fix(traces): reject a float time whose nanosecond value overflows

A finite float like 1e308 becomes infinite once scaled to nanoseconds, so
round() raised instead of the value falling back to the derived time.

Author: turnipdabeets

posthog/test/tracing/test_sanitize.py

@@ -50,6 +50,7 @@ def test_converts_float_seconds(self):
             "1700000000",
             float("nan"),
             float("inf"),
+            1e308,
             -1,
             MAX_TIMESTAMP_NS // 10**9 + 1,
             datetime(1960, 1, 1, tzinfo=timezone.utc),

posthog/tracing/_sanitize.py

@@ -76,9 +76,10 @@ def to_epoch_ns(value: Any) -> Optional[int]:
     elif isinstance(value, int):
         ns = value * 10**9
     elif isinstance(value, float):
-        if not math.isfinite(value):
+        scaled = value * 1e9
+        if not math.isfinite(scaled):
             return None
-        ns = int(round(value * 1e9))
+        ns = int(round(scaled))
     else:
         return None
     if ns < MIN_TIMESTAMP_NS or ns > MAX_TIMESTAMP_NS: