SNOW-2392212: Fix floating point precision bug in interval_day_time_f… (#3847)

Author: sfc-gh-fhe

CHANGELOG.md

@@ -33,6 +33,7 @@
 
 #### Bug Fixes
 
+- Added a fix for floating point precision discrepancies in `interval_day_time_from_parts`.
 - Fixed a bug where writing Snowpark pandas dataframes on the pandas backend with a column multiindex to Snowflake with `to_snowflake` would raise `KeyError`.
 - Fixed a bug that `DataFrameReader.dbapi` (PuPr) is not compatible with oracledb 3.4.0. 
 

src/snowflake/snowpark/functions.py

@@ -11141,7 +11141,7 @@ def interval_day_time_from_parts(
         --------------------------
         |"INTERVAL"              |
         --------------------------
-        |1 day, 12:30:01.001000  |
+        |1 day, 12:30:01.001001  |
         --------------------------
         <BLANKLINE>
 
@@ -11208,16 +11208,16 @@ def interval_day_time_from_parts(
         cast(secs_int, "str"),
     )
 
-    has_fraction = abs(secs_part - cast(secs_int, "double")) > 1e-10
-    fractional_part = secs_part - cast(secs_int, "double")
+    has_fraction = abs(secs_part - cast(secs_int, "decimal")) > 1e-15
+    fractional_part = secs_part - cast(secs_int, "decimal")
 
     fraction_str = iff(
         has_fraction,
         concat(
             lit("."),
             lpad(
-                cast(round(fractional_part * lit(1000), 0), "str"),
-                3,
+                cast(round(fractional_part * lit(1000000), 0), "str"),
+                6,
                 lit("0"),
             ),
         ),

tests/integ/scala/test_function_suite.py

@@ -5917,3 +5917,30 @@ def test_interval_day_time_from_parts(session):
     assert result_nulls[2]["INTERVAL_RESULT"] is None
     assert result_nulls[3]["INTERVAL_RESULT"] is None
     assert result_nulls[4]["INTERVAL_RESULT"] is None
+
+    df_extreme = session.create_dataframe(
+        [[1, 0, 0, 123456789012.123456]], ["days", "hours", "mins", "secs"]
+    )
+    result_extreme = df_extreme.select(
+        interval_day_time_from_parts(
+            col("days"), col("hours"), col("mins"), col("secs")
+        ).alias("extreme_interval")
+    ).collect()
+
+    interval_result = result_extreme[0]["EXTREME_INTERVAL"]
+    assert isinstance(interval_result, timedelta)
+    total_seconds = interval_result.total_seconds()
+    expected_total = 86400 + 123456789012.123456
+    import builtins
+
+    assert builtins.abs(total_seconds - expected_total) < 1e-6
+
+    result_microsecond = df_extreme.select(
+        interval_day_time_from_parts(lit(0), lit(0), lit(0), lit(0.123456)).alias(
+            "microsecond_test"
+        )
+    ).collect()
+
+    interval_result = result_microsecond[0]["MICROSECOND_TEST"]
+    expected = timedelta(seconds=0.123456)
+    assert interval_result == expected