Wrong SourceSpan with lazy continuation lines #337

Hi !
I'm using commonmark-java to highlight delimiters in a RichTextFX editor, and using SourceSpan to compute positions.
I have an issue with 2 examples given by commonmark specification.

Example 292

> 1. > Blockquote
continued here.

Actual behavior (printing SourceSpan in visitChildren)

• Text{literal=Blockquote} [SourceSpan{line=0, column=7, length=10}]
• SoftLineBreak{} []
• Text{literal=continued here.} [SourceSpan{line=1, column=0, length=15}]
• Paragraph{} [SourceSpan{line=0, column=7, length=10}, SourceSpan{line=1, column=0, length=15}]
• BlockQuote{} [SourceSpan{line=0, column=5, length=12}, SourceSpan{line=1, column=5, length=10}]
• ListItem{} [SourceSpan{line=0, column=2, length=15}, SourceSpan{line=1, column=2, length=13}]
• OrderedList{} [SourceSpan{line=0, column=2, length=15}, SourceSpan{line=1, column=2, length=13}]
• BlockQuote{} [SourceSpan{line=0, column=0, length=17}, SourceSpan{line=1, column=0, length=15}]
• Document{} []

I don't understand sourceSpans or the second line. It seems to me that BlockQuote/ListItem/OrderedList should start at column 0 for line 1.

Example 250

> > > foo
bar

• Text{literal=foo} [SourceSpan{line=0, column=6, length=3}]
• SoftLineBreak{} []
• Text{literal=bar} [SourceSpan{line=1, column=0, length=3}]
• Paragraph{} [SourceSpan{line=0, column=6, length=3}, SourceSpan{line=1, column=0, length=3}]
• BlockQuote{} [SourceSpan{line=0, column=4, length=5}, SourceSpan{line=1, column=4, length=-1}]
• BlockQuote{} [SourceSpan{line=0, column=2, length=7}, SourceSpan{line=1, column=2, length=1}]
• BlockQuote{} [SourceSpan{line=0, column=0, length=9}, SourceSpan{line=1, column=0, length=3}]
• Document{} []

I don't understand sourceSpan for the 3 BlockQuotes, some of them have negative length. It seems to me that all BlockQuotes should start at column 0 for line 1.

And If I add a character after bar

> > > foo
bars

• Text{literal=foo} [SourceSpan{line=0, column=6, length=3}]
• SoftLineBreak{} []
• Text{literal=bars} [SourceSpan{line=1, column=0, length=4}]
• Paragraph{} [SourceSpan{line=0, column=6, length=3}, SourceSpan{line=1, column=0, length=4}]
• BlockQuote{} [SourceSpan{line=0, column=4, length=5}] MISSING SOURCE SPACE?
• BlockQuote{} [SourceSpan{line=0, column=2, length=7}, SourceSpan{line=1, column=2, length=2}]
• BlockQuote{} [SourceSpan{line=0, column=0, length=9}, SourceSpan{line=1, column=0, length=4}]
• Document{} []

In this case, I lose the deepest BlockQuote sourceSpan for line 1

Thank you for your help.