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wiggleverse-ecomm/backend/app/domains/products/serialize.py
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ben.stull af72299a57
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fix(products): serialize Variant Position explicitly — INV-12 round-trip bug
A stored variant position is a CatalogVariant attribute, not a fields{} entry,
so the serializer emitted an empty Variant Position cell — which re-imports as
'reset to file order'. A non-sequential stored position (a merchant can import
explicit positions) then round-tripped to a spurious update, violating INV-12.
Emit str(variant.position) explicitly (like _write_image). The property-test
generator now assigns non-sequential positions to lock the regression, plus a
targeted test. Also wires isExportEnabled into ProductsPage (was dead code).
Both caught by the final code review.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-06-11 22:22:11 -07:00

120 lines
4.5 KiB
Python

"""Canonical serializer — CatalogProduct snapshot → canonical CSV (SD-0002 §6.5.5).
The export half of "one codec, two directions": this writes exactly the columns
codec.py/validate.py parse, in a row grammar (§6.5.1) the validator regroups
identically — so re-importing an unmodified export diffs to nothing (INV-12).
DB-free, like diff.py: it consumes the same CatalogProduct snapshot the diff
engine reads (repo.load_catalog), and the service streams the result.
"""
from __future__ import annotations
import csv
import io
from collections.abc import Iterable, Iterator
from decimal import Decimal
from .diff import CatalogProduct
from .models import (
IMAGE_COLUMNS,
OPTION_VALUE_COLUMNS,
PRODUCT_COLUMNS,
VARIANT_COLUMNS,
)
# Canonical column order: Handle, then product, option-value, variant, image
# columns. A superset of everything the parser knows (models.KNOWN_COLUMNS minus
# the #15-reserved Component columns, which export never emits).
HEADER: list[str] = [
"Handle",
*PRODUCT_COLUMNS,
*OPTION_VALUE_COLUMNS,
*VARIANT_COLUMNS,
*IMAGE_COLUMNS,
]
# field name -> column name, inverting the model registry (the parser reads
# column->field; the serializer writes field->column).
_PRODUCT_FIELD_TO_COL = {field: col for col, field in PRODUCT_COLUMNS.items()}
_VARIANT_FIELD_TO_COL = {field: col for col, field in VARIANT_COLUMNS.items()}
def _cell(value: object) -> str:
"""Serialize one value to its canonical cell text (the parse inverse)."""
if value is None:
return ""
if isinstance(value, bool):
return "TRUE" if value else "FALSE"
if isinstance(value, Decimal):
return str(value)
if isinstance(value, (list, tuple)):
return ", ".join(str(v) for v in value)
return str(value)
def catalog_to_csv(products: Iterable[CatalogProduct]) -> Iterator[str]:
"""Stream canonical CSV text, header first, one product block at a time."""
buf = io.StringIO()
writer = csv.writer(buf)
writer.writerow(HEADER)
yield _drain(buf)
for product in products:
for row in _product_rows(product):
writer.writerow([row.get(col, "") for col in HEADER])
yield _drain(buf)
def _drain(buf: io.StringIO) -> str:
text = buf.getvalue()
buf.seek(0)
buf.truncate(0)
return text
def _product_rows(product: CatalogProduct) -> list[dict[str, str]]:
"""The product's CSV rows (§6.5.1 grammar): product fields + option names on
the first row; one variant per row; images interleaved; image-only rows when
a product has more images than variants."""
base = {"Handle": product.handle, "Title": product.title}
for field, col in _PRODUCT_FIELD_TO_COL.items():
if field in product.fields:
base[col] = _cell(product.fields[field])
for slot, name in enumerate(product.option_names, start=1):
if name:
base[f"Option{slot} Name"] = name
count = max(len(product.variants), len(product.images))
rows: list[dict[str, str]] = []
for i in range(count):
# Row 0 carries the product-level fields; later rows carry only Handle.
row = dict(base) if i == 0 else {"Handle": product.handle}
if i < len(product.variants):
_write_variant(row, product, product.variants[i])
if i < len(product.images):
_write_image(row, product.images[i])
rows.append(row)
return rows
def _write_image(row: dict[str, str], image) -> None:
row["Image Src"] = image.source_url
row["Image Position"] = str(image.position)
if image.alt_text is not None:
row["Image Alt Text"] = image.alt_text
def _write_variant(row: dict[str, str], product: CatalogProduct, variant) -> None:
"""Fill a row's option-value + variant columns for one variant."""
for slot, value in enumerate(variant.options, start=1):
# Only emit an option value when the product actually has that option
# (a no-option product's single variant carries all-NULL options).
if product.option_names[slot - 1] and value is not None:
row[f"Option{slot} Value"] = value
# position is a CatalogVariant attribute, not a fields{} entry — emit it
# explicitly. An empty Variant Position cell re-imports as "reset to file
# order", so a non-sequential stored position would round-trip to an update
# (INV-12). (Like _write_image, which emits its position attribute.)
row["Variant Position"] = str(variant.position)
for field, col in _VARIANT_FIELD_TO_COL.items():
if field in variant.fields:
row[col] = _cell(variant.fields[field])