[FIX] web: multi edition in editable listviews error handling

Fixed crashes/incorrect behaviours in multi edition in the list views.
The solution to these problems was mainly to refactor the function
used to save multiple records.

Before this commit:
- Cancelling the confirmation dialog in multi edition caused
the edited record to be editable but disabled
- Saving an empty field in multi edition triggered a JS error
- Static confirmation message ("saving 0 valid records")

After this commit:
- Ability to cancel confirmation
- Proper error display when trying to save empty fields
- Message consistent with the situation

2 files changed, 66 insertions, 34 deletions

diff --git a/addons/web/static/src/js/views/list/list_controller.js b/addons/web/static/src/js/views/list/list_controller.js
index 4edf5287ac2..65e2ed7f5a0 100644
--- a/addons/web/static/src/js/views/list/list_controller.js
+++ b/addons/web/static/src/js/views/list/list_controller.js
@@ -49,6 +49,7 @@ var ListController = BasicController.extend({
         this.editable = params.editable;
         this.noLeaf = params.noLeaf;
         this.selectedRecords = params.selectedRecords || [];
+        this.multipleRecordsSavingPromise = null;
     },
 
     //--------------------------------------------------------------------------
@@ -347,15 +348,6 @@ var ListController = BasicController.extend({
         return _.extend(env, {domain: record.getDomain()});
     },
     /**
-     * @private
-     * @returns {boolean}
-     */
-    _inMultipleRecordEdition: function (recordId) {
-        var record = this.model.get(recordId, { raw: true });
-        var recordIds = _.union([recordId], this.selectedRecords);
-        return recordIds.length > 1 && record.res_id;
-    },
-    /**
      * Only display the pager when there are data to display.
      *
      * @override
@@ -366,10 +358,16 @@ var ListController = BasicController.extend({
         return !!state.count;
     },
     /**
+     * Saves multiple records at once. This method is called by the _onFieldChanged method
+     * since the record must be confirmed as soon as the focus leaves a dirty cell.
+     * Pseudo-validation is performed with registered modifiers.
+     * Returns a promise that is resolved when confirming and rejected in any other case.
+     *
      * @private
      * @param {string} recordId
      * @param {Object} node
      * @param {Object} changes
+     * @returns {Promise}
      */
     _saveMultipleRecords: function (recordId, node, changes) {
         var self = this;
@@ -383,22 +381,42 @@ var ListController = BasicController.extend({
             }
             return result;
         }, []);
-        var message = _.str.sprintf(
-            _t('Do you want to set the value on the %d valid selected records?'),
-            validRecordIds.length);
-        if (recordIds.length !== validRecordIds.length) {
-            var nbInvalid = recordIds.length - validRecordIds.length;
-            message += ' ' + _.str.sprintf(_t('(%d invalid)'), nbInvalid);
-        }
-        Dialog.confirm(this, message, {
-            confirm_callback: function () {
-                self.model.saveRecords(recordId, validRecordIds)
-                    .then(function () {
-                        self._updateButtons('readonly');
-                        var state = self.model.get(self.handle);
-                        self.renderer.updateState(state, {});
-                    });
-            },
+        const nbInvalid = recordIds.length - validRecordIds.length;
+
+        return new Promise((resolve, reject) => {
+            const rejectAndDiscard = () => {
+                this.model.discardChanges(recordId);
+                return this._confirmSave(recordId).then(reject);
+            };
+            if (validRecordIds.length > 0) {
+                let message;
+                if (nbInvalid === 0) {
+                    message = _.str.sprintf(
+                        _t("Do you want to set the value on the %d selected records?"),
+                        validRecordIds.length);
+                } else {
+                    message = _.str.sprintf(
+                        _t("Do you want to set the value on the %d valid selected records? (%d invalid)"),
+                        validRecordIds.length, nbInvalid);
+                }
+                Dialog.confirm(this, message, {
+                    confirm_callback: () => {
+                        this.model.saveRecords(recordId, validRecordIds)
+                            .then(() => {
+                                this._updateButtons('readonly');
+                                const state = this.model.get(this.handle);
+                                this.renderer.updateState(state, {});
+                                resolve();
+                            })
+                            .guardedCatch(rejectAndDiscard);
+                    },
+                    cancel_callback: rejectAndDiscard,
+                });
+            } else {
+                Dialog.alert(this, _t("No valid record to save"), {
+                    confirm_callback: rejectAndDiscard,
+                });
+            }
         });
     },
     /**
@@ -409,10 +427,11 @@ var ListController = BasicController.extend({
      */
     _saveRecord: function (recordId) {
         var record = this.model.get(recordId, { raw: true });
-        if (record.isDirty() && this._inMultipleRecordEdition(recordId)) {
+        if (record.isDirty() && this.renderer.inMultipleRecordEdition(recordId)) {
             // do not save the record (see _saveMultipleRecords)
-            return Promise.resolve();
-
+            const prom = this.multipleRecordsSavingPromise || Promise.reject();
+            this.multipleRecordsSavingPromise = null;
+            return prom;
         }
         return this._super.apply(this, arguments);
     },
@@ -621,14 +640,15 @@ var ListController = BasicController.extend({
      */
     _onFieldChanged: function (ev) {
         ev.stopPropagation();
-        var self = this;
+        const recordId = ev.data.dataPointID;
 
-        if (this._inMultipleRecordEdition(ev.data.dataPointID)) {
+        if (this.renderer.inMultipleRecordEdition(recordId)) {
             // deal with edition of multiple lines
-            var _onSuccess = ev.data.onSuccess;
-            ev.data.onSuccess = function () {
-                Promise.resolve(_onSuccess()).then(function () {
-                    self._saveMultipleRecords(ev.data.dataPointID, ev.target.__node, ev.data.changes);
+            const _onSuccess = ev.data.onSuccess;
+            ev.data.onSuccess = () => {
+                Promise.resolve(_onSuccess()).then(() => {
+                    const savedRecordsPromise = this._saveMultipleRecords(ev.data.dataPointID, ev.target.__node, ev.data.changes);
+                    this.multipleRecordsSavingPromise = savedRecordsPromise;
                 });
             };
         }
diff --git a/addons/web/static/src/js/views/list/list_editable_renderer.js b/addons/web/static/src/js/views/list/list_editable_renderer.js
index 979e0a41496..3943446d9b6 100644
--- a/addons/web/static/src/js/views/list/list_editable_renderer.js
+++ b/addons/web/static/src/js/views/list/list_editable_renderer.js
@@ -289,6 +289,18 @@ ListRenderer.include({
         return null;
     },
     /**
+     * Returns whether the list is in multiple record edition from a given record.
+     *
+     * @private
+     * @param {string} recordId
+     * @returns {boolean}
+     */
+    inMultipleRecordEdition: function (recordId) {
+        const record = this._getRecord(recordId) || {};
+        const recordIds = [...new Set([recordId, ...this.selection])];
+        return this.editable && recordIds.length > 1 && record.res_id;
+    },
+    /**
      * Removes the line associated to the given recordID (the index of the row
      * is found thanks to the old state), then updates the state.
      *