[FIX] web: improve automatic creation of new lines in x2many in forms

This commit fixes a few issues with the previous implementation of the
automatic addition of new lines in x2many inside forms

1. Before this commit, when there is a change of mode in a formview
`edit` -> `readonly` -> `edit`, there may be some cases that
mistakenly and automatically opens a modal.

This case occurs in a form view with a x2many field whose 1st inner
focusable element opens a modal (e.g. "Add an item").

In `edit` mode:
	1. Open this modal from the x2many
	2. Close the modal
	3. Change mode to `readonly`
	4. Change mode to `edit`
> the same modal is automatically open.

This is due to the tracking of the last activated field that persists
after a change of mode. Since the last activated field in the 1st
`edit` is the x2many, it is granted the focus at the beginning of the
2nd `edit`, which automatically opens the modal.

This commit fixes the issue by resetting the tracking of the last
activated field when there is a change of mode. As a result, at the
beginning of the 2nd `edit`, the focus should always be on the 1st
field.

2. Before this commit, if the focus was moved out of the form (to a modal
for instance) then back, the form would re-activate the last field, which
is the x2many and would re-add a new line. This behavior is not correct
and now going back from a modal to a form does not add a new line.

Co-authored-by: Alexandre Kühn <aku@odoo.com>

1 files changed, 10 insertions, 4 deletions

diff --git a/addons/web/static/src/js/views/basic/basic_renderer.js b/addons/web/static/src/js/views/basic/basic_renderer.js
index 197892f3361..33267283a15 100644
--- a/addons/web/static/src/js/views/basic/basic_renderer.js
+++ b/addons/web/static/src/js/views/basic/basic_renderer.js
@@ -168,9 +168,10 @@ var BasicRenderer = AbstractRenderer.extend({
      * @private
      * @param {Object} record
      * @param {integer} currentIndex
-     * @param {Object} [options]
+     * @param {Object} [options={}]
      * @param {integer} [options.inc=1] - the increment to use when searching for the
      *   "next" possible one
+     * @param {boolean} [options.noAutomaticCreate=false]
      * @param {boolean} [options.wrap=false] if true, when we arrive at the end of the
      *   list of widget, we wrap around and try to activate widgets starting at
      *   the beginning. Otherwise, we just stop trying and return -1
@@ -184,7 +185,11 @@ var BasicRenderer = AbstractRenderer.extend({
 
         var recordWidgets = this.allFieldWidgets[record.id] || [];
         for (var i = 0 ; i < recordWidgets.length ; i++) {
-            var activated = recordWidgets[currentIndex].activate({event: options.event});
+            var activated = recordWidgets[currentIndex].activate(
+                {
+                    event: options.event,
+                    noAutomaticCreate: options.noAutomaticCreate || false
+                });
             if (activated) {
                 return currentIndex;
             }
@@ -213,11 +218,12 @@ var BasicRenderer = AbstractRenderer.extend({
      * @private
      * @param {Object} record
      * @param {integer} currentIndex
+     * @param {Object|undefined} options
      * @return {integer}
      */
-    _activateNextFieldWidget: function (record, currentIndex) {
+    _activateNextFieldWidget: function (record, currentIndex, options) {
         currentIndex = (currentIndex + 1) % (this.allFieldWidgets[record.id] || []).length;
-        return this._activateFieldWidget(record, currentIndex, {inc: 1});
+        return this._activateFieldWidget(record, currentIndex, _.extend({inc: 1}, options));
     },
     /**
      * This is a wrapper of the {@see _activateFieldWidget} function to select