patch 8.1.2278: using "cd" with "exe" may fail

Problem:    Using "cd" with "exe" may fail.
Solution:   Use chdir() instead.
diff --git a/src/testdir/test_autochdir.vim b/src/testdir/test_autochdir.vim
index 98d1af7..1473854 100644
--- a/src/testdir/test_autochdir.vim
+++ b/src/testdir/test_autochdir.vim
@@ -21,6 +21,6 @@
   bwipe!
   au! DirChanged
   set noacd
-  exe 'cd ' . cwd
+  call chdir(cwd)
   call delete('samples/Xtest')
 endfunc
diff --git a/src/testdir/test_autocmd.vim b/src/testdir/test_autocmd.vim
index 1e53fe4..13febb0 100644
--- a/src/testdir/test_autocmd.vim
+++ b/src/testdir/test_autocmd.vim
@@ -1731,7 +1731,7 @@
 endfunc
 
 function s:After_test_dirchanged()
-  exe 'cd' s:dir_this
+  call chdir(s:dir_this)
   call delete(s:dir_foo, 'd')
   call delete(s:dir_bar, 'd')
   augroup test_dirchanged
@@ -1743,11 +1743,11 @@
   call s:Before_test_dirchanged()
   autocmd test_dirchanged DirChanged global call add(s:li, "cd:")
   autocmd test_dirchanged DirChanged global call add(s:li, expand("<afile>"))
-  exe 'cd' s:dir_foo
+  call chdir(s:dir_foo)
   call assert_equal(["cd:", s:dir_foo], s:li)
-  exe 'cd' s:dir_foo
+  call chdir(s:dir_foo)
   call assert_equal(["cd:", s:dir_foo], s:li)
-  exe 'lcd' s:dir_bar
+  exe 'lcd ' .. fnameescape(s:dir_bar)
   call assert_equal(["cd:", s:dir_foo], s:li)
   call s:After_test_dirchanged()
 endfunc
@@ -1756,11 +1756,11 @@
   call s:Before_test_dirchanged()
   autocmd test_dirchanged DirChanged window call add(s:li, "lcd:")
   autocmd test_dirchanged DirChanged window call add(s:li, expand("<afile>"))
-  exe 'cd' s:dir_foo
+  call chdir(s:dir_foo)
   call assert_equal([], s:li)
-  exe 'lcd' s:dir_bar
+  exe 'lcd ' .. fnameescape(s:dir_bar)
   call assert_equal(["lcd:", s:dir_bar], s:li)
-  exe 'lcd' s:dir_bar
+  exe 'lcd ' .. fnameescape(s:dir_bar)
   call assert_equal(["lcd:", s:dir_bar], s:li)
   call s:After_test_dirchanged()
 endfunc
@@ -1774,7 +1774,7 @@
   autocmd test_dirchanged DirChanged auto call add(s:li, "auto:")
   autocmd test_dirchanged DirChanged auto call add(s:li, expand("<afile>"))
   set acd
-  exe 'cd ..'
+  cd ..
   call assert_equal([], s:li)
   exe 'edit ' . s:dir_foo . '/Xfile'
   call assert_equal(s:dir_foo, getcwd())
diff --git a/src/testdir/test_cd.vim b/src/testdir/test_cd.vim
index c3589b4..bdb26cd 100644
--- a/src/testdir/test_cd.vim
+++ b/src/testdir/test_cd.vim
@@ -9,7 +9,7 @@
   let path = getcwd()
   cd ..
   call assert_notequal(path, getcwd())
-  exe 'cd ' . path
+  exe 'cd ' .. fnameescape(path)
   call assert_equal(path, getcwd())
 endfunc
 
@@ -20,7 +20,7 @@
     cd
     call assert_equal($HOME, getcwd())
     call assert_notequal(path, getcwd())
-    exe 'cd ' . path
+    exe 'cd ' .. fnameescape(path)
     call assert_equal(path, getcwd())
   else
     " Test that cd without argument echoes cwd on non-Unix systems.
@@ -58,7 +58,7 @@
 
