Fix ls relative path and erroring on fake dir (#697)

* Switch to short-names when the path is a relative_path (a dir) and exit with an error if the path does not exist

* Remove debugging print line

* Show relative filenames... It does not work yet for ls ../

* Try something else to fix relative paths... it works, but the ../ code part is not very pretty

* Add canonicalize check and remove code clones

* Fix the canonicalize_with issue pointed out by kubouch. Not sure the prefix_str is what kubouch suggested

* Fix the canonicalize_with issue pointed out by kubouch. Not sure the prefix_str is what kubouch suggested

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

@@ -63,11 +63,18 @@ impl Command for Ls {
         let short_names = call.has_flag("short-names");
 
         let call_span = call.head;
+        // when we're asking for relative paths like ../../, we need to figure out if we need a prefix for display purposes
+        let mut new_prefix = false;
+        let mut prefix_str = PathBuf::new();
 
         let (pattern, prefix) = if let Some(result) =
             call.opt::<Spanned<String>>(engine_state, stack, 0)?
         {
-            let path = PathBuf::from(&result.item);
+            let curr_dir = current_dir(engine_state, stack)?;
+            let path = match nu_path::canonicalize_with(&result.item, curr_dir) {
+                Ok(p) => p,
+                Err(_e) => return Err(ShellError::DirectoryNotFound(result.span)),
+            };
 
             let (mut path, prefix) = if path.is_relative() {
                 let cwd = current_dir(engine_state, stack)?;
@@ -76,7 +83,12 @@ impl Command for Ls {
                 (path, None)
             };
 
-            if path.is_dir() {
+            if path.is_file() {
+                (
+                    path.to_string_lossy().to_string(),
+                    Some(current_dir(engine_state, stack)?),
+                )
+            } else if path.is_dir() {
                 if permission_denied(&path) {
                     #[cfg(unix)]
                     let error_msg = format!(
@@ -98,13 +110,28 @@ impl Command for Ls {
                 if is_empty_dir(&path) {
                     return Ok(PipelineData::new(call_span));
                 }
+                // we figure out how to display a relative path which was requested from a subdirectory, e.g., ls ../
+                let curr_dir = current_dir(engine_state, stack)?;
+                new_prefix = curr_dir.ancestors().any(|x| x.to_path_buf() == path);
+                if new_prefix {
+                    for a in curr_dir.ancestors() {
+                        if a.to_path_buf() == path {
+                            break;
+                        }
+                        prefix_str.push(format!("..{}", std::path::MAIN_SEPARATOR));
+                    }
+                }
 
                 if path.is_dir() {
                     path = path.join("*");
                 }
+                (
+                    path.to_string_lossy().to_string(),
+                    Some(current_dir(engine_state, stack)?),
+                )
+            } else {
+                (path.to_string_lossy().to_string(), prefix)
             }
-
-            (path.to_string_lossy().to_string(), prefix)
         } else {
             let cwd = current_dir(engine_state, stack)?;
             (cwd.join("*").to_string_lossy().to_string(), Some(cwd))
@@ -160,9 +187,27 @@ impl Command for Ls {
 
                     match display_name {
                         Ok(name) => {
-                            let entry =
+                            let filename = if new_prefix {
-                                dir_entry_dict(&path, name, metadata.as_ref(), call_span, long);
+                                match path.file_name() {
-
+                                    Some(p) => {
+                                        format!(
+                                            "{}{}",
+                                            prefix_str.to_string_lossy(),
+                                            p.to_string_lossy()
+                                        )
+                                    }
+                                    None => path.to_string_lossy().to_string(),
+                                }
+                            } else {
+                                name.to_string()
+                            };
+                            let entry = dir_entry_dict(
+                                &path,
+                                filename.as_str(),
+                                metadata.as_ref(),
+                                call_span,
+                                long,
+                            );
                             match entry {
                                 Ok(value) => Some(value),
                                 Err(err) => Some(Value::Error { error: err }),