patch 8.2.0909: cannot go back to the previous local directory

Problem:    Cannot go back to the previous local directory.
Solution:   Add "tcd -" and "lcd -". (Yegappan Lakshmanan, closes #4362)

runtime/doc/editing.txt

@@ -1326,6 +1326,10 @@ present in 'cpoptions' and "!" is not used in the command.
 							*:tch* *:tchdir*
 :tch[dir][!]		Same as |:tcd|.
 
+							*:tcd-*
+:tcd[!] -		Change to the previous current directory, before the
+			last ":tcd {path}" command.
+
 							*:lc* *:lcd*
 :lc[d][!] {path}	Like |:cd|, but only set the current directory when
 			the cursor is in the current window.  The current
@@ -1335,6 +1339,10 @@ present in 'cpoptions' and "!" is not used in the command.
 							*:lch* *:lchdir*
 :lch[dir][!]		Same as |:lcd|.
 
+							*:lcd-*
+:lcd[!] -		Change to the previous current directory, before the
+			last ":lcd {path}" command.
+
 							*:pw* *:pwd* *E187*
 :pw[d]			Print the current directory name.
 			Also see |getcwd()|.

src/ex_docmd.c

@@ -6581,6 +6581,19 @@ free_cd_dir(void)
 }
 #endif
 
+/*
+ * Get the previous directory for the given chdir scope.
+ */
+    static char_u *
+get_prevdir(cdscope_T scope)
+{
+    if (scope == CDSCOPE_WINDOW)
+	return curwin->w_prevdir;
+    else if (scope == CDSCOPE_TABPAGE)
+	return curtab->tp_prevdir;
+    return prev_dir;
+}
+
 /*
  * Deal with the side effects of changing the current directory.
  * When 'scope' is CDSCOPE_TABPAGE then this was after an ":tcd" command.
@@ -6595,10 +6608,13 @@ post_chdir(cdscope_T scope)
     VIM_CLEAR(curwin->w_localdir);
     if (scope != CDSCOPE_GLOBAL)
     {
-	// If still in global directory, need to remember current
-	// directory as global directory.
-	if (globaldir == NULL && prev_dir != NULL)
-	    globaldir = vim_strsave(prev_dir);
+	char_u	*pdir = get_prevdir(scope);
+
+	// If still in the global directory, need to remember current
+	// directory as the global directory.
+	if (globaldir == NULL && pdir != NULL)
+	    globaldir = vim_strsave(pdir);
+
 	// Remember this local directory for the window.
 	if (mch_dirname(NameBuff, MAXPATHL) == OK)
 	{
@@ -6610,8 +6626,7 @@ post_chdir(cdscope_T scope)
     }
     else
     {
-	// We are now in the global directory, no need to remember its
-	// name.
+	// We are now in the global directory, no need to remember its name.
 	VIM_CLEAR(globaldir);
     }
 
@@ -6633,6 +6648,7 @@ changedir_func(
 	cdscope_T	scope)
 {
     char_u	*tofree;
+    char_u	*pdir = NULL;
     int		dir_differs;
     int		retval = FALSE;
 
@@ -6648,20 +6664,29 @@ changedir_func(
     // ":cd -": Change to previous directory
     if (STRCMP(new_dir, "-") == 0)
     {
-	if (prev_dir == NULL)
+	pdir = get_prevdir(scope);
+	if (pdir == NULL)
 	{
 	    emsg(_("E186: No previous directory"));
 	    return FALSE;
 	}
-	new_dir = prev_dir;
+	new_dir = pdir;
     }
 
+    // Free the previous directory
+    tofree = get_prevdir(scope);
+
     // Save current directory for next ":cd -"
-    tofree = prev_dir;
     if (mch_dirname(NameBuff, MAXPATHL) == OK)
-	prev_dir = vim_strsave(NameBuff);
+	pdir = vim_strsave(NameBuff);
     else
-	prev_dir = NULL;
+	pdir = NULL;
+    if (scope == CDSCOPE_WINDOW)
+	curwin->w_prevdir = pdir;
+    else if (scope == CDSCOPE_TABPAGE)
+	curtab->tp_prevdir = pdir;
+    else
+	prev_dir = pdir;
 
