[Karman580]

Description

Closes #19274

Root cause

CastFunctionUtils.castDoubleToInt rounded (float) value. A FLOAT keeps only 24 significand bits, so in-range doubles above 2^24 can change before they are rounded, and doubles just below a .5 tie can be moved onto the tie. For example, 123456789.0 came out as 123456792 and 2.4999999999 as 3. Every DOUBLE to INT32 cast goes through this method: the per-value and batch column casts in the tree and table models, and table-model constant folding.

Change

- return Math.round((float) value);
+ return (int) Math.round(value);

This matches castDoubleToLong and the documented rule for DOUBLE to INT32 ("Math.round()"). The range check above it is unchanged. It limits the value to [Integer.MIN_VALUE, Integer.MAX_VALUE], so Math.round(value) stays within int range and the cast from long cannot overflow. Half values keep their existing behaviour (2.5 -> 3, -2.5 -> -2), and out-of-range values still throw.

Tests

New cases in CastFunctionUtilsTest:

• castDoubleToIntKeepsDoublePrecision: 16777217, ±123456789, 2147483000, 2147483646, -2147483647, Integer.MAX_VALUE, Integer.MIN_VALUE, 2.4999999999 and 100000001.5
• castDoubleToIntRoundsHalfUp: 2.5, -1.5 and -2.5
• castDoubleToIntJustAboveMax / castDoubleToIntJustBelowMin: 2147483648.0 and -2147483649.0 throw SemanticException

Results with ./mvnw -pl iotdb-core/calc-commons test -Dtest=CastFunctionUtilsTest (Temurin JDK 25.0.2, macOS arm64):

Before the fix:

[ERROR] Tests run: 23, Failures: 1, Errors: 0, Skipped: 0
[ERROR]   CastFunctionUtilsTest.castDoubleToIntKeepsDoublePrecision:79 expected:<16777217> but was:<16777216>

After the fix:

[INFO] Tests run: 23, Failures: 0, Errors: 0, Skipped: 0
[INFO] BUILD SUCCESS

./mvnw -pl iotdb-core/calc-commons test (whole module) also passes: Tests run: 91, Failures: 0, Errors: 0, Skipped: 0. Spotless check passes.

I also ran the SQL from #19274 on a standalone 2.0.11-SNAPSHOT server with the patched class. Tree, table and constant-folded casts now return the same values as CAST(... AS INT64):

|  1.6777217E7|  16777217|  16777217|
| 1.23456789E8| 123456789| 123456789|
|-1.23456789E8|-123456789|-123456789|
|   2.147483E9|2147483000|2147483000|
| 2.4999999999|         2|         2|
|1.000000015E8| 100000002| 100000002|

SELECT CAST(2147483648.0 AS INT32) still fails with 701: Double value 2147483648.000000 is out of range of integer value., and TRY_CAST(-2147483649.0 AS INT32) returns null.

Not run locally: the integration-test suites (IoTDBCastFunctionIT, IoTDBCastFunctionTableIT) and the datanode module tests. I checked that no existing IT asserts the old FLOAT-rounded values.

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This PR has:

• been self-reviewed.
• added unit tests or modified existing tests to cover new code paths, ensuring the threshold
  for code coverage.

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Key changed/added classes (or packages if there are too many classes) in this PR

• CastFunctionUtils (calc-commons)
• CastFunctionUtilsTest