fix: panics on redirect to /dev/full

src/cmp.rs

@@ -3,6 +3,7 @@
 // For the full copyright and license information, please view the LICENSE-*
 // files that was distributed with this source code.
 
+use crate::safe_println;
 use crate::utils::format_failure_to_read_input_file;
 use std::env::{self, ArgsOs};
 use std::ffi::OsString;
@@ -721,7 +722,7 @@ fn report_difference(
             format_visible_byte(to_byte)
         );
     }
-    println!();
+    safe_println!();
 }
 
 #[cfg(test)]

src/diff.rs

@@ -91,7 +91,7 @@ pub fn main(opts: Peekable<ArgsOs>) -> ExitCode {
             params.to.to_string_lossy()
         );
     } else {
-        io::stdout().write_all(&result).unwrap();
+        let _ = io::stdout().write_all(&result);
     }
     if result.is_empty() {
         maybe_report_identical_files();

src/macros.rs

@@ -23,3 +23,15 @@ macro_rules! assert_diff_eq {
         assert_eq!(actual, $expected);
     }};
 }
+
+/// A safe version of println!() that does not panic if stdout is redirected to /dev/full
+#[macro_export]
+macro_rules! safe_println {
+    () => {
+        let _ = ::std::io::Write::write_all(&mut ::std::io::stdout(), b"\n");
+    };
+    ($($arg:tt)*) => {
+        let _ = ::std::io::Write::write_fmt(&mut ::std::io::stdout(), format_args!($($arg)*))
+            .and_then(|_| ::std::io::Write::write_all(&mut ::std::io::stdout(), b"\n"));
+    };
+}

src/main.rs

@@ -40,10 +40,10 @@ fn name(binary_path: &Path) -> &OsStr {
 const VERSION: &str = env!("CARGO_PKG_VERSION");
 
 fn usage(name: &str) {
-    println!("{name} {VERSION} (multi-call binary)\n");
-    println!("Usage: {name} [function [arguments...]]\n");
-    println!("Currently defined functions:\n");
-    println!("    cmp, diff\n");
+    safe_println!("{name} {VERSION} (multi-call binary)\n");
+    safe_println!("Usage: {name} [function [arguments...]]\n");
+    safe_println!("Currently defined functions:\n");
+    safe_println!("    cmp, diff\n");
 }
 
 fn second_arg_error(name: &OsStr) -> ! {