cp: refuse to copy symlink over itself

dan-hipschman · dan-hipschman · commit a43a2ff12af4 · 2025-04-11T12:50:42.000-07:00
diff --git a/src/uu/cp/src/cp.rs b/src/uu/cp/src/cp.rs
@@ -1808,7 +1808,11 @@ fn is_forbidden_to_copy_to_same_file(
     if options.copy_mode == CopyMode::SymLink && dest_is_symlink {
         return false;
     }
-    if dest_is_symlink && source_is_symlink && !options.dereference {
+    if dest_is_symlink
+        && source_is_symlink
+        && source.file_name() != dest.file_name()
+        && !options.dereference
+    {
         return false;
     }
     true
diff --git a/tests/by-util/test_cp.rs b/tests/by-util/test_cp.rs
@@ -5217,6 +5217,31 @@ mod same_file {
         assert_eq!(symlink1, at.resolve_link(symlink2));
     }
 
+    #[test]
+    fn test_same_symlink_to_itself_no_dereference() {
+        let scene = TestScenario::new(util_name!());
+        let at = &scene.fixtures;
+        at.write(FILE_NAME, CONTENTS);
+        at.symlink_file(FILE_NAME, SYMLINK_NAME);
+        scene
+            .ucmd()
+            .args(&["-P", SYMLINK_NAME, SYMLINK_NAME])
+            .fails()
+            .stderr_contains("are the same file");
+    }
+
+    #[test]
+    fn test_same_dangling_symlink_to_itself_no_dereference() {
+        let scene = TestScenario::new(util_name!());
+        let at = &scene.fixtures;
+        at.symlink_file("nonexistent_file", SYMLINK_NAME);
+        scene
+            .ucmd()
+            .args(&["-P", SYMLINK_NAME, SYMLINK_NAME])
+            .fails()
+            .stderr_contains("are the same file");
+    }
+
     // the following tests tries to copy file to a hardlink of the same file with
     // various options
     #[test]

Original file line number	Diff line number	Diff line change
`@@ -1808,7 +1808,11 @@ fn is_forbidden_to_copy_to_same_file(`
`1808`	`1808`	`if options.copy_mode == CopyMode::SymLink && dest_is_symlink {`
`1809`	`1809`	`return false;`
`1810`	`1810`	`}`
`1811`		`- if dest_is_symlink && source_is_symlink && !options.dereference {`
	`1811`	`+ if dest_is_symlink`
	`1812`	`+ && source_is_symlink`
	`1813`	`+ && source.file_name() != dest.file_name()`
	`1814`	`+ && !options.dereference`
	`1815`	`+ {`
`1812`	`1816`	`return false;`
`1813`	`1817`	`}`
`1814`	`1818`	`true`