vim-patch:8.0.1459: cannot handle change of directory

Problem:    Cannot handle change of directory.
Solution:   Add the DirChanged autocommand event. (Andy Massimino,
            closes vim/vim#888)  Avoid changing directory for 'autochdir' too often.
https://github.com/vim/vim/commit/b7407d3fc9496f9048fb65ab17b5ba3444965c0e

Only add "auto" pattern. "window" and "global" are already implemented.
Skip `Test_dirchanged_auto` using `CheckFunction test_autochdir`.
Part of PR #15952. More information can be found there.

N/A patches for version.c:

vim-patch:8.0.1460: missing file in patch

Problem:    Missing file in patch.
Solution:   Add changes to missing file.
https://github.com/vim/vim/commit/b5cb65ba2bcc6bbc6d2798a2dea18b95f0b38f5e

vim-patch:8.0.1461: missing another file in patch

Problem:    Missing another file in patch.
Solution:   Add changes to missing file.
https://github.com/vim/vim/commit/15833239a4131279935a4bd574b74fe3a2b0f49f

1 files changed, 18 insertions, 6 deletions

diff --git a/src/nvim/file_search.c b/src/nvim/file_search.c
index 5458d8acf2..e7c4785beb 100644
--- a/src/nvim/file_search.c
+++ b/src/nvim/file_search.c
@@ -1590,7 +1590,7 @@ theend:
   return file_name;
 }
 
-void do_autocmd_dirchanged(char *new_dir, CdScope scope, bool changed_window)
+void do_autocmd_dirchanged(char *new_dir, CdScope scope, CdCause cause)
 {
   static bool recursive = false;
 
@@ -1621,10 +1621,22 @@ void do_autocmd_dirchanged(char *new_dir, CdScope scope, bool changed_window)
   }
 
   tv_dict_add_str(dict, S_LEN("scope"), buf);  // -V614
-  tv_dict_add_str(dict, S_LEN("cwd"),   new_dir);
-  tv_dict_add_bool(dict, S_LEN("changed_window"), changed_window);
+  tv_dict_add_str(dict, S_LEN("cwd"), new_dir);
+  tv_dict_add_bool(dict, S_LEN("changed_window"), cause == kCdCauseWindow);
   tv_dict_set_keys_readonly(dict);
 
+  switch (cause) {
+  case kCdCauseManual:
+  case kCdCauseWindow:
+    break;
+  case kCdCauseAuto:
+    snprintf(buf, sizeof(buf), "auto");
+    break;
+  case kCdCauseOther:
+    // Should never happen.
+    abort();
+  }
+
   apply_autocmds(EVENT_DIRCHANGED, (char_u *)buf, (char_u *)new_dir, false,
                  curbuf);
 
@@ -1636,7 +1648,7 @@ void do_autocmd_dirchanged(char *new_dir, CdScope scope, bool changed_window)
 /// Change to a file's directory.
 /// Caller must call shorten_fnames()!
 /// @return OK or FAIL
-int vim_chdirfile(char_u *fname)
+int vim_chdirfile(char_u *fname, CdCause cause)
 {
   char dir[MAXPATHL];
 
@@ -1654,8 +1666,8 @@ int vim_chdirfile(char_u *fname)
 #ifdef BACKSLASH_IN_FILENAME
   slash_adjust((char_u *)dir);
 #endif
-  if (!strequal(dir, (char *)NameBuff)) {
-    do_autocmd_dirchanged(dir, kCdScopeWindow, false);
+  if (cause != kCdCauseOther && !strequal(dir, (char *)NameBuff)) {
+    do_autocmd_dirchanged(dir, kCdScopeWindow, cause);
   }
 
   return OK;