Fix panic when printing the help, version, or specification output fails

bin/CHANGELOG.md

@@ -4,6 +4,7 @@
 
 ### Patch
 
+- Fix panic when printing the help, version, or specification output fails
 - Fix panic when the block value is too large
 - Fix inaccurate error positions when decoding by small blocks with ignored characters
 - Fix panic when the width value is not a multiple of the base or is too large

bin/src/main.rs

@@ -14,6 +14,14 @@ macro_rules! check {
     };
 }
 
+macro_rules! println {
+    ($($x:tt)*) => {{
+        let mut stdout = std::io::stdout();
+        let result = writeln!(stdout, $($x)*).map_err(Error::Write);
+        result.and_then(|()| stdout.flush().map_err(Error::Write))
+    }};
+}
+
 #[derive(Debug)]
 pub enum Error {
     ParseOpts(getopts::Fail),
@@ -227,7 +235,7 @@ fn wrapped_main(program: &str, args: Vec<String>) -> Result<()> {
             r"Usage: {program} --mode=<mode> --base=<base> [<options>]
 Usage: {program} --mode=<mode> --symbols=<symbols> [<options>]"
         );
-        print!(
+        return println!(
             "{0}
 Examples:
     # Using the RFC4648 base64 encoding
@@ -246,17 +254,14 @@ Examples:
     {1} --mode=decode \\
         --symbols=0123456789bcdfghjklmnpqrstuvwxyz \\
         --translate=BCDFGHJKLMNPQRSTUVWXYZbcdfghjklmnpqrstuvwxyz \\
-        --least_significant_bit_first
-",
+        --least_significant_bit_first",
             opts.usage(&brief),
             program
         );
-        return Ok(());
     }
 
     if args.len() == 1 && (args[0] == "--version" || args[0] == "-v") {
-        println!("{}", env!("CARGO_PKG_VERSION"));
-        return Ok(());
+        return println!("{}", env!("CARGO_PKG_VERSION"));
     }
 
     let matches = opts.parse(&args).map_err(Error::ParseOpts)?;
@@ -324,10 +329,7 @@ Examples:
         "" => return Err(Error::Cmdline("Empty mode".into())),
         x if "encode".starts_with(x) => true,
         x if "decode".starts_with(x) => false,
-        x if "specification".starts_with(x) => {
-            println!("{:#?}", base.specification());
-            return Ok(());
-        }
+        x if "specification".starts_with(x) => return println!("{:#?}", base.specification()),
         _ => return Err(Error::Cmdline("Invalid mode".into())),
     };
 

bin/test.sh

@@ -119,6 +119,9 @@ if [ -e /dev/full ]; then
     'Write error: No space left on device (os error 28)'
   unit '-md -b64 -p= -o /dev/full' Zm9v '' \
     'Write error: No space left on device (os error 28)'
+  unit '-ms -b64 >/dev/full' '' '' 'Write error: No space left on device (os error 28)'
+  unit '--version >/dev/full' '' '' 'Write error: No space left on device (os error 28)'
+  unit '--help >/dev/full' '' '' 'Write error: No space left on device (os error 28)'
 fi
 echo
 echo -n 'custom:'