would-invalidate-signatures

All codes

• Type: error (laminapdf_save::SaveError::WouldInvalidateSignatures)
• Kind: security (signatures block the call)

What happened

The save planner refused a save because it would break one or more signatures. Either it was a full rewrite of a signed document, or its pending changes or rewrite reasons conflict with the document’s signatures: a DocMDP, FieldMDP or usage-rights restriction, or a repaired or encrypted base. Nothing was written.

Why

A signature covers the bytes of the file as it was signed (ISO 32000-2 §12.8). A full rewrite moves those bytes, and a change a certification forbids invalidates it even when appended. Lamina PDF never breaks a signature without an explicit override.

How to fix

Save with SaveMode::Auto or SaveMode::Incremental when the constraint allows it. Otherwise ask the user, naming the signatures in the error, and save again with SaveOptions::with_invalidate_signatures(true): the invalidated signatures’ values and /Perms entries are removed and SaveReport::invalidated lists them.

Example

let err = doc.save(&mut out, &SaveOptions::new().with_mode(SaveMode::FullRewrite)).unwrap_err();
assert_eq!(err.code(), "would-invalidate-signatures");

Data fields

• signatures: every signature, as { field, kind, value, revision, covers } (field ID, kind, signature dictionary as num gen, revision, covered length).
• rewrite_reasons: why only a full rewrite is safe, if anything says so.
• violations: pending changes a signature’s restriction forbids, as { class, restriction, signature }.
• signatures_unknown: part of the form couldn’t be followed, so there may be signatures beyond signatures.

None of them hold document text.