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Throw FormatException from Base64.TryDecodeFromChars for invalid input - #634
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Bug
The
Base64.TryDecodeFromCharspolyfill caughtFormatExceptionand returnedfalsefor invalid input. The net11 BCL only returnsfalsewhen the destination is too small; invalid input ("!!!!","AQI","AQ=I") throwsFormatException. Callers could not tell a too-small buffer from bad data, and code written against the polyfill changed behaviour on net11.Fix
Remove the
try/catchso theFormatExceptionpropagates.Test
Base64Tests.TryDecodeFromChars_Invalidasserts the exception for three invalid inputs andTryDecodeFromChars_TooSmallpins thefalsepath. AllBase64Testspass on net48 and net8.0 (polyfill) and net11.0 (BCL).