Add the ability to clone a display while changing the display plugin

I would really like to have this feature but it has to be clear for the user that the options which are special for this display (which are not that easy to detect) might be removed.

I agree this is a great idea. Perhaps a nice way of implementing this would be to offer a 'Clone as...' option, so the user's provided with a duplicate in the new display style which they can preview before saving.

Thanks for the patch. I patched the version 7.x-3.3 - I cloned the page as a block. Clone title and filter settings are not working. More precisely cloned default.

Let's implement that for Drupal 8.

Got it working for overridden values as well.

Nice, that's the main issue I found. I'll test this in the morning!

+++ b/core/modules/views/views_ui/lib/Drupal/views_ui/ViewEditFormController.phpundefined
@@ -766,6 +781,31 @@ public function submitDisplayAdd($form, &$form_state) {
+    $displays[$new_display_id]['id'] = $new_display_id;

We should probably unset (maybe?) or set the display_title to something too? As at the moment, wont this just inherit whatever the display being cloned from has? So if you cloned 'Page 7' your clone display title would also be 'Page 7'.

Yeah you are right, what about something like that?

Rewrote that cloning part to better work as expected and added a test.

+++ b/core/modules/views/views_ui/lib/Drupal/views_ui/ViewEditFormController.phpundefined
@@ -788,14 +788,17 @@ public function submitCloneDisplayAsType($form, &$form_state) {
+    $display_clone = $displays[$display_id];
+    unset($display_clone['display_title']);
 
-    // Copy the display options and plugin but leave the title left.
-    $displays[$new_display_id]['display_options'] = $displays[$display_id]['display_options'];
-    $displays[$new_display_id]['display_plugin'] = $displays[$display_id]['display_plugin'];
+    $displays[$new_display_id] += $display_clone;

That's a much cleaner way to merge the options, I was going to suggest something along those lines :) Like that.

This patch is looking good now. It is working as expected with the overridden options, as well as the quibble with the title.

I wont RTBC just yet, we should get a couple more people to test first.

The tests were assertingEqual for the title, but asserting on the display plugin object and not the display_title, also the change in #15 for the merging (+=) doesn't do a deep merge, so I've added NestedArray::mergeDeep instead, we can use this (which I'm ok with) or switch back to the previous method of doing this.

Also, probably out of scope for here, but I think the regular submitDisplayDuplicate method doesn't handle the title properly, if you have a page and you clone the title will still be 'Page'.

Oops! a real patch would be good. Thanks tim.

This change looks fine, so do you agree this is RTBC?

I am happy with this now, but I did the last fix. So maybe Tim should do the honours?!

uggggggh thanks for opening these eyes ... I swear this worked in the first versions of the patch!

#24: drupal-1401778-24.patch queued for re-testing.

We need to get() that stuff instead.

#28: 1401778-28.patch queued for re-testing.

Thanks for bringing this back to the table!
Back to RTBC once it's green.

Looks good. Committed/pushed to 8.x

Is that possible to backport to D7?

Was this ever ported?

subscribing for d7 port

Brilliant, thanks Alex.
Patch in #41 seems to be working fine with latest 7.x-3.20+0-dev.

Brilliant #41 works perfect! Thanks

This patch is the time-saver of the year! Works brilliantly against the latest dev, views just got even better. Thanks everyone!

Nice work everyone.

Has anyone tested to see if there are problems cloning a display and carrying along settings which are not appropriate for the new display type? For example, if you clone a page and make it a block, do errors show up related to the original page display's options? Are the old settings exported with the new display?

For my part, I've been cloning at least a dozen blocks to panels content panes and not a single error. Neither did settings get lost that are shared between source and clone (such as table style config like sorting options, css row classes, etc). I've also cloned a page to a views data export display and no problems at all.

Also aplied the patch against latest stable version, and everything works fine too.

This is indeed really great work, and to much delight.

Patch #41 works for me tested using Drupal 7.70 with patch applied to Views 7.x-3.24
Cloning a page (with menu parameters) to a block triggered no errors so far, all settings where cloned perfectly (except unrelevant like menu) and both page and block run OK.
Thanks to all for your efforts.

#41 worked great. Setting as RTBC, since others have said it works perfectly as well. Thanks for everyone's work on this!

Applying the patch from #41 gives me the error:

At line:1 char:7
+ patch < views-clone-display-as-1401778-41-D7.patch
+       ~
The '<' operator is reserved for future use.
    + CategoryInfo          : ParserError: (:) [], ParentContainsErrorRecordException
    + FullyQualifiedErrorId : RedirectionNotSupported

Committed. Thank you all!