ptx: Flush BufWriter, add context to errors

src/uu/ptx/src/ptx.rs

@@ -633,7 +633,8 @@ fn write_traditional_output(
     let mut writer: BufWriter<Box<dyn Write>> = BufWriter::new(if output_filename == "-" {
         Box::new(stdout())
     } else {
-        let file = File::create(output_filename).map_err_context(String::new)?;
+        let file = File::create(output_filename)
+            .map_err_context(|| output_filename.maybe_quote().to_string())?;
         Box::new(file)
     });
 
@@ -673,8 +674,11 @@ fn write_traditional_output(
                 return Err(PtxError::DumbFormat.into());
             }
         };
-        writeln!(writer, "{output_line}").map_err_context(String::new)?;
+        writeln!(writer, "{output_line}").map_err_context(|| "write failed".into())?;
     }
+
+    writer.flush().map_err_context(|| "write failed".into())?;
+
     Ok(())
 }
 

tests/by-util/test_ptx.rs

@@ -163,3 +163,14 @@ fn test_format() {
         .succeeds()
         .stdout_only("\\xx {}{}{a}{}{}\n");
 }
+
+#[cfg(target_os = "linux")]
+#[test]
+fn test_failed_write_is_reported() {
+    new_ucmd!()
+        .arg("-G")
+        .pipe_in("hello")
+        .set_stdout(std::fs::File::create("/dev/full").unwrap())
+        .fails()
+        .stderr_is("ptx: write failed: No space left on device\n");
+}