install: fixes issue uutils#7795

Author: zcg00

src/uu/install/src/install.rs

@@ -13,7 +13,7 @@ use filetime::{FileTime, set_file_times};
 use std::fmt::Debug;
 use std::fs::File;
 use std::fs::{self, metadata};
-use std::path::{MAIN_SEPARATOR, Path, PathBuf};
+use std::path::{self, Path, PathBuf, MAIN_SEPARATOR};
 use std::process;
 use thiserror::Error;
 use uucore::backup_control::{self, BackupMode};
@@ -101,6 +101,9 @@ enum InstallError {
 
     #[error("cannot overwrite directory {} with non-directory {}", .0.quote(), .1.quote())]
     OverrideDirectoryFailed(PathBuf, PathBuf),
+
+    #[error("'{0}' and '{1}' are the same file")]
+    SameFile(PathBuf, PathBuf),
 }
 
 impl UError for InstallError {
@@ -751,6 +754,10 @@ 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 path::absolute(from)? == path::absolute(to)? {
+        return Err(InstallError::SameFile(from.to_path_buf(), to.to_path_buf()).into());
+    }
+
     if to.is_dir() && !from.is_dir() {
         return Err(InstallError::OverrideDirectoryFailed(
             to.to_path_buf().clone(),

tests/by-util/test_install.rs

@@ -1778,3 +1778,15 @@ fn test_install_failing_copy_file_to_target_contain_subdir_with_same_name() {
         .fails()
         .stderr_contains("cannot overwrite directory");
 }
+
+#[test]
+fn test_install_same_file() {
+    let (at, mut ucmd) = at_and_ucmd!();
+    let file = "file";
+
+    at.touch(file);
+    ucmd.arg(file)
+        .arg(".")
+        .fails()
+        .stderr_contains("'file' and './file' are the same file");
+}