Function staged_fallbacks 

pub fn staged_fallbacks(
    work_tree: &Path,
    index_path: &Path,
    common_dir: &Path,
    hash: Kind,
    ignore_case: bool,
) -> Vec<StagedAttributes>

The .gitattributes files git would read from the index for check-in.

One entry per .gitattributes recorded in the index whose working-tree file is absent; a file that is present wins outright on the check-in side, so it is not listed here at all. The name is compared the way git looks it up: byte-exact, or ASCII-case-folded when core.ignorecase is set — the same split the resolver itself applies to pattern matching.

Everything that cannot be read answers with an empty list rather than an error, and that direction is deliberate: the resolver’s one consumer that must never grow a false refusal is the filter, and a missing fallback only ever reproduces the pre-2026-08-05 behaviour. status reports an unreadable index through its own undetermined section, not through this.