vbhanuchander-lang opened a new pull request, #7744:
URL: https://github.com/apache/hop/pull/7744
Addresses #6111.
`BigDecimal.valueOf(double)` is specified as `new
BigDecimal(Double.toString(val))`, and `Double.toString()` switches to
scientific notation from 10<sup>7</sup> onwards. For `55487400.0` it returns
`"5.54874E7"`, which parses into an unscaled value of 554874 with a scale of
`-2`. It is that negative scale which makes `BigDecimal.toString()` render the
value as `5.54874E+7` again:
```java
BigDecimal bd = BigDecimal.valueOf(55487400.0);
bd.scale(); // -2
bd.toString(); // "5.54874E+7"
bd.toPlainString(); // "55487400"
```
So every consumer that serializes a BigNumber through `toString()` emits
scientific notation for a value that started out as plain digits:
- JDBC drivers that inline statement parameters — the Table Output `INSERT`
in the reported case
- `writeBigNumber()`, used by the binary row serialization
- `getDataXml()`, used by the XML data serialization
The formatting layer is not involved: both default masks (`####0.0#########`
and `######0.0###################`) render the value as `55487400.0` correctly.
### Change
The four `Double` to `BigDecimal` conversions in `ValueMetaBase` —
`getBigNumber()` for `TYPE_NUMBER` across its three storage types, and
`convertStringToBigNumber()` — now go through a single helper:
```java
protected static BigDecimal convertDoubleToBigNumber(double number) {
BigDecimal bigDecimal = BigDecimal.valueOf(number);
return bigDecimal.scale() < 0 ? bigDecimal.setScale(0) : bigDecimal;
}
```
Rescaling upwards from a negative scale is exact, so no rounding mode is
required, no `ArithmeticException` is possible, and the numeric value is
unchanged.
### Compatibility
- Values that already convert to a non-negative scale are returned
untouched, scale included.
- The string conversion paths format through `DecimalFormat` and never
emitted scientific notation. Their output is unchanged, and a regression test
pins that down.
- BigNumber comparison in `ValueMetaBase` uses `compareTo()`, which is
scale-insensitive, so ordering and equality semantics are unaffected.
- The XML and binary serialized forms do change for affected values, from
`5.54874E+7` to `55487400`. Both round-trip correctly, since `readBigNumber()`
parses whatever was written.
### Tests
Eight tests added to `ValueMetaBaseTest`:
- the reported value, and a range of magnitudes including negatives and
2<sup>53</sup>
- the untouched-scale guarantee, asserted with scale-sensitive `equals()`
rather than `compareTo()`
- the `convertData()` metadata-change path a Select Values transform performs
- the `writeBigNumber()` / `readBigNumber()` round trip
- `getDataXml()`
- a regression guard on the `DecimalFormat` string path
### Verification
`./mvnw -pl core test` — 1039 tests, 0 failures, 0 errors. `spotless:check`
and `apache-rat:check` both pass. The full `mvn clean install` was not run
locally; relying on CI for the complete build.
### Note for reviewers
`ValueDataUtil.ceil()`, `floor()`, `abs()` and `sqrt()` build BigNumber
results with `BigDecimal.valueOf(Math.xxx(...))` and can produce the same
negative scale. I left them out to keep this change focused, since sharing the
helper across packages would mean widening its visibility. Happy to follow up
in a separate PR if you would like that covered.
------------------------
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