NFC

Every string and key is converted to Unicode Normalization Form C as it is read, on insert and in queries, so the two spellings of "é" are one string. What a document reads back is the normalized form, not the text that was inserted.

The cost is paid while parsing: ASCII, and text that is already normalized, are recognized without rebuilding anything; the rest is converted, which allocates. Normalization can also make two keys of one object equal, and the document is then rejected with RejectReason.DUPLICATE_KEY. A key or string whose normalized form has more than 30 combining marks in a row is rejected with RejectReason.LIMIT_EXCEEDED (SPEC.md §1.3), in a document and equally in a query, a type name or path, or a key given to a lookup.