 #if defined(UNIX) || defined(VMS)
     // for UNIX ":cd" means: go to home directory
@@ -6682,8 +6707,8 @@ changedir_func(
 	new_dir = NameBuff;
     }
 #endif
-    dir_differs = new_dir == NULL || prev_dir == NULL
-	|| pathcmp((char *)prev_dir, (char *)new_dir, -1) != 0;
+    dir_differs = new_dir == NULL || pdir == NULL
+	|| pathcmp((char *)pdir, (char *)new_dir, -1) != 0;
     if (new_dir == NULL || (dir_differs && vim_chdir(new_dir)))
 	emsg(_(e_failed));
     else

src/filepath.c

@@ -726,6 +726,7 @@ f_chdir(typval_T *argvars, typval_T *rettv)
 
     if (argvars[0].v_type != VAR_STRING)
 	// Returning an empty string means it failed.
+	// No error message, for historic reasons.
 	return;
 
     // Return the current directory

src/structs.h

@@ -2994,6 +2994,8 @@ struct tabpage_S
 
     char_u	    *tp_localdir;	// absolute path of local directory or
 					// NULL
+    char_u	    *tp_prevdir;	// previous directory
+
 #ifdef FEAT_DIFF
     diff_T	    *tp_first_diff;
     buf_T	    *(tp_diffbuf[DB_COUNT]);
@@ -3397,6 +3399,7 @@ struct window_S
 
     char_u	*w_localdir;	    // absolute path of local directory or
 				    // NULL
+    char_u	*w_prevdir;	    // previous directory
 #ifdef FEAT_MENU
     vimmenu_T	*w_winbar;	    // The root of the WinBar menu hierarchy.
     winbar_item_T *w_winbar_items;  // list of items in the WinBar

src/testdir/test_cd.vim

@@ -129,6 +129,69 @@ func Test_chdir_func()
   call delete('Xdir', 'rf')
 endfunc
 
+" Test for changing to the previous directory '-'
+func Test_prev_dir()
+  let topdir = getcwd()
+  call mkdir('Xdir/a/b/c', 'p')
+
+  " Create a few tabpages and windows with different directories
+  new | only
+  tabnew | new
+  tabnew
+  tabfirst
+  cd Xdir
+  tabnext | wincmd t
+  tcd a
+  wincmd w
+  lcd b
+  tabnext
+  tcd a/b/c
+
+  " Change to the previous directory twice in all the windows.
+  tabfirst
+  cd - | cd -
+  tabnext | wincmd t
+  tcd - | tcd -
+  wincmd w
+  lcd - | lcd -
+  tabnext
+  tcd - | tcd -
+
+  " Check the directory of all the windows
+  tabfirst
+  call assert_equal('Xdir', fnamemodify(getcwd(), ':t'))
+  tabnext | wincmd t
+  call assert_equal('a', fnamemodify(getcwd(), ':t'))
+  wincmd w
+  call assert_equal('b', fnamemodify(getcwd(), ':t'))
+  tabnext
+  call assert_equal('c', fnamemodify(getcwd(), ':t'))
+
+  " Change to the previous directory using chdir()
+  tabfirst
+  call chdir("-") | call chdir("-")
+  tabnext | wincmd t
+  call chdir("-") | call chdir("-")
+  wincmd w
+  call chdir("-") | call chdir("-")
+  tabnext
+  call chdir("-") | call chdir("-")
+
+  " Check the directory of all the windows
+  tabfirst
+  call assert_equal('Xdir', fnamemodify(getcwd(), ':t'))
+  tabnext | wincmd t
+  call assert_equal('a', fnamemodify(getcwd(), ':t'))
+  wincmd w
+  call assert_equal('b', fnamemodify(getcwd(), ':t'))
+  tabnext
+  call assert_equal('c', fnamemodify(getcwd(), ':t'))
+
+  only | tabonly
+  call chdir(topdir)
+  call delete('Xdir', 'rf')
+endfunc
+
 func Test_cd_completion()
   call mkdir('XComplDir1', 'p')
   call mkdir('XComplDir2', 'p')

src/version.c

@@ -746,6 +746,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    909,
 /**/
     908,
 /**/

src/window.c

@@ -3809,6 +3809,7 @@ free_tabpage(tabpage_T *tp)
 #endif
 
     vim_free(tp->tp_localdir);
+    vim_free(tp->tp_prevdir);
 
 #ifdef FEAT_PYTHON
     python_tabpage_free(tp);
@@ -4974,6 +4975,7 @@ win_free(
 	vim_free(wp->w_tagstack[i].user_data);
     }
     vim_free(wp->w_localdir);
+    vim_free(wp->w_prevdir);
 
     // Remove the window from the b_wininfo lists, it may happen that the
     // freed memory is re-used for another window.