Module gff_compare 

Comparing a rewritten GFF tree against its original. Comparing a GFF tree against the one it was derived from.

A typed view reads a GFF, models some of it, and writes it back. Two questions decide whether that was faithful, and neither can be answered by looking at the view alone:

• Did every field it rewrote keep the value the original had?
• Did it write a label the original never had?

Both are pure tree work: which labels are present, and whether the values under them match. Nothing here knows what a module or a creature is, which is why it sits in this crate rather than above it.

Both the test suite and vanilla-inspector use these. That is the point: if the tool and the tests grew separate implementations, the tool’s verdict would quietly stop meaning what the tests’ verdict means, which is the same parallel-definition drift that has produced real defects here before.

What this does not decide

Whether a difference is a defect. A view is a projection and is entitled to drop fields, and a label written but absent from every file may be a field the engine omits at its default rather than a wrong label. The caller supplies that judgement; this module supplies the observation.

Structs

CaseVariantGroup

A family of labels that differ only by letter case.

LabelCensus

Which labels a view writes that no file was seen to contain, accumulated over a corpus.

LabelObservation

What a corpus was seen to carry under one label.

LeafPathSplit

One leaf label the view models at some of its corpus paths and not others.

ValueDifference

One field whose value changed between the original and the rewrite.

Enums

InventedLabels

Whether a corpus can decide the invented-label question at all.

Functions

value_differences

Reports every field the rewrite changed the value of.