patch 8.1.0602: DirChanged is also triggered when directory didn't change

Problem:    DirChanged is also triggered when the directory didn't change.
            (Daniel Hahler)
Solution:   Compare the current with the new directory. (closes #3697)

src/ex_docmd.c

@@ -9126,8 +9126,9 @@ post_chdir(int local)
     void
 ex_cd(exarg_T *eap)
 {
-    char_u		*new_dir;
-    char_u		*tofree;
+    char_u	*new_dir;
+    char_u	*tofree;
+    int		dir_differs;
 
     new_dir = eap->arg;
 #if !defined(UNIX) && !defined(VMS)
@@ -9183,7 +9184,9 @@ ex_cd(exarg_T *eap)
 	    new_dir = NameBuff;
 	}
 #endif
-	if (new_dir == NULL || vim_chdir(new_dir))
+	dir_differs = new_dir == NULL || prev_dir == NULL
+					     || STRCMP(prev_dir, new_dir) != 0;
+	if (new_dir == NULL || (dir_differs && vim_chdir(new_dir)))
 	    EMSG(_(e_failed));
 	else
 	{
@@ -9195,9 +9198,11 @@ ex_cd(exarg_T *eap)
 	    /* Echo the new current directory if the command was typed. */
 	    if (KeyTyped || p_verbose >= 5)
 		ex_pwd(eap);
-	    apply_autocmds(EVENT_DIRCHANGED,
-		    is_local_chdir ? (char_u *)"window" : (char_u *)"global",
-		    new_dir, FALSE, curbuf);
+
+	    if (dir_differs)
+		apply_autocmds(EVENT_DIRCHANGED,
+		      is_local_chdir ? (char_u *)"window" : (char_u *)"global",
+		      new_dir, FALSE, curbuf);
 	}
 	vim_free(tofree);
     }

src/misc2.c

@@ -3390,17 +3390,29 @@ same_directory(char_u *f1, char_u *f2)
  * Return OK or FAIL.
  */
     int
-vim_chdirfile(char_u *fname, char *trigger_autocmd UNUSED)
+vim_chdirfile(char_u *fname, char *trigger_autocmd)
 {
-    char_u	dir[MAXPATHL];
+    char_u	old_dir[MAXPATHL];
+    char_u	new_dir[MAXPATHL];
     int		res;
 
-    vim_strncpy(dir, fname, MAXPATHL - 1);
-    *gettail_sep(dir) = NUL;
-    res = mch_chdir((char *)dir) == 0 ? OK : FAIL;
-    if (res == OK && trigger_autocmd != NULL)
-	apply_autocmds(EVENT_DIRCHANGED, (char_u *)trigger_autocmd,
-							   dir, FALSE, curbuf);
+    if (mch_dirname(old_dir, MAXPATHL) != OK)
+	*old_dir = NUL;
+
+    vim_strncpy(new_dir, fname, MAXPATHL - 1);
+    *gettail_sep(new_dir) = NUL;
+
+    if (STRCMP(old_dir, new_dir) == 0)
+	// nothing to do
+	res = OK;
+    else
+    {
+	res = mch_chdir((char *)new_dir) == 0 ? OK : FAIL;
+
+	if (res == OK && trigger_autocmd != NULL)
+	    apply_autocmds(EVENT_DIRCHANGED, (char_u *)trigger_autocmd,
+						       new_dir, FALSE, curbuf);
+    }
     return res;
 }
 #endif

src/testdir/test_autochdir.vim

@@ -8,11 +8,19 @@ func Test_set_filename()
   let cwd = getcwd()
   call test_autochdir()
   set acd
+
+  let s:li = []
+  autocmd DirChanged auto call add(s:li, "autocd")
+  autocmd DirChanged auto call add(s:li, expand("<afile>"))
+
   new
   w samples/Xtest
   call assert_equal("Xtest", expand('%'))
   call assert_equal("samples", substitute(getcwd(), '.*/\(\k*\)', '\1', ''))
+  call assert_equal(["autocd", getcwd()], s:li)
+
   bwipe!
+  au! DirChanged
   set noacd
   exe 'cd ' . cwd
   call delete('samples/Xtest')

src/testdir/test_autocmd.vim

@@ -1205,13 +1205,16 @@ function s:Before_test_dirchanged()
   augroup END
   let s:li = []
   let s:dir_this = getcwd()
-  let s:dir_other = s:dir_this . '/foo'
-  call mkdir(s:dir_other)
+  let s:dir_foo = s:dir_this . '/foo'
+  call mkdir(s:dir_foo)
+  let s:dir_bar = s:dir_this . '/bar'
+  call mkdir(s:dir_bar)
 endfunc
 
 function s:After_test_dirchanged()
   exe 'cd' s:dir_this
-  call delete(s:dir_other, 'd')
+  call delete(s:dir_foo, 'd')
+  call delete(s:dir_bar, 'd')
   augroup test_dirchanged
     autocmd!
   augroup END
@@ -1221,10 +1224,12 @@ function Test_dirchanged_global()
   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_other
-  call assert_equal(["cd:", s:dir_other], s:li)
-  exe 'lcd' s:dir_other
-  call assert_equal(["cd:", s:dir_other], s:li)
+  exe 'cd' s:dir_foo
+  call assert_equal(["cd:", s:dir_foo], s:li)
+  exe 'cd' s:dir_foo
+  call assert_equal(["cd:", s:dir_foo], s:li)
+  exe 'lcd' s:dir_bar
+  call assert_equal(["cd:", s:dir_foo], s:li)
   call s:After_test_dirchanged()
 endfunc
 
@@ -1232,10 +1237,12 @@ function Test_dirchanged_local()
   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_other
+  exe 'cd' s:dir_foo
   call assert_equal([], s:li)
-  exe 'lcd' s:dir_other
-  call assert_equal(["lcd:", s:dir_other], s:li)
+  exe 'lcd' s:dir_bar
+  call assert_equal(["lcd:", s:dir_bar], s:li)
+  exe 'lcd' s:dir_bar
+  call assert_equal(["lcd:", s:dir_bar], s:li)
   call s:After_test_dirchanged()
 endfunc
 
@@ -1250,9 +1257,9 @@ function Test_dirchanged_auto()
   set acd
   exe 'cd ..'
   call assert_equal([], s:li)
-  exe 'edit ' . s:dir_other . '/Xfile'
-  call assert_equal(s:dir_other, getcwd())
-  call assert_equal(["auto:", s:dir_other], s:li)
+  exe 'edit ' . s:dir_foo . '/Xfile'
+  call assert_equal(s:dir_foo, getcwd())
+  call assert_equal(["auto:", s:dir_foo], s:li)
   set noacd
   bwipe!
   call s:After_test_dirchanged()

src/version.c

@@ -799,6 +799,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    602,
 /**/
     601,
 /**/