From 159cf27e39322e0c3b28beec9214b972dc8757a2 Mon Sep 17 00:00:00 2001
From: Odin Dutton <odindutton@gmail.com>
Date: Sun, 8 Sep 2019 15:10:08 +1000
Subject: [PATCH] Implement `cd -` to return to the last path for the
 FilesystemShell

---
 src/shell/filesystem_shell.rs | 25 +++++++++++++++++++++++--
 tests/command_cd_tests.rs     | 34 ++++++++++++++++++++++++++++++++++
 2 files changed, 57 insertions(+), 2 deletions(-)

diff --git a/src/shell/filesystem_shell.rs b/src/shell/filesystem_shell.rs
index 1bb7796b5d..5908784640 100644
--- a/src/shell/filesystem_shell.rs
+++ b/src/shell/filesystem_shell.rs
@@ -15,6 +15,7 @@ use std::path::{Path, PathBuf};
 
 pub struct FilesystemShell {
     pub(crate) path: String,
+    last_path: String,
     completer: NuCompleter,
     hinter: HistoryHinter,
 }
@@ -29,6 +30,7 @@ impl Clone for FilesystemShell {
     fn clone(&self) -> Self {
         FilesystemShell {
             path: self.path.clone(),
+            last_path: self.path.clone(),
             completer: NuCompleter {
                 file_completer: FilenameCompleter::new(),
                 commands: self.completer.commands.clone(),
@@ -44,6 +46,7 @@ impl FilesystemShell {
 
         Ok(FilesystemShell {
             path: path.to_string_lossy().to_string(),
+            last_path: path.to_string_lossy().to_string(),
             completer: NuCompleter {
                 file_completer: FilenameCompleter::new(),
                 commands,
@@ -56,8 +59,10 @@ impl FilesystemShell {
         path: String,
         commands: CommandRegistry,
     ) -> Result<FilesystemShell, std::io::Error> {
+        let last_path = path.clone();
         Ok(FilesystemShell {
             path,
+            last_path,
             completer: NuCompleter {
                 file_completer: FilenameCompleter::new(),
                 commands,
@@ -182,14 +187,29 @@ impl Shell for FilesystemShell {
             Some(v) => {
                 let target = v.as_path()?;
                 let path = PathBuf::from(self.path());
-                match dunce::canonicalize(path.join(target).as_path()) {
+                match dunce::canonicalize(path.join(&target).as_path()) {
                     Ok(p) => p,
                     Err(_) => {
-                        return Err(ShellError::labeled_error(
+                        let error = Err(ShellError::labeled_error(
                             "Can not change to directory",
                             "directory not found",
                             v.span().clone(),
                         ));
+
+                        if let Some(t) = target.to_str() {
+                            if t == "-" {
+                                match dunce::canonicalize(PathBuf::from(self.last_path.clone()).as_path()) {
+                                    Ok(p) => p,
+                                    Err(_) => {
+                                        return error;
+                                    }
+                                }
+                            } else {
+                                return error;
+                            }
+                        } else {
+                            return error;
+                        }
                     }
                 }
             }
@@ -959,6 +979,7 @@ impl Shell for FilesystemShell {
                 pathbuf
             }
         };
+        self.last_path = self.path.clone();
         self.path = path.to_string_lossy().to_string();
     }
 
diff --git a/tests/command_cd_tests.rs b/tests/command_cd_tests.rs
index 216bcc8c80..7c1a9f6b85 100644
--- a/tests/command_cd_tests.rs
+++ b/tests/command_cd_tests.rs
@@ -1,5 +1,7 @@
 mod helpers;
 
+use helpers::Playground;
+
 #[test]
 fn cd_directory_not_found() {
     let actual = nu_error!(
@@ -10,3 +12,35 @@ fn cd_directory_not_found() {
     assert!(actual.contains("dir_that_does_not_exist"));
     assert!(actual.contains("directory not found"));
 }
+
+#[test]
+fn cd_back() {
+    Playground::setup("cd_test_back", |dirs, sandbox| {
+        sandbox
+            .mkdir("andres")
+            .mkdir("odin");
+
+        let odin = dirs.test().join("odin");
+        let andres = dirs.test().join("andres");
+
+        nu!(
+            cwd: dirs.test(),
+            r#"
+                cd odin
+                mkdir a
+                cd ../andres
+                mkdir b
+                cd -
+                mkdir c
+                mkdir -
+                cd -
+                mkdir d
+            "#
+        );
+
+        assert!(odin.join("a").exists());
+        assert!(andres.join("b").exists());
+        assert!(odin.join("c").exists());
+        assert!(odin.join("-").join("d").exists());
+    })
+}