patch 8.2.4343: when reloading not all properties are detected

Problem:    When reloading not all properties are detected.
Solution:   Add the "edit" value to v:fcs_choice. (Rob Pilling, closes #9579)

runtime/doc/editing.txt

@@ -1650,6 +1650,11 @@ If you don't get warned often enough you can use the following command.
 			if it exists now.
 			Once a file has been checked the timestamp is reset,
 			you will not be warned again.
+			Syntax highlighting, marks, diff status,
+			'fileencoding', 'fileformat' and 'binary' options
+			are not changed.  See |v:fcs_choice| to reload these
+			too (for example, if a code formatting tools has
+			changed the file).
 
 :[N]checkt[ime] {filename}
 :[N]checkt[ime] [N]

runtime/doc/eval.txt

@@ -2070,6 +2070,11 @@ v:fcs_choice	What should happen after a |FileChangedShell| event was
 		do with the affected buffer:
 			reload		Reload the buffer (does not work if
 					the file was deleted).
+			edit		Reload the buffer and detect the
+					values for options such as
+					'fileformat', 'fileencoding', 'binary'
+					(does not work if the file was
+					deleted).
 			ask		Ask the user what to do, as if there
 					was no autocommand.  Except that when
 					only the timestamp changed nothing

src/fileio.c

@@ -2697,7 +2697,7 @@ readfile_linenr(
 }
 
 /*
- * Fill "*eap" to force the 'fileencoding', 'fileformat' and 'binary to be
+ * Fill "*eap" to force the 'fileencoding', 'fileformat' and 'binary' to be
  * equal to the buffer "buf".  Used for calling readfile().
  * Returns OK or FAIL.
  */
@@ -4041,7 +4041,11 @@ buf_check_timestamp(
     char	*mesg = NULL;
     char	*mesg2 = "";
     int		helpmesg = FALSE;
-    int		reload = FALSE;
+    enum {
+	RELOAD_NONE,
+	RELOAD_NORMAL,
+	RELOAD_DETECT
+    }		reload = RELOAD_NONE;
     char	*reason;
 #if defined(FEAT_CON_DIALOG) || defined(FEAT_GUI_DIALOG)
     int		can_reload = FALSE;
@@ -4117,7 +4121,7 @@ buf_check_timestamp(
 	 */
 	else if ((buf->b_p_ar >= 0 ? buf->b_p_ar : p_ar)
 				       && !bufIsChanged(buf) && stat_res >= 0)
-	    reload = TRUE;
+	    reload = RELOAD_NORMAL;
 	else
 	{
 	    if (stat_res < 0)
@@ -4158,7 +4162,9 @@ buf_check_timestamp(
 #ifdef FEAT_EVAL
 		s = get_vim_var_str(VV_FCS_CHOICE);
 		if (STRCMP(s, "reload") == 0 && *reason != 'd')
-		    reload = TRUE;
+		    reload = RELOAD_NORMAL;
+		else if (STRCMP(s, "edit") == 0)
+		    reload = RELOAD_DETECT;
 		else if (STRCMP(s, "ask") == 0)
 		    n = FALSE;
 		else
@@ -4239,10 +4245,18 @@ buf_check_timestamp(
 		    STRCAT(tbuf, "\n");
 		    STRCAT(tbuf, mesg2);
 		}
-		if (do_dialog(VIM_WARNING, (char_u *)_("Warning"),
+		switch (do_dialog(VIM_WARNING, (char_u *)_("Warning"),
-			    (char_u *)tbuf,
+			(char_u *)tbuf,
-			  (char_u *)_("&OK\n&Load File"), 1, NULL, TRUE) == 2)
+			(char_u *)_("&OK\n&Load File\nLoad File &and Options"),
-		    reload = TRUE;
+			1, NULL, TRUE))
+		{
+		    case 2:
+			reload = RELOAD_NORMAL;
+			break;
+		    case 3:
+			reload = RELOAD_DETECT;
+			break;
+		}
 	    }
 	    else
 #endif
@@ -4287,10 +4301,10 @@ buf_check_timestamp(
 	}
     }
 
-    if (reload)
+    if (reload != RELOAD_NONE)
     {
 	// Reload the buffer.
-	buf_reload(buf, orig_mode);
+	buf_reload(buf, orig_mode, reload == RELOAD_DETECT);
 #ifdef FEAT_PERSISTENT_UNDO
 	if (buf->b_p_udf && buf->b_ffname != NULL)
 	{
@@ -4326,7 +4340,7 @@ buf_check_timestamp(
  * buf->b_orig_mode may have been reset already.
  */
     void
-buf_reload(buf_T *buf, int orig_mode)
+buf_reload(buf_T *buf, int orig_mode, int reload_options)
 {
     exarg_T	ea;
     pos_T	old_cursor;
@@ -4337,14 +4351,20 @@ buf_reload(buf_T *buf, int orig_mode)
     int		saved = OK;
     aco_save_T	aco;
     int		flags = READ_NEW;
+    int		prepped = OK;
 
     // set curwin/curbuf for "buf" and save some things
     aucmd_prepbuf(&aco, buf);
 
