fix(models): normalize empty-string trade and position icons to None

src/polymarket/models/data/activity.py

@@ -8,7 +8,11 @@
 
 from polymarket.errors import UnexpectedResponseError
 from polymarket.models.base import BaseModel
-from polymarket.models.gamma.common import parse_epoch_seconds_optional, parse_optional_decimal
+from polymarket.models.gamma.common import (
+    empty_string_to_none,
+    parse_epoch_seconds_optional,
+    parse_optional_decimal,
+)
 from polymarket.models.types import (
     CtfConditionId,
     TokenId,
@@ -58,6 +62,11 @@ def _parse_decimal(cls, value: object) -> Decimal | None:
     def _parse_timestamp(cls, value: object) -> datetime | None:
         return parse_epoch_seconds_optional(value)
 
+    @field_validator("icon", mode="before")
+    @classmethod
+    def _normalize_icon(cls, value: object) -> object | None:
+        return empty_string_to_none(value)
+
 
 ActivityType = Literal[
     "TRADE",

src/polymarket/models/data/portfolio.py

@@ -8,6 +8,7 @@
 
 from polymarket.models.base import BaseModel
 from polymarket.models.gamma.common import (
+    empty_string_to_none,
     parse_epoch_seconds_optional,
     parse_optional_date,
     parse_optional_decimal,
@@ -100,6 +101,11 @@ def _parse_decimal(cls, value: object) -> Decimal | None:
     def _parse_end_date(cls, value: object) -> date | None:
         return parse_optional_date(value)
 
+    @field_validator("icon", mode="before")
+    @classmethod
+    def _normalize_icon(cls, value: object) -> object | None:
+        return empty_string_to_none(value)
+
     def _repr_html_(self) -> str:
         from polymarket._jupyter import card, safe_html_repr, truncate_mid
 
@@ -170,6 +176,11 @@ def _parse_timestamp(cls, value: object) -> datetime | None:
     def _parse_end_date(cls, value: object) -> date | None:
         return parse_optional_date(value)
 
+    @field_validator("icon", mode="before")
+    @classmethod
+    def _normalize_icon(cls, value: object) -> object | None:
+        return empty_string_to_none(value)
+
 
 class ComboPositionMarketEvent(BaseModel):
     event_id: str | None = None

tests/unit/test_data_activity.py

@@ -15,7 +15,7 @@
     YieldActivity,
 )
 from polymarket.errors import UnexpectedResponseError
-from polymarket.models.data.activity import parse_activities, parse_activity
+from polymarket.models.data.activity import Trade, parse_activities, parse_activity
 
 _CONDITION_ID = "0x5c19f205507ce03ff5f3be08a8090a5969ea6870cc07b902a4ca2e61dfe48fdd"
 
@@ -137,6 +137,16 @@ def test_market_event_empty_icon_normalizes_to_none() -> None:
     assert activity.icon is None
 
 
+def test_trade_model_empty_icon_normalizes_to_none() -> None:
+    trade = Trade.parse_response({"icon": ""})
+    assert trade.icon is None
+
+
+def test_trade_model_keeps_populated_icon() -> None:
+    trade = Trade.parse_response({"icon": "https://example.test/icon.png"})
+    assert trade.icon == "https://example.test/icon.png"
+
+
 def test_market_event_variants_parse() -> None:
     for activity_type, expected_class in [
         ("SPLIT", SplitActivity),

tests/unit/test_data_models.py

@@ -7,12 +7,14 @@
 from polymarket.errors import UnexpectedResponseError
 from polymarket.models.data import (
     BuilderVolumeEntry,
+    ClosedPosition,
     ComboPosition,
     Holder,
     LiveVolume,
     MetaHolder,
     OpenInterest,
     PortfolioValue,
+    Position,
     TradedMarketCount,
 )
 
@@ -159,6 +161,26 @@ def test_traded_market_count_parses_payload() -> None:
     assert count.traded == 42
 
 
+def test_position_empty_icon_normalizes_to_none() -> None:
+    position = Position.parse_response({"conditionId": _CTF_CONDITION_ID, "icon": ""})
+
+    assert position.icon is None
+
+
+def test_position_keeps_populated_icon() -> None:
+    position = Position.parse_response(
+        {"conditionId": _CTF_CONDITION_ID, "icon": "https://example.test/icon.png"}
+    )
+
+    assert position.icon == "https://example.test/icon.png"
+
+
+def test_closed_position_empty_icon_normalizes_to_none() -> None:
+    position = ClosedPosition.parse_response({"conditionId": _CTF_CONDITION_ID, "icon": ""})
+
+    assert position.icon is None
+
+
 def test_builder_volume_entry_renames_dt_to_bucket_at() -> None:
     entry = BuilderVolumeEntry.parse_response(
         {