fmt: report unreadable files and go on with the rest

src/uu/fmt/locales/en-US.ftl

@@ -25,7 +25,7 @@ fmt-error-invalid-tabwidth = Invalid TABWIDTH specification: {$tabwidth}
 fmt-error-first-option-width = invalid option -- {$option}; -WIDTH is recognized only when it is the first
   option; use -w N instead
   Try 'fmt --help' for more information.
-fmt-error-read = read error
+fmt-error-reading-is-directory = error reading {$file}: Is a directory
 fmt-error-invalid-width-malformed = invalid width: {$width}
 fmt-error-cannot-open-for-reading = cannot open {$file} for reading
 fmt-error-cannot-get-metadata = cannot get metadata for {$file}

src/uu/fmt/locales/fr-FR.ftl

@@ -25,7 +25,7 @@ fmt-error-invalid-tabwidth = Spécification TABWIDTH invalide : {$tabwidth}
 fmt-error-first-option-width = option invalide -- {$option} ; -WIDTH n'est reconnu que lorsqu'il est la première
   option ; utilisez -w N à la place
   Essayez 'fmt --help' pour plus d'informations.
-fmt-error-read = erreur de lecture
+fmt-error-reading-is-directory = erreur de lecture de {$file} : C'est un répertoire
 fmt-error-invalid-width-malformed = largeur invalide : {$width}
 fmt-error-cannot-open-for-reading = impossible d'ouvrir {$file} en lecture
 fmt-error-cannot-get-metadata = impossible d'obtenir les métadonnées pour {$file}

src/uu/fmt/src/fmt.rs

@@ -12,6 +12,7 @@ use std::io::{BufReader, BufWriter, Read, Stdout, Write, stdin, stdout};
 use std::path::Path;
 use uucore::display::Quotable;
 use uucore::error::{FromIo, UResult, USimpleError};
+use uucore::show;
 use uucore::translate;
 
 use uucore::format_usage;
@@ -36,8 +37,6 @@ enum FmtError {
     InvalidTabWidth(String),
     #[error("{}", translate!("fmt-error-first-option-width", "option" => .0))]
     FirstOptionWidth(char),
-    #[error("{}", translate!("fmt-error-read"))]
-    ReadError,
     #[error("{}", translate!("fmt-error-invalid-width-malformed", "width" => .0.quote()))]
     InvalidWidthMalformed(String),
 }
@@ -210,16 +209,31 @@ fn process_file(
         Box::new(stdin()) as Box<dyn Read + 'static>
     } else {
         let path = Path::new(file_name);
-        let f = File::open(path).map_err_context(
-            || translate!("fmt-error-cannot-open-for-reading", "file" => path.quote()),
-        )?;
-        if f.metadata()
-            .map_err_context(
-                || translate!("fmt-error-cannot-get-metadata", "file" => path.quote()),
-            )?
-            .is_dir()
-        {
-            return Err(FmtError::ReadError.into());
+        // Like GNU fmt, report a file that can't be read and go on with the next one.
+        let f = match File::open(path) {
+            Ok(f) => f,
+            Err(e) => {
+                show!(e.map_err_context(
+                    || translate!("fmt-error-cannot-open-for-reading", "file" => path.quote())
+                ));
+                return Ok(());
+            }
+        };
+        match f.metadata() {
+            Ok(m) if m.is_dir() => {
+                show!(USimpleError::new(
+                    1,
+                    translate!("fmt-error-reading-is-directory", "file" => path.quote())
+                ));
+                return Ok(());
+            }
+            Ok(_) => {}
+            Err(e) => {
+                show!(e.map_err_context(
+                    || translate!("fmt-error-cannot-get-metadata", "file" => path.quote())
+                ));
+                return Ok(());
+            }
         }
 
         Box::new(f) as Box<dyn Read + 'static>

tests/by-util/test_fmt.rs

@@ -7,7 +7,7 @@
 
 #[cfg(target_os = "linux")]
 use std::os::unix::ffi::OsStringExt;
-use uutests::new_ucmd;
+use uutests::{at_and_ucmd, new_ucmd};
 
 #[test]
 fn test_invalid_arg() {
@@ -253,6 +253,43 @@ fn test_fmt_non_existent_file() {
         .stderr_is("fmt: cannot open 'non-existing' for reading: No such file or directory\n");
 }
 
+// Windows refuses to open a directory as a file, so the error differs there.
+#[cfg(not(windows))]
+#[test]
+fn test_fmt_directory() {
+    let (at, mut ucmd) = at_and_ucmd!();
+    at.mkdir("dir");
+    ucmd.arg("dir")
+        .fails_with_code(1)
+        .no_stdout()
+        .stderr_is("fmt: error reading 'dir': Is a directory\n");
+}
+
+#[cfg(not(windows))]
+#[test]
+fn test_fmt_continues_after_directory() {
+    let (at, mut ucmd) = at_and_ucmd!();
+    at.mkdir("dir");
+    at.write("a.txt", "one\ntwo\n");
+    ucmd.args(&["dir", "non-existing", "a.txt"])
+        .fails_with_code(1)
+        .stdout_is("one two\n")
+        .stderr_is(
+            "fmt: error reading 'dir': Is a directory\n\
+             fmt: cannot open 'non-existing' for reading: No such file or directory\n",
+        );
+}
+
+#[test]
+fn test_fmt_continues_after_missing_file() {
+    let (at, mut ucmd) = at_and_ucmd!();
+    at.write("a.txt", "one\ntwo\n");
+    ucmd.args(&["non-existing", "a.txt"])
+        .fails_with_code(1)
+        .stdout_is("one two\n")
+        .stderr_is("fmt: cannot open 'non-existing' for reading: No such file or directory\n");
+}
+
 #[test]
 fn test_fmt_invalid_goal() {
     for param in ["-g", "--goal"] {