                 )?;
             };
         }

color-eyre/src/config.rs

@@ -1,7 +1,6 @@
 //! Module for new types that isolate complext formatting
 use std::fmt;
-
-use owo_colors::OwoColorize;
+use crate::style_if_possible;
 
 pub(crate) struct LocationSection<'a>(
     pub(crate) Option<&'a std::panic::Location<'a>>,
@@ -13,9 +12,9 @@ impl fmt::Display for LocationSection<'_> {
         let theme = self.1;
         // If known, print panic location.
         if let Some(loc) = self.0 {
-            write!(f, "{}", loc.file().style(theme.panic_file))?;
+            write!(f, "{}", style_if_possible(loc.file(), theme.panic_file))?;
             write!(f, ":")?;
-            write!(f, "{}", loc.line().style(theme.panic_line_number))?;
+            write!(f, "{}", style_if_possible(&loc.line(), theme.panic_line_number))?;
         } else {
             write!(f, "<unknown>")?;
         }

color-eyre/src/fmt.rs

@@ -1,6 +1,7 @@
 use crate::{
     config::BacktraceFormatter,
     section::help::HelpInfo,
+    style_if_possible,
     writers::{EnvSection, WriterExt},
     Handler,
 };
@@ -63,7 +64,7 @@ impl eyre::EyreHandler for Handler {
 
         for (n, error) in errors() {
             writeln!(f)?;
-            write!(indented(f).ind(n), "{}", self.theme.error.style(error))?;
+            write!(indented(f).ind(n), "{}", style_if_possible(error, self.theme.error))?;
         }
 
         let mut separated = f.header("\n\n");

color-eyre/src/handler.rs

@@ -359,13 +359,16 @@
 
 use std::sync::Arc;
 
+use anstream::AutoStream;
 use backtrace::Backtrace;
 pub use eyre;
 #[doc(hidden)]
 pub use eyre::Report;
 #[doc(hidden)]
 pub use eyre::Result;
 pub use owo_colors;
+use owo_colors::OwoColorize;
+use owo_colors::Style;
 use section::help::HelpInfo;
 #[doc(hidden)]
 pub use section::Section as Help;
@@ -458,3 +461,17 @@ pub enum ErrorKind<'a> {
 pub fn install() -> Result<(), crate::eyre::Report> {
     config::HookBuilder::default().install()
 }
+
+/// Apply owo_colors style if possible. Returns a string with/without ANSI
+/// escape symbols.
+fn style_if_possible<S>(str: S, style: Style) -> String
+where
+    S: ToString + std::fmt::Display,
+{
+    let color_choice = AutoStream::choice(&std::io::stderr());
+
+    match color_choice {
+        anstream::ColorChoice::Never => str.to_string(),
+        _ => str.style(style).to_string(),
+    }
+}