[FIX] web: format function missing in percentage widget

The format function was missing for the percentage widget type, so
`field_utils.parse[this.formatType]` (see [1]) resolved as
`undefined` which is not a function and so raised an error when
the user was trying to update the field.

This PR add that parsing function. Both `xx%` and `0.xx` are
understood by the parser and resolve to the correct float value.

opw-1895979

[1] https://github.com/odoo/odoo/blob/e220721a8ee80c02fe5aba5ed8c9f3f4ae54ea97/addons/web/static/src/js/fields/abstract_field.js#L399

closes odoo/odoo#28431

1 files changed, 17 insertions, 0 deletions

diff --git a/addons/web/static/src/js/fields/field_utils.js b/addons/web/static/src/js/fields/field_utils.js
index 9d40c88019d..bbdee83c4f9 100644
--- a/addons/web/static/src/js/fields/field_utils.js
+++ b/addons/web/static/src/js/fields/field_utils.js
@@ -587,6 +587,22 @@ function parseFloatTime(value) {
 }
 
 /**
+ * Parse a String containing a percentage and convert it to float.
+ * The percentage can be a regular xx.xx float or a xx%.
+ *
+ * @param {string} value
+ *                The string to be parsed
+ * @returns {float}
+ * @throws {Error} if the value couldn't be converted to float
+ */
+function parsePercentage(value) {
+    if (value.slice(-1) === '%') {
+        return parseFloat(value.slice(0, -1)) / 100;
+    }
+    return parseFloat(value);
+}
+
+/**
  * Parse a String containing integer with language formating
  *
  * @param {string} value
@@ -668,6 +684,7 @@ return {
         many2one: parseMany2one,
         monetary: parseMonetary,
         one2many: _.identity,
+        percentage: parsePercentage,
         reference: parseMany2one,
         selection: _.identity, // todo
         text: _.identity, // todo