"When dfdl:lengthKind is 'explicit' (and dfdl:length is an expression), 'delimited', 'prefixed', 'pattern' the data value is padded to the length given by the XSD minLength facet for type 'xs:string' or dfdl:textOutputMinLength  property for other types."

My concern is the case where dfdl:lengthKind is 'explicit' and dfdl:length is an expression.

Example 1:

Suppose my infoset element contains an element at path '../x' of type  xs:string containing 10 characters "1234567890"

Suppose the length expression evaluates to 20, and lengthUnits is 'characters'

Suppose the XSD minLength facet is 100.

Suppose the textPadKind is padChar.

The above sentence says the target length would be 100 and we would pad to length 100, not 20, and there is no error.

I want to be sure this is correct and what we intended.

To me this seems inconsistent with what we have stated in Erratum 5.18 which says that whether or not the length is a constant or an expression, this element is treated as fixed length, and when unparsing, the length expression is evaluated, not ignored.

It's not  technically incorrect in erratum 5.18 because that doesn't deal with this minLength complexity.  It's just not terribly clear. We may want to update this sentence of the spec, and the erratum to both use the term target length, which is in our glossary.

Furthermore,

In this case, the dfdl:contentLength for this element should return 100 for units 'characters'.

In this case the dfdl:valueLength for this element should return 10 for units 'characters'

Expression fn:string-length(../x) should return 10.

The length expression value of 20 is effectively being ignored because it is less than the minLength. The length expression *would* be used if it was greater than the minLength.

Example 2:

My infoset contains an element at path "../x" of type xs:string of length 200

The length expression evaluates to 20

dfdl:truncateSpecifiedLengthString is true

XSD minLength is 40.

In this case I believe we would have a target length of 40, and we would truncate the string to length 40.

dfdl:contentLength of this element is 40

dfdl:valueLength of this element is 40

Expression fn:string-length(../x) should return 200.

Is this the correct interpretation?

Example 3:

Same as example 2, except XSD minLength is 0.

Now the target length would be 20 and we would truncate the length to 20.

dfdl:contentLength of this element is 20 characters

dfdl:valueLength of this element is 20 characters.

Expression fn:string-length(../x) should return 200.

Is this the correct interpretation?