patch 9.1.0507: hard to detect cursor movement in the command line

Problem:  hard to detect cursor movement in the command line
Solution: Add the CursorMovedC autocommand
          (Shougo Matsushita)

closes: #15040

Signed-off-by: Shougo Matsushita <Shougo.Matsu@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/autocmd.c b/src/autocmd.c
index 8380f8a..e60eac7 100644
--- a/src/autocmd.c
+++ b/src/autocmd.c
@@ -120,6 +120,7 @@
     KEYVALUE_ENTRY(EVENT_CURSORHOLD, "CursorHold"),
     KEYVALUE_ENTRY(EVENT_CURSORHOLDI, "CursorHoldI"),
     KEYVALUE_ENTRY(EVENT_CURSORMOVED, "CursorMoved"),
+    KEYVALUE_ENTRY(EVENT_CURSORMOVEDC, "CursorMovedC"),
     KEYVALUE_ENTRY(EVENT_CURSORMOVEDI, "CursorMovedI"),
     KEYVALUE_ENTRY(EVENT_DIFFUPDATED, "DiffUpdated"),
     KEYVALUE_ENTRY(EVENT_DIRCHANGED, "DirChanged"),
@@ -2250,6 +2251,7 @@
 		|| event == EVENT_CMDLINECHANGED
 		|| event == EVENT_CMDLINEENTER
 		|| event == EVENT_CMDLINELEAVE
+		|| event == EVENT_CURSORMOVEDC
 		|| event == EVENT_CMDWINENTER
 		|| event == EVENT_CMDWINLEAVE
 		|| event == EVENT_CMDUNDEFINED
diff --git a/src/ex_getln.c b/src/ex_getln.c
index 3444a0e..481b450 100644
--- a/src/ex_getln.c
+++ b/src/ex_getln.c
@@ -1586,6 +1586,7 @@
     int		res;
     int		save_msg_scroll = msg_scroll;
     int		save_State = State;	// remember State when called
+    int		save_cmdspos = ccline.cmdspos;
     int		some_key_typed = FALSE;	// one of the keys was typed
     // mouse drag and release events are ignored, unless they are
     // preceded with a mouse down event
@@ -2473,6 +2474,10 @@
  * (Sorry for the goto's, I know it is ugly).
  */
 cmdline_not_changed:
+	 // Trigger CursorMovedC autocommands.
+	 if (ccline.cmdspos != save_cmdspos)
+	    trigger_cmd_autocmd(cmdline_type, EVENT_CURSORMOVEDC);
+
 #ifdef FEAT_SEARCH_EXTRA
 	if (!is_state.incsearch_postponed)
 	    continue;
@@ -2484,8 +2489,8 @@
 	if (is_state.winid != curwin->w_id)
 	    init_incsearch_state(&is_state);
 #endif
+	// Trigger CmdlineChanged autocommands.
 	if (trigger_cmdlinechanged)
-	    // Trigger CmdlineChanged autocommands.
 	    trigger_cmd_autocmd(cmdline_type, EVENT_CMDLINECHANGED);
 
 #ifdef FEAT_SEARCH_EXTRA
@@ -4315,6 +4320,10 @@
 	new_cmdpos = 0;
     else
 	new_cmdpos = pos;
+
+    // Trigger CursorMovedC autocommands.
+    trigger_cmd_autocmd(get_cmdline_type(), EVENT_CURSORMOVEDC);
+
     return 0;
 }
 
diff --git a/src/testdir/test_autocmd.vim b/src/testdir/test_autocmd.vim
index c9f257a..faa0f97 100644
--- a/src/testdir/test_autocmd.vim
+++ b/src/testdir/test_autocmd.vim
@@ -2096,6 +2096,21 @@
   au! CmdlineEnter
   au! CmdlineLeave
   let &shellslash = save_shellslash
+
+  au! CursorMovedC : let g:pos = getcmdpos()
+  let g:pos = 0
+  call feedkeys(":hello\<Left>\<ESC>", 'xt')
+  call assert_equal(5, g:pos)
+  call feedkeys(":12345678\<C-R>=setcmdpos(3)\<CR>\<ESC>", 'xt')
+  call assert_equal(3, g:pos)
+  au! CursorMovedC
+
+  " CursorMovedC changes the cursor position.
+  au! CursorMovedC : let g:pos = getcmdpos() | call setcmdpos(getcmdpos()-1)
+  let g:pos = 0
+  call feedkeys(":hello\<Left>\<ESC>", 'xt')
+  call assert_equal(5, g:pos)
+  au! CursorMovedC
 endfunc
 
 " Test for BufWritePre autocommand that deletes or unloads the buffer.
diff --git a/src/version.c b/src/version.c
index 9d40d8f..da82b36 100644
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    507,
+/**/
     506,
 /**/
     505,
diff --git a/src/vim.h b/src/vim.h
index e703239..a80f844 100644
--- a/src/vim.h
+++ b/src/vim.h
@@ -1361,6 +1361,7 @@
     EVENT_CURSORHOLD,		// cursor in same position for a while
     EVENT_CURSORHOLDI,		// idem, in Insert mode
     EVENT_CURSORMOVED,		// cursor was moved
+    EVENT_CURSORMOVEDC,		// cursor was moved in Command line mode
     EVENT_CURSORMOVEDI,		// cursor was moved in Insert mode
     EVENT_DIFFUPDATED,		// after diffs were updated
     EVENT_DIRCHANGED,		// after user changed directory