Merge pull request #2437 from miDeb/cp/reflink-auto

cp: default to --reflink=auto on linux and macos

src/uu/cp/src/cp.rs

@@ -667,8 +667,15 @@ impl Options {
                         }
                     }
                 } else {
+                    #[cfg(any(target_os = "linux", target_os = "macos"))]
+                    {
+                        ReflinkMode::Auto
+                    }
+                    #[cfg(not(any(target_os = "linux", target_os = "macos")))]
+                    {
                         ReflinkMode::Never
                     }
+                }
             },
             backup: backup_mode,
             backup_suffix,
@@ -1218,28 +1225,39 @@ fn copy_file(source: &Path, dest: &Path, options: &Options) -> CopyResult<()> {
 /// Copy the file from `source` to `dest` either using the normal `fs::copy` or a
 /// copy-on-write scheme if --reflink is specified and the filesystem supports it.
 fn copy_helper(source: &Path, dest: &Path, options: &Options) -> CopyResult<()> {
-    if options.reflink_mode != ReflinkMode::Never {
-        #[cfg(not(any(target_os = "linux", target_os = "macos")))]
-        return Err("--reflink is only supported on linux and macOS"
-            .to_string()
-            .into());
-
-        #[cfg(target_os = "macos")]
-        copy_on_write_macos(source, dest, options.reflink_mode)?;
-        #[cfg(target_os = "linux")]
-        copy_on_write_linux(source, dest, options.reflink_mode)?;
-    } else if !options.dereference && fs::symlink_metadata(&source)?.file_type().is_symlink() {
-        copy_link(source, dest)?;
-    } else if source.to_string_lossy() == "/dev/null" {
-        /* workaround a limitation of fs::copy
-         * https://github.com/rust-lang/rust/issues/79390
-         */
-        File::create(dest)?;
-    } else {
     if options.parents {
         let parent = dest.parent().unwrap_or(dest);
         fs::create_dir_all(parent)?;
     }
+    let is_symlink = fs::symlink_metadata(&source)?.file_type().is_symlink();
+    if source.to_string_lossy() == "/dev/null" {
+        /* workaround a limitation of fs::copy
+         * https://github.com/rust-lang/rust/issues/79390
+         */
+        File::create(dest)?;
+    } else if !options.dereference && is_symlink {
+        copy_link(source, dest)?;
+    } else if options.reflink_mode != ReflinkMode::Never {
+        #[cfg(not(any(target_os = "linux", target_os = "macos")))]
+        return Err("--reflink is only supported on linux and macOS"
+            .to_string()
+            .into());
+        #[cfg(any(target_os = "linux", target_os = "macos"))]
+        if is_symlink {
+            assert!(options.dereference);
+            let real_path = std::fs::read_link(source)?;
+
+            #[cfg(target_os = "macos")]
+            copy_on_write_macos(&real_path, dest, options.reflink_mode)?;
+            #[cfg(target_os = "linux")]
+            copy_on_write_linux(&real_path, dest, options.reflink_mode)?;
+        } else {
+            #[cfg(target_os = "macos")]
+            copy_on_write_macos(source, dest, options.reflink_mode)?;
+            #[cfg(target_os = "linux")]
+            copy_on_write_linux(source, dest, options.reflink_mode)?;
+        }
+    } else {
         fs::copy(source, dest).context(&*context_for(source, dest))?;
     }
 
@@ -1259,6 +1277,11 @@ fn copy_link(source: &Path, dest: &Path) -> CopyResult<()> {
             ),
         }
     } else {
+        // we always need to remove the file to be able to create a symlink,
+        // even if it is writeable.
+        if dest.exists() {
+            fs::remove_file(dest)?;
+        }
         dest.into()
     };
     symlink_file(&link, &dest, &*context_for(&link, &dest))

tests/by-util/test_cp.rs

@@ -1325,3 +1325,16 @@ fn test_copy_dir_with_symlinks() {
     ucmd.args(&["-r", "dir", "copy"]).succeeds();
     assert_eq!(at.resolve_link("copy/file-link"), "file");
 }
+
+#[test]
+#[cfg(not(windows))]
+fn test_copy_symlink_force() {
+    let (at, mut ucmd) = at_and_ucmd!();
+    at.touch("file");
+    at.symlink_file("file", "file-link");
+    at.touch("copy");
+
+    ucmd.args(&["file-link", "copy", "-f", "--no-dereference"])
+        .succeeds();
+    assert_eq!(at.resolve_link("copy"), "file");
+}