Strange behavior with separators

[Patrick Grandjean]

Hi all!

I am having a strange behavior with Apache Daffodil and would like to check
with you if this is normal.

Here is the XSD (named Foo.dfdl.xsd):
START ===================

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema";
           xmlns:dfdl="http://www.ogf.org/dfdl/dfdl-1.0/";
           xmlns:foo="https://www.foo.com";
           targetNamespace="https://www.foo.com";
           elementFormDefault="unqualified">

  <xs:include 
schemaLocation="org/apache/daffodil/xsd/DFDLGeneralFormat.dfdl.xsd"
/>

  <xs:annotation>
    <xs:appinfo source="http://www.ogf.org/dfdl/";>
      <dfdl:format ref="foo:GeneralFormat" />
    </xs:appinfo>
  </xs:annotation>

  <xs:element name="ret" type="foo:Foo" />

  <xs:complexType name="Foo">
    <xs:sequence dfdl:separator="%NL;">
      <xs:element name="a" type="xs:string" minOccurs="0"
dfdl:length="1" dfdl:lengthKind="explicit">
        <xs:annotation>
          <xs:appinfo source="http://www.ogf.org/dfdl/";>
            <dfdl:discriminator testKind="pattern" testPattern="a" />
          </xs:appinfo>
        </xs:annotation>
      </xs:element>
      <xs:element name="bar" type="foo:Bar" minOccurs="0" maxOccurs="2" />
      <xs:element name="z" type="xs:string" minOccurs="0"
dfdl:length="1" dfdl:lengthKind="explicit">
        <xs:annotation>
          <xs:appinfo source="http://www.ogf.org/dfdl/";>
            <dfdl:discriminator testKind="pattern" testPattern="z" />
          </xs:appinfo>
        </xs:annotation>
      </xs:element>
    </xs:sequence>
  </xs:complexType>

  <xs:complexType name="Bar">
    <xs:sequence dfdl:separator="%NL;">
      <xs:element name="b" type="xs:string" minOccurs="0"
dfdl:length="1" dfdl:lengthKind="explicit">
        <xs:annotation>
          <xs:appinfo source="http://www.ogf.org/dfdl/";>
            <dfdl:discriminator testKind="pattern" testPattern="b" />
          </xs:appinfo>
        </xs:annotation>
      </xs:element>
      <xs:element name="c" type="xs:string" minOccurs="0"
dfdl:length="1" dfdl:lengthKind="explicit">
        <xs:annotation>
          <xs:appinfo source="http://www.ogf.org/dfdl/";>
            <dfdl:discriminator testKind="pattern" testPattern="c" />
          </xs:appinfo>
        </xs:annotation>
      </xs:element>
      <xs:element name="d" type="xs:string" minOccurs="0"
dfdl:length="1" dfdl:lengthKind="explicit">
        <xs:annotation>
          <xs:appinfo source="http://www.ogf.org/dfdl/";>
            <dfdl:discriminator testKind="pattern" testPattern="d" />
          </xs:appinfo>
        </xs:annotation>
      </xs:element>
    </xs:sequence>
  </xs:complexType>

</xs:schema>

END ===================

Here is a sample file to be parsed (named foo.txt):
START ===================

a
b
c
z

END ===================

Here is the final output of the command:
daffodil -t parse --schema Foo.dfdl.xsd foo.txt

START ===================
  <?xml version="1.0" encoding="UTF-8" ?>
  <foo:ret xmlns:foo="https://www.foo.com";>
    <a>a</a>
    <bar>
      <b>b</b>
      <c>c</c>
    </bar>
  </foo:ret>
diff:
  No differences
failure:
  Parse Error: Separator '%NL;' not found
  Schema context: sequence[1] Location line 19 column 6 in
file:/Users/pgrandjean/Development/ti-scalaxb-ticketing/src/main/resources/dfdl/Foo.dfdl.xsd
  Data location was preceding byte 6
----------------------------------------------------------------- 21
<?xml version="1.0" encoding="UTF-8" ?>
<foo:ret xmlns:foo="https://www.foo.com";>
  <a>a</a>
  <bar>
    <b>b</b>
    <c>c</c>
  </bar>
</foo:ret>
[warning] Left over data. Consumed 48 bit(s) with at least 16 bit(s)
remaining.
END ===================

The line with "z" is not parsed and Apache Daffodil complains it cannot
find separator %NL at Foo level (= line 19)

What I would expect:
- Bar.d cannot be parsed => OK since it is optional, only one instance of
Bar parsed (instead of 2)
- End type Bar parsing & go back to Foo type
- parse %NL
- parse z

If I remove maxOccurs="2" from element Foo.bar, then it works.

Could you please help me understand?

Patrick.