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Decode any percent-encoded byte in non-base64 data URLs - #310
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varun06 merged 2 commits intoOct 24, 2026
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Non-base64 payloads were percent-decoded through a String round trip, which rejected bytes that are not valid UTF-8 (e.g. %FF). Escapes are now decoded directly into bytes, as RFC 2397 allows any octet.
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Motivation and Context
In a non-base64 data URL,
Data.parseDataURLdecoded%XXescapes by converting to aStringand then to UTF-8 data. That fails for bytes that aren't valid UTF-8, even thoughRFC 2397 allows any byte:
%XXescapes are now decoded directly into bytes, without theStringround trip, so anybyte value is accepted. Malformed escapes (e.g.
%fg) still returnnil, as before.How Has This Been Tested?
Adds tests for:
data:text/plain;charset=iso-8859-7,%be%d3%be, which also returnednilbefore this change (its bytes aren't valid UTF-8);%,%F,%fg) still returningnil.Existing percent-decoding tests still pass.
swift testpasses.Breaking Changes
None.
Valuedecoding followsparseDataURL, so a JSON string like the one above nowdecodes as
.data, as other data-URL strings already do.Types of changes