Stop xsd2inst building digit-facet bounds as strings

[pjfanning]

Branched from trunk, independent of #98.

The bug

SampleXmlUtil.formatDecimal derived both digit-facet bounds by building a string and parsing it back — xsd:totalDigits as that many nines, xsd:fractionDigits as "0.00...1". Both facets are positiveInteger with no ceiling of their own, so as soon as a schema asks for more digits than maxNumberOfCharsForNumbers allows, parseAsBigDecimal rejects the string the method just built:

IllegalArgumentException: Number has more than 1024 characters

and xsd2inst cannot generate a sample for the schema at all. 5.3.0 used new BigDecimal(...) here and was unaffected; the limit arrived in 5.4.0.

A minimal reproducer — nothing else in the schema:

<xs:simpleType name="constrainedDecimal">
  <xs:restriction base="xs:decimal">
    <xs:totalDigits value="2000"/>
  </xs:restriction>
</xs:simpleType>

The fractionDigits branch fails the same way at 1023.

The fix

Compute both values instead of spelling them out:

• 10^totalDigits - 1 for the widest value the facet allows;
• BigDecimal.ONE.scaleByPowerOfTen(-fractionDigits) for the increment, which only sets a scale and expands nothing.

The totalDigits bound can only narrow a min/max that is at least as wide, so it is now computed only when it can actually bind. That is what keeps 10^n away from a totalDigits far larger than any bound the schema declares — the previous code built its string of nines unconditionally, even when no min or max facet existed for it to constrain.

Behaviour for schemas within the limit is unchanged: totalDigits still pulls the seed value down to the widest value it permits.

Tests

testDigitFacetsWiderThanTheNumberLengthLimit covers both facets past the limit — it fails on trunk with the exception above. testTotalDigitsStillNarrowsTheBounds pins the normal case (seed 1000.00, totalDigits=3 → 999) and passes both before and after, so it guards the semantics rather than the fix.

Full suite: 3084 tests, 0 failures.

🤖 Generated with Claude Code