tr: generate an error if the input is a directory

src/uu/tr/src/operation.rs

@@ -22,7 +22,7 @@ use std::{
     io::{BufRead, Write},
     ops::Not,
 };
-use uucore::error::UError;
+use uucore::error::{UError, UResult, USimpleError};
 
 #[derive(Debug, Clone)]
 pub enum BadSequence {
@@ -577,15 +577,25 @@ impl SymbolTranslator for SqueezeOperation {
     }
 }
 
-pub fn translate_input<T, R, W>(input: &mut R, output: &mut W, mut translator: T)
+pub fn translate_input<T, R, W>(input: &mut R, output: &mut W, mut translator: T) -> UResult<()>
 where
     T: SymbolTranslator,
     R: BufRead,
     W: Write,
 {
     let mut buf = Vec::new();
     let mut output_buf = Vec::new();
-    while let Ok(length) = input.read_until(b'\n', &mut buf) {
+    loop {
+        let length = match input.read_until(b'\n', &mut buf) {
+            Ok(0) => break, // EOF reached
+            Ok(n) => n,
+            Err(e) => {
+                return Err(USimpleError::new(
+                    1,
+                    format!("{}: read error: {}", uucore::util_name(), e),
+                ));
+            }
+        };
         if length == 0 {
             break;
         } else {
@@ -596,4 +606,5 @@ where
         buf.clear();
         output_buf.clear();
     }
+    Ok(())
 }

src/uu/tr/src/tr.rs

@@ -132,24 +132,24 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
             let delete_op = DeleteOperation::new(set1);
             let squeeze_op = SqueezeOperation::new(set2);
             let op = delete_op.chain(squeeze_op);
-            translate_input(&mut locked_stdin, &mut buffered_stdout, op);
+            translate_input(&mut locked_stdin, &mut buffered_stdout, op)?;
         } else {
             let op = DeleteOperation::new(set1);
-            translate_input(&mut locked_stdin, &mut buffered_stdout, op);
+            translate_input(&mut locked_stdin, &mut buffered_stdout, op)?;
         }
     } else if squeeze_flag {
         if sets_len < 2 {
             let op = SqueezeOperation::new(set1);
-            translate_input(&mut locked_stdin, &mut buffered_stdout, op);
+            translate_input(&mut locked_stdin, &mut buffered_stdout, op)?;
         } else {
             let translate_op = TranslateOperation::new(set1, set2.clone())?;
             let squeeze_op = SqueezeOperation::new(set2);
             let op = translate_op.chain(squeeze_op);
-            translate_input(&mut locked_stdin, &mut buffered_stdout, op);
+            translate_input(&mut locked_stdin, &mut buffered_stdout, op)?;
         }
     } else {
         let op = TranslateOperation::new(set1, set2)?;
-        translate_input(&mut locked_stdin, &mut buffered_stdout, op);
+        translate_input(&mut locked_stdin, &mut buffered_stdout, op)?;
     }
     Ok(())
 }

tests/by-util/test_tr.rs

@@ -13,6 +13,11 @@ fn test_invalid_arg() {
     new_ucmd!().arg("--definitely-invalid").fails().code_is(1);
 }
 
+#[test]
+fn test_invalid_input() {
+    new_ucmd!().args(&["1", "1", "<", "."]).fails().code_is(1);
+}
+
 #[test]
 fn test_to_upper() {
     new_ucmd!()