HHH-19969 - Fix and test for error in camel to snake case conversion

[jrenaat]

---

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license
and can be relicensed under the terms of the LGPL v2.1 license in the future at the maintainers' discretion.
For more information on licensing, please check here.

---

https://hibernate.atlassian.net/browse/HHH-19969

[beikov]

It seems to me that this would be simpler and avoid creating the char array copy.

Suggested change

	final char[] copy = builder.toString().toCharArray();
	int builderIndex = 1;
	for ( int i = 1; i <= copy.length - 1; i++ ) {
	if ( isUnderscoreRequired(
	copy[i - 1],
	copy[i],
	i == copy.length - 1 ? '*' : copy[i + 1] ) // add some fictitious final character
	) {
	builder.insert( builderIndex++, '_' );
	}
	builderIndex++;
	}
	for ( int i = 1; i < builder.length() - 1; i++ ) {
	if ( isUnderscoreRequired( builder.charAt( i - 1 ), builder.charAt( i ), builder.charAt( i + 1 ) ) ) {
	builder.insert( i++, '_' );
	}
	}
	if ( builder.length() > 1 && isUnderscoreRequired( copy[builder.length() - 2], copy[builder.length() - 1], '0' ) ) {
	builder.insert( builder.length() - 1, '_' );
	}

[jrenaat]

I used the char[] copy to avoid the index increment inside the for loop, which is what caused the jump over the last character (and it makes it somewhat hard to follow, and it's imo ugly (arguable))
Also, your change still uses the copy ?