-    // We only want to read the text from the file, not reset the syntax
+    // Unless reload_options is set, we only want to read the text from the
-    // highlighting, clear marks, diff status, etc.  Force the fileformat
+    // file, not reset the syntax highlighting, clear marks, diff status, etc.
-    // and encoding to be the same.
+    // Force the fileformat and encoding to be the same.
-    if (prep_exarg(&ea, buf) == OK)
+    if (reload_options)
+	memset(&ea, 0, sizeof(ea));
+    else
+	prepped = prep_exarg(&ea, buf);
+
+    if (prepped == OK)
     {
 	old_cursor = curwin->w_cursor;
 	old_topline = curwin->w_topline;

src/message.c

@@ -3752,6 +3752,8 @@ msg_advance(int col)
  * Other buttons- use your imagination!
  * A '&' in a button name becomes a shortcut, so each '&' should be before a
  * different letter.
+ *
+ * Returns 0 if cancelled, otherwise the nth button (1-indexed).
  */
     int
 do_dialog(

src/proto/fileio.pro

@@ -28,7 +28,7 @@ int vim_fgets(char_u *buf, int size, FILE *fp);
 int vim_rename(char_u *from, char_u *to);
 int check_timestamps(int focus);
 int buf_check_timestamp(buf_T *buf, int focus);
-void buf_reload(buf_T *buf, int orig_mode);
+void buf_reload(buf_T *buf, int orig_mode, int reload_options);
 void buf_store_time(buf_T *buf, stat_T *st, char_u *fname);
 void write_lnum_adjust(linenr_T offset);
 int readdir_core(garray_T *gap, char_u *path, int withattr, void *context, int (*checkitem)(void *context, void *item), int sort);

src/spellfile.c

@@ -6336,7 +6336,7 @@ spell_add_word(
 
 	// If the .add file is edited somewhere, reload it.
 	if (buf != NULL)
-	    buf_reload(buf, buf->b_orig_mode);
+	    buf_reload(buf, buf->b_orig_mode, FALSE);
 
 	redraw_all_later(SOME_VALID);
     }

src/testdir/test_filechanged.vim

@@ -91,6 +91,100 @@ func Test_FileChangedShell_reload()
   call delete('Xchanged_r')
 endfunc
 
+func Test_FileChangedShell_edit()
+  CheckUnix
+
+  new Xchanged_r
+  call setline(1, 'reload this')
+  set fileformat=unix
+  write
+
+  " File format changed, reload (content only, no 'ff' etc)
+  augroup testreload
+    au!
+    au FileChangedShell Xchanged_r let g:reason = v:fcs_reason | let v:fcs_choice = 'reload'
+  augroup END
+  call assert_equal(&fileformat, 'unix')
+  call writefile(["line1\r", "line2\r"], 'Xchanged_r')
+  let g:reason = ''
+  checktime
+  call assert_equal('changed', g:reason)
+  call assert_equal(&fileformat, 'unix')
+  call assert_equal("line1\r", getline(1))
+  call assert_equal("line2\r", getline(2))
+  %s/\r
+  write
+
+  " File format changed, reload with 'ff', etc
+  augroup testreload
+    au!
+    au FileChangedShell Xchanged_r let g:reason = v:fcs_reason | let v:fcs_choice = 'edit'
+  augroup END
+  call assert_equal(&fileformat, 'unix')
+  call writefile(["line1\r", "line2\r"], 'Xchanged_r')
+  let g:reason = ''
+  checktime
+  call assert_equal('changed', g:reason)
+  call assert_equal(&fileformat, 'dos')
+  call assert_equal('line1', getline(1))
+  call assert_equal('line2', getline(2))
+  set fileformat=unix
+  write
+
+  au! testreload
+  bwipe!
+  call delete(undofile('Xchanged_r'))
+  call delete('Xchanged_r')
+endfunc
+
+func Test_FileChangedShell_edit_dialog()
+  CheckNotGui
+
+  new Xchanged_r
+  call setline(1, 'reload this')
+  set fileformat=unix
+  write
+
+  " File format changed, reload (content only) via prompt
+  augroup testreload
+    au!
+    au FileChangedShell Xchanged_r let g:reason = v:fcs_reason | let v:fcs_choice = 'ask'
+  augroup END
+  call assert_equal(&fileformat, 'unix')
+  call writefile(["line1\r", "line2\r"], 'Xchanged_r')
+  let g:reason = ''
+  call feedkeys('L', 'L') " load file content only
+  checktime
+  call assert_equal('changed', g:reason)
+  call assert_equal(&fileformat, 'unix')
+  call assert_equal("line1\r", getline(1))
+  call assert_equal("line2\r", getline(2))
+  %s/\r
+  write
+
+  " File format changed, reload (file and options) via prompt
+  augroup testreload
+    au!
+    au FileChangedShell Xchanged_r let g:reason = v:fcs_reason | let v:fcs_choice = 'ask'
+  augroup END
+  call assert_equal(&fileformat, 'unix')
+  call writefile(["line1\r", "line2\r"], 'Xchanged_r')
+  let g:reason = ''
+  call feedkeys('a', 'L') " load file content and options
+  checktime
+  call assert_equal('changed', g:reason)
+  call assert_equal(&fileformat, 'dos')
+  call assert_equal("line1", getline(1))
+  call assert_equal("line2", getline(2))
+  set fileformat=unix
+  write
+
+  au! testreload
+  bwipe!
+  call delete(undofile('Xchanged_r'))
+  call delete('Xchanged_r')
+endfunc
+
 func Test_file_changed_dialog()
   CheckUnix
   CheckNotGui

src/version.c

@@ -746,6 +746,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    4343,
 /**/
     4342,
 /**/