   " :cd should succeed when buffer has been written.
   w!
-  exe 'cd ' . path
+  exe 'cd ' .. fnameescape(path)
   call assert_equal(path, getcwd())
 
   call delete('Xfoo')
@@ -103,6 +103,6 @@
   call assert_equal("", d)
 
   only | tabonly
-  exe 'cd ' . topdir
+  call chdir(topdir)
   call delete('Xdir', 'rf')
 endfunc
diff --git a/src/testdir/test_expand.vim b/src/testdir/test_expand.vim
index 53f753d..48dce25 100644
--- a/src/testdir/test_expand.vim
+++ b/src/testdir/test_expand.vim
@@ -35,7 +35,7 @@
   call assert_true(isdirectory('Xdir ~ dir'))
   cd Xdir\ ~\ dir
   call assert_true(getcwd() =~ 'Xdir \~ dir')
-  exe 'cd ' . fnameescape(dir)
+  call chdir(dir)
   call delete('Xdir ~ dir', 'd')
   call assert_false(isdirectory('Xdir ~ dir'))
 endfunc
diff --git a/src/testdir/test_find_complete.vim b/src/testdir/test_find_complete.vim
index a7bc135..679bf3c 100644
--- a/src/testdir/test_find_complete.vim
+++ b/src/testdir/test_find_complete.vim
@@ -36,7 +36,7 @@
   " We shouldn't find any file till this point
 
   call mkdir('in/path', 'p')
-  exe 'cd ' . cwd
+  call chdir(cwd)
   call writefile(['Holy Grail'], 'Xfind/file.txt')
   call writefile(['Jimmy Hoffa'], 'Xfind/in/file.txt')
   call writefile(['Another Holy Grail'], 'Xfind/in/stuff.txt')
@@ -133,12 +133,12 @@
   call assert_equal('Voyager 2', getline(1))
 
   " Check for correct handling of shorten_fname()'s behavior on windows
-  exec "cd " . cwd . "/Xfind/in"
+  call chdir(cwd .. "/Xfind/in")
   call feedkeys(":find file\t\n", "xt")
   call assert_equal('Jimmy Hoffa', getline(1))
 
   " Test for relative to current buffer 'path' item
-  exec "cd " . cwd . "/Xfind/"
+  call chdir(cwd . "/Xfind/")
   set path=./path
   " Open the file where Jimmy Hoffa is found
   e in/file.txt
@@ -157,7 +157,7 @@
   call assert_equal('Another Holy Grail', getline(1))
 
   enew | only
-  exe 'cd ' . cwd
+  call chdir(cwd)
   call delete('Xfind', 'rf')
   set path&
 endfunc
diff --git a/src/testdir/test_findfile.vim b/src/testdir/test_findfile.vim
index 5cda2ea..2e6f888 100644
--- a/src/testdir/test_findfile.vim
+++ b/src/testdir/test_findfile.vim
@@ -113,7 +113,7 @@
   call assert_match('.*/Xdir1/bar', findfile('bar', '**;', 2))
 
   bwipe!
-  exe 'cd  ' . save_dir
+  call chdir(save_dir)
   call CleanFiles()
   let &path = save_path
   let &shellslash = save_shellslash
@@ -170,7 +170,7 @@
   call assert_match('.*/Xdir1/Xdir2', finddir('Xdir2', '**;', 2))
   call assert_equal('Xdir3',          finddir('Xdir3', '**;', 1))
 
-  exe 'cd  ' . save_dir
+  call chdir(save_dir)
   call CleanFiles()
   let &path = save_path
   let &shellslash = save_shellslash
diff --git a/src/testdir/test_getcwd.vim b/src/testdir/test_getcwd.vim
index b1470d7..e87f693 100644
--- a/src/testdir/test_getcwd.vim
+++ b/src/testdir/test_getcwd.vim
@@ -46,7 +46,7 @@
 let g:cwd=getcwd()
 function TearDown()
   q
-  exec "cd " . g:cwd
+  call chdir(g:cwd)
   call delete("Xtopdir", "rf")
 endfunction
 
diff --git a/src/testdir/test_shortpathname.vim b/src/testdir/test_shortpathname.vim
index 6b3f85f..3c09b4c 100644
--- a/src/testdir/test_shortpathname.vim
+++ b/src/testdir/test_shortpathname.vim
@@ -51,7 +51,7 @@
   call TestIt(file2, ':p:8', resfile2)
   call TestIt(nofile2, ':p:8', resnofile2)
   call TestIt(nofile2, ':p:8:h', fnamemodify(resnofile2, ':h'))
-  exe 'cd ' . dir1
+  call chdir(dir1)
   call TestIt(file1, ':.:8', strpart(resfile1, strlen(resdir1)+1))
   call TestIt(nofile1, ':.:8', strpart(resnofile1, strlen(resdir1)+1))
   call TestIt(file2, ':.:8', strpart(resfile2, strlen(resdir1)+1))
@@ -68,7 +68,7 @@
   call delete(dir2, 'd')
   call delete(dir1, 'd')
 
-  exe "cd " . save_dir
+  call chdir(save_dir)
 endfunc
 
 func Test_ColonEight_MultiByte()
diff --git a/src/version.c b/src/version.c
index bb783f8..1ab0144 100644
--- a/src/version.c
+++ b/src/version.c
@@ -742,6 +742,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2278,
+/**/
     2277,
 /**/
     2276,