[IMP]mail_ux: avatar image loading time

mail_ux/static/src/core/common/res_users_patch.js

@@ -0,0 +1,7 @@
+import { fields } from "@mail/core/common/record";
+import { ResUsers } from "@mail/core/common/res_users_model";
+import { patch } from "@web/core/utils/patch";
+
+patch(ResUsers.prototype, {
+    write_date: fields.Datetime(),
+});

mail_ux/static/src/views/web/fields/avatar/avatar_patch.js

@@ -0,0 +1,37 @@
+import { Avatar } from "@mail/views/web/fields/avatar/avatar";
+import { useState } from "@odoo/owl";
+import { useService } from "@web/core/utils/hooks";
+import { patch } from "@web/core/utils/patch";
+import { imageUrl } from "@web/core/utils/urls";
+
+patch(Avatar.prototype, {
+    setup() {
+        super.setup();
+        this.store = useState(useService("mail.store"));
+    },
+
+    /**
+     * Builds the avatar image URL including a `unique` cache-buster when the
+     * record's `write_date` is available in the mail store. This allows the
+     * browser to cache avatars as immutable resources (up to 1 year), avoiding
+     * a conditional HTTP request on every page load.
+     *
+     * Falls back to the plain URL (current Odoo behaviour) when `write_date`
+     * is not yet known in the store.
+     */
+    get avatarSrc() {
+        const { resModel, resId } = this.props;
+        let writeDate;
+
+        if (resModel === "res.users") {
+            writeDate = this.store["res.users"].get(resId)?.partner_id?.write_date;
+        } else if (resModel === "res.partner") {
+            writeDate = this.store["res.partner"].get(resId)?.write_date;
+        }
+
+        if (writeDate) {
+            return imageUrl(resModel, resId, "avatar_128", { unique: writeDate });
+        }
+        return `/web/image/${resModel}/${resId}/avatar_128`;
+    },
+});

mail_ux/static/src/views/web/fields/avatar/avatar_patch.xml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<templates xml:space="preserve">
+
+    <t t-name="mail.Avatar" t-inherit="mail.Avatar" t-inherit-mode="primary">
+        <xpath expr="//img" position="attributes">
+            <attribute name="t-att-src">avatarSrc</attribute>
+            <attribute name="t-attf-src"/>
+        </xpath>
+    </t>
+
+</templates>