Fix cp -u/mv -u when the dst doesn't exist (#9662)

Fixes #9655

crates/nu-command/src/filesystem/cp.rs

@@ -184,7 +184,7 @@ impl Command for Cp {
                             canonicalize_with(dst.as_path(), &current_dir_path).unwrap_or(dst);
 
                         // ignore when source file is not newer than target file
-                        if update_mode && super::util::is_older(&src, &dst) {
+                        if update_mode && super::util::is_older(&src, &dst).unwrap_or(false) {
                             continue;
                         }
 

crates/nu-command/src/filesystem/mv.rs

@@ -313,7 +313,7 @@ fn move_file(
         }
     }
 
-    if update_mode && super::util::is_older(&from, &to) {
+    if update_mode && super::util::is_older(&from, &to).unwrap_or(false) {
         Ok(false)
     } else {
         match move_item(&from, from_span, &to) {

crates/nu-command/src/filesystem/util.rs

@@ -133,9 +133,11 @@ fn get_interactive_confirmation(prompt: String) -> Result<bool, Box<dyn Error>>
     }
 }
 
-pub fn is_older(src: &Path, dst: &Path) -> bool {
-    if !dst.exists() {
-        return true;
+/// Return `Some(true)` if the last change time of the `src` old than the `dst`,  
+/// otherwisie return `Some(false)`. Return `None` if the `src` or `dst` doesn't exist.
+pub fn is_older(src: &Path, dst: &Path) -> Option<bool> {
+    if !dst.exists() || !src.exists() {
+        return None;
     }
     #[cfg(unix)]
     {
@@ -146,7 +148,7 @@ pub fn is_older(src: &Path, dst: &Path) -> bool {
         let dst_ctime = std::fs::metadata(dst)
             .map(|m| m.ctime())
             .unwrap_or(i64::MAX);
-        src_ctime <= dst_ctime
+        Some(src_ctime <= dst_ctime)
     }
     #[cfg(windows)]
     {
@@ -157,7 +159,7 @@ pub fn is_older(src: &Path, dst: &Path) -> bool {
         let dst_ctime = std::fs::metadata(dst)
             .map(|m| m.last_write_time())
             .unwrap_or(u64::MAX);
-        src_ctime <= dst_ctime
+        Some(src_ctime <= dst_ctime)
     }
 }
 

crates/nu-command/tests/commands/cp.rs

@@ -607,5 +607,9 @@ fn copy_file_with_update_flag_impl(progress: bool) {
         sandbox.with_files(vec![FileWithContent("newest_valid.txt", "newest_body")]);
         let actual = nu!(cwd: sandbox.cwd(), "cp {} -u newest_valid.txt valid.txt; open valid.txt", progress_flag);
         assert_eq!(actual.out, "newest_body");
+
+        // when destination doesn't exist
+        let actual = nu!(cwd: sandbox.cwd(), "cp {} -u newest_valid.txt des_missing.txt; open des_missing.txt", progress_flag);
+        assert_eq!(actual.out, "newest_body");
     });
 }

crates/nu-command/tests/commands/move_/mv.rs

@@ -484,5 +484,10 @@ fn mv_with_update_flag() {
         sandbox.with_files(vec![FileWithContent("newest_valid.txt", "newest_body")]);
         let actual = nu!(cwd: sandbox.cwd(), "mv -uf newest_valid.txt valid.txt; open valid.txt");
         assert_eq!(actual.out, "newest_body");
+
+        // when destination doesn't exist
+        sandbox.with_files(vec![FileWithContent("newest_valid.txt", "newest_body")]);
+        let actual = nu!(cwd: sandbox.cwd(), "mv -uf newest_valid.txt des_missing.txt; open des_missing.txt");
+        assert_eq!(actual.out, "newest_body");
     });
 }