From 746a7b14d03f32fb0db6e951b46cbbd3003c5ff7 Mon Sep 17 00:00:00 2001
From: SaHHiiLL <87093947+SaHHiiLL@users.noreply.github.com>
Date: Fri, 19 Jan 2024 14:39:00 +0000
Subject: [PATCH] tsort: returns error when input is dir - same as GNU tsort
 (#5860)

* fix: return error when input is dir

* test: when tsort is given a dir

* fix: do not need to mention tsort in error message

* test: using concrete directory name

* tsort: fix formatting in test

---------

Co-authored-by: Daniel Hofstetter <daniel.hofstetter@42dh.com>
---
 src/uu/tsort/src/tsort.rs   | 9 ++++++++-
 tests/by-util/test_tsort.rs | 9 +++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/src/uu/tsort/src/tsort.rs b/src/uu/tsort/src/tsort.rs
index 3ae4f4f97..2bc9d3175 100644
--- a/src/uu/tsort/src/tsort.rs
+++ b/src/uu/tsort/src/tsort.rs
@@ -32,7 +32,14 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
         stdin_buf = stdin();
         &mut stdin_buf as &mut dyn Read
     } else {
-        file_buf = File::open(Path::new(&input)).map_err_context(|| input.to_string())?;
+        let path = Path::new(&input);
+        if path.is_dir() {
+            return Err(USimpleError::new(
+                1,
+                format!("{}: read error: Is a directory", input),
+            ));
+        }
+        file_buf = File::open(path).map_err_context(|| input.to_string())?;
         &mut file_buf as &mut dyn Read
     });
 
diff --git a/tests/by-util/test_tsort.rs b/tests/by-util/test_tsort.rs
index 188894516..79195efa2 100644
--- a/tests/by-util/test_tsort.rs
+++ b/tests/by-util/test_tsort.rs
@@ -64,3 +64,12 @@ fn test_multiple_arguments() {
         .fails()
         .stderr_contains("unexpected argument 'invalid_file' found");
 }
+
+#[test]
+fn test_error_on_dir() {
+    let (at, mut ucmd) = at_and_ucmd!();
+    at.mkdir("tsort_test_dir");
+    ucmd.arg("tsort_test_dir")
+        .fails()
+        .stderr_contains("tsort: tsort_test_dir: read error: Is a directory");
+}