install: improve error message (#7794)

* friendly message install file to directory containing directory with same name

* install: test install file to directory containing directory with same name

src/uu/install/src/install.rs

@@ -98,6 +98,9 @@ enum InstallError {
 
     #[error("failed to access {}: Not a directory", .0.quote())]
     NotADirectory(PathBuf),
+
+    #[error("cannot overwrite directory {} with non-directory {}", .0.quote(), .1.quote())]
+    OverrideDirectoryFailed(PathBuf, PathBuf),
 }
 
 impl UError for InstallError {
@@ -748,6 +751,13 @@ fn copy_normal_file(from: &Path, to: &Path) -> UResult<()> {
 /// Returns an empty Result or an error in case of failure.
 ///
 fn copy_file(from: &Path, to: &Path) -> UResult<()> {
+    if to.is_dir() && !from.is_dir() {
+        return Err(InstallError::OverrideDirectoryFailed(
+            to.to_path_buf().clone(),
+            from.to_path_buf().clone(),
+        )
+        .into());
+    }
     // fs::copy fails if destination is a invalid symlink.
     // so lets just remove all existing files at destination before copy.
     if let Err(e) = fs::remove_file(to) {

tests/by-util/test_install.rs

@@ -1764,3 +1764,17 @@ fn test_install_from_stdin() {
     assert!(at.file_exists(target));
     assert_eq!(at.read(target), test_string);
 }
+
+#[test]
+fn test_install_failing_copy_file_to_target_contain_subdir_with_same_name() {
+    let (at, mut ucmd) = at_and_ucmd!();
+    let file = "file";
+    let dir1 = "dir1";
+
+    at.touch(file);
+    at.mkdir_all(&format!("{dir1}/{file}"));
+    ucmd.arg(file)
+        .arg(dir1)
+        .fails()
+        .stderr_contains("cannot overwrite directory");
+}