add -n for path expand, so it doesn't follow symlink (#6255)

* add -p for path expand, so it doesn't follow symlink

* fix arg name

* rename from no-dereferenct to no-follow-link

* rename from no-follow-link to no-symlink, and change short -p to -n

* follow strict first

* fix

* simplify test

* fix clippy

* fix test on windows

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

@@ -57,9 +57,9 @@ impl Command for Cp {
             // .switch("force", "suppress error when no file", Some('f'))
             .switch("interactive", "ask user to confirm action", Some('i'))
             .switch(
-                "no-dereference",
-                "If the -r option is specified, no symbolic links are followed.",
-                Some('p'),
+                "no-symlink",
+                "no symbolic links are followed, only works if -r is active",
+                Some('n'),
             )
             .category(Category::FileSystem)
     }
@@ -218,7 +218,7 @@ impl Command for Cp {
                     )
                 })?;
 
-                let not_follow_symlink = call.has_flag("no-dereference");
+                let not_follow_symlink = call.has_flag("no-symlink");
                 let sources = sources.paths_applying_with(|(source_file, depth_level)| {
                     let mut dest = destination.clone();
 

crates/nu-command/src/path/expand.rs

@@ -11,6 +11,7 @@ struct Arguments {
     strict: bool,
     columns: Option<Vec<String>>,
     cwd: String,
+    not_follow_symlink: bool,
 }
 
 impl PathSubcommandArguments for Arguments {
@@ -34,6 +35,7 @@ impl Command for SubCommand {
                 "Throw an error if the path could not be expanded",
                 Some('s'),
             )
+            .switch("no-symlink", "Do not resolve symbolic links", Some('n'))
             .named(
                 "columns",
                 SyntaxShape::Table,
@@ -58,6 +60,7 @@ impl Command for SubCommand {
             strict: call.has_flag("strict"),
             columns: call.get_flag(engine_state, stack, "columns")?,
             cwd: current_dir_str(engine_state, stack)?,
+            not_follow_symlink: call.has_flag("no-symlink"),
         };
 
         input.map(
@@ -84,6 +87,11 @@ impl Command for SubCommand {
                 example: r"'foo\..\bar' | path expand",
                 result: None,
             },
+            Example {
+                description: "Expand an absolute path without following symlink",
+                example: r"'foo\..\bar' | path expand -n",
+                result: None,
+            },
         ]
     }
 
@@ -110,10 +118,16 @@ impl Command for SubCommand {
 }
 
 fn expand(path: &Path, span: Span, args: &Arguments) -> Value {
-    if let Ok(p) = canonicalize_with(path, &args.cwd) {
+    if args.strict {
+        match canonicalize_with(path, &args.cwd) {
+            Ok(p) => {
+                if args.not_follow_symlink {
+                    Value::string(expand_path_with(path, &args.cwd).to_string_lossy(), span)
+                } else {
                     Value::string(p.to_string_lossy(), span)
-    } else if args.strict {
-        Value::Error {
+                }
+            }
+            Err(_) => Value::Error {
                 error: ShellError::GenericError(
                     "Could not expand path".into(),
                     "could not be expanded (path might not exist, non-final \
@@ -123,9 +137,16 @@ fn expand(path: &Path, span: Span, args: &Arguments) -> Value {
                     None,
                     Vec::new(),
                 ),
+            },
         }
-    } else {
+    } else if args.not_follow_symlink {
         Value::string(expand_path_with(path, &args.cwd).to_string_lossy(), span)
+    } else {
+        canonicalize_with(path, &args.cwd)
+            .map(|p| Value::string(p.to_string_lossy(), span))
+            .unwrap_or_else(|_| {
+                Value::string(expand_path_with(path, &args.cwd).to_string_lossy(), span)
+            })
     }
 }
 

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

@@ -286,7 +286,7 @@ fn copy_dir_contains_symlink() {
         // make symbolic link and copy.
         nu!(
             cwd: sandbox.cwd(),
-            "rm tmp_dir/good_bye; cp -r -p tmp_dir tmp_dir_2",
+            "rm tmp_dir/good_bye; cp -r -n tmp_dir tmp_dir_2",
         );
 
         // check hello_there exists inside `tmp_dir_2`, and `dangle_symlink` also exists inside `tmp_dir_2`.
@@ -309,7 +309,7 @@ fn copy_dir_symlink_file_body_not_changed() {
         // make symbolic link and copy.
         nu!(
             cwd: sandbox.cwd(),
-            "rm tmp_dir/good_bye; cp -r -p tmp_dir tmp_dir_2; rm -r tmp_dir; cp -r -p tmp_dir_2 tmp_dir; echo hello_data | save tmp_dir/good_bye",
+            "rm tmp_dir/good_bye; cp -r -n tmp_dir tmp_dir_2; rm -r tmp_dir; cp -r -n tmp_dir_2 tmp_dir; echo hello_data | save tmp_dir/good_bye",
         );
 
         // check dangle_symlink in tmp_dir is no longer dangling.

crates/nu-command/tests/commands/path/expand.rs

@@ -24,6 +24,28 @@ fn expands_path_with_dot() {
     })
 }
 
+#[cfg(unix)]
+#[test]
+fn expands_path_without_follow_symlink() {
+    Playground::setup("path_expand_3", |dirs, sandbox| {
+        sandbox
+            .within("menu")
+            .with_files(vec![EmptyFile("spam.txt")]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                ln -s spam.txt menu/spam_link.ln;
+                echo "menu/./spam_link.ln"
+                | path expand -n
+            "#
+        ));
+
+        let expected = dirs.test.join("menu").join("spam_link.ln");
+        assert_eq!(PathBuf::from(actual.out), expected);
+    })
+}
+
 #[test]
 fn expands_path_with_double_dot() {
     Playground::setup("path_expand_2", |dirs, sandbox| {
@@ -75,4 +97,31 @@ mod windows {
             assert!(!PathBuf::from(actual.out).starts_with("~"));
         })
     }
+
+    #[test]
+    fn expands_path_without_follow_symlink() {
+        Playground::setup("path_expand_3", |dirs, sandbox| {
+            sandbox
+                .within("menu")
+                .with_files(vec![EmptyFile("spam.txt")]);
+
+            let cwd = dirs.test();
+            std::os::windows::fs::symlink_file(
+                cwd.join("menu").join("spam.txt"),
+                cwd.join("menu").join("spam_link.ln"),
+            )
+            .unwrap();
+
+            let actual = nu!(
+                cwd: dirs.test(), pipeline(
+                r#"
+                echo "menu/./spam_link.ln"
+                | path expand -n
+            "#
+            ));
+
+            let expected = dirs.test.join("menu").join("spam_link.ln");
+            assert_eq!(PathBuf::from(actual.out), expected);
+        })
+    }
 }