Merge pull request uutils#2886 from jfinkels/tail-io-error

tail: improve error handling when file not found

src/uu/tail/src/tail.rs

@@ -30,7 +30,7 @@ use std::path::Path;
 use std::thread::sleep;
 use std::time::Duration;
 use uucore::display::Quotable;
-use uucore::error::{UResult, USimpleError};
+use uucore::error::{FromIo, UResult, USimpleError};
 use uucore::parse_size::{parse_size, ParseSizeError};
 use uucore::ringbuffer::RingBuffer;
 
@@ -220,7 +220,8 @@ fn uu_tail(settings: &Settings) -> UResult<()> {
             if path.is_dir() {
                 continue;
             }
-            let mut file = File::open(&path).unwrap();
+            let mut file = File::open(&path)
+                .map_err_context(|| format!("cannot open {} for reading", filename.quote()))?;
             let md = file.metadata().unwrap();
             if is_seekable(&mut file) && get_block_size(&md) > 0 {
                 bounded_tail(&mut file, settings);

tests/by-util/test_tail.rs

@@ -3,7 +3,7 @@
 //  * For the full copyright and license information, please view the LICENSE
 //  * file that was distributed with this source code.
 
-// spell-checker:ignore (ToDO) abcdefghijklmnopqrstuvwxyz efghijklmnopqrstuvwxyz vwxyz emptyfile
+// spell-checker:ignore (ToDO) abcdefghijklmnopqrstuvwxyz efghijklmnopqrstuvwxyz vwxyz emptyfile bogusfile
 
 extern crate tail;
 
@@ -475,3 +475,12 @@ fn test_tail_bytes_for_funny_files() {
             .code_is(exp_result.code());
     }
 }
+
+#[test]
+fn test_no_such_file() {
+    new_ucmd!()
+        .arg("bogusfile")
+        .fails()
+        .no_stdout()
+        .stderr_contains("cannot open 'bogusfile' for reading: No such file or directory");
+}