add pos_attribute_image_lazy

pos_attribute_image_lazy/README.md

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+# POS Attribute Image Lazy Loading
+
+Keeps `product.attribute.value` images out of the `pos.session.load_pos_data`
+payload.
+
+## The problem
+
+`pos.session._get_attributes_by_ptal_id()` inlines the base64 `image` of every
+attribute value of a `create_variant='no_variant'` attribute, **once per
+attribute line** referencing it. With a handful of photo sized images this grows
+without bound and the request dies while serialising the response:
+
+```
+File "werkzeug/wrappers/response.py", line 327, in set_data
+    value = value.encode(self.charset)
+MemoryError
+```
+
+The browser only sees `ConnectionLostError` on
+`/web/dataset/call_kw/pos.session/load_pos_data`, with no traceback in the POS.
+
+Note that `product.attribute.value.image` is capped at 70x70 upstream, but
+`product.template.attribute.value.image` is a related field declared without
+`max_width`/`max_height`, so uploading through a product template's attribute
+lines stores the original untouched.
+
+## The fix
+
+The POS front end never reads those bytes. `point_of_sale.ColorProductAttribute`
+only tests the field for truthiness and renders the swatch from
+`/web/image/product.template.attribute.value/<id>/image`. Reading under
+`bin_size` returns the attachment size instead of its content, which is still
+truthy, so nothing changes visually.
+
+Measured on a production database with 224 images of ~1 MB:
+
+| | `load_pos_data` payload |
+|---|---|
+| Without the module | 145.93 MB |
+| With the module | 0.51 MB |

pos_attribute_image_lazy/__init__.py

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+from . import models

pos_attribute_image_lazy/__manifest__.py

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+{
+    "name": "POS Attribute Image Lazy Loading",
+    "version": "17.0.1.0.0",
+    "summary": "Avoid embedding attribute value images in the POS session payload",
+    "author": "Criptomart",
+    "website": "https://criptomart.net",
+    "license": "AGPL-3",
+    "category": "Point of Sale",
+    "depends": ["point_of_sale"],
+    "data": [],
+    "installable": True,
+}

pos_attribute_image_lazy/models/__init__.py

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+from . import pos_session

pos_attribute_image_lazy/models/pos_session.py

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+from odoo import models
+
+
+class PosSession(models.Model):
+    _inherit = "pos.session"
+
+    def _get_attributes_by_ptal_id(self):
+        """Return the attribute values without inlining their image content.
+
+        ``point_of_sale`` reads the ``image`` field of every
+        ``product.attribute.value`` belonging to a ``no_variant`` attribute and
+        ships it, base64 encoded, inside the ``load_pos_data`` response --
+        repeated once per attribute line using that value.
+
+        The POS front end never uses those bytes: the only reader is
+        ``point_of_sale.ColorProductAttribute``, which merely tests the field
+        for truthiness and then renders the swatch from
+        ``/web/image/product.template.attribute.value/<id>/image``.
+
+        Reading with ``bin_size`` makes the ORM return the human readable
+        attachment size (e.g. ``b'827.41 Kb'``) instead of its content, so the
+        attachment is never loaded into memory. The value stays truthy, which
+        keeps the swatch rendering identical.
+        """
+        return super(
+            PosSession, self.with_context(bin_size=True)
+        )._get_attributes_by_ptal_id()