Make cobertura parser tolerate empty arrays

[gregorio-gerardi]

This will fix #82 along with some other potential errors.

Problem

the cobertura spec allows some empty tags like <!ELEMENT packages (package*)>, where package* means 0 or more package elements.

An xml like the one in the linked issue

<?xml version="1.0" ?>
<!DOCTYPE coverage SYSTEM "http://cobertura.sourceforge.net/xml/coverage-04.dtd">
<coverage lines-valid="0" lines-covered="0" line-rate="NaN" branches-valid="0" branches-covered="0" branch-rate="NaN" timestamp="1726170429312" complexity="0" version="0.1">
  <sources>
    <source>/Users/gregoriogerardi/Documents/dashjs</source>
  </sources>
  <packages>
  </packages>
</coverage>

Is an example of hoy the tag packages could be empty and still valid.

The action does not handle this scenario, it assumes that all lists will be defined (i.e. have at least one element).

Solution

I went over the spec, and tweaked all the typescript definitions related to empty lists. An empty list in the xml will end up as an undefined key in its parent typescript interface, so making all of them conditional is the correct approach based on how the xml parser works. Also, for every list that is not part of https://github.com/clearlyip/code-coverage-report-action/blob/main/src/utils.ts#L49-L53 I also added an optional type to be either an array or a single element.

[tm1000]

Thanks @gregorio-gerardi sorry for the delay!