Is hSetBinaryMode required for ByteString I/O?

[ghost]

This issue relates to the Haddock API documentation. Is the following note about Data.ByteString.Lazy.hGetContents correct or is it out of date?

Note: the Handle should be placed in binary mode with hSetBinaryMode for hGetContents to work correctly.

If it is out of date, please consider adding a statement somewhere in the documentation that hSetBinaryMode is definitely not required, for avoidance of confusion.

This also affects the following issue in the process package.

[sjakobi]

I suspect this might be related to #13. I believe the effects of hSetBinaryMode are currently simply not respected.

[Bodigrim]

The note was added in 2b4485b, which points to https://gitlab.haskell.org/ghc/ghc/-/issues/3808 and leads to

bytestring/Data/ByteString.hs

Lines 1898 to 1914 in d79b997

	hGetSome hh i
	#if MIN_VERSION_base(4,3,0)
	| i > 0 = createAndTrim i $ \p -> hGetBufSome hh p i
	#else
	| i > 0 = let
	loop = do
	s <- hGetNonBlocking hh i
	if not (null s)
	then return s
	else do eof <- hIsEOF hh
	if eof then return s
	else hWaitForInput hh (-1) >> loop
	-- for this to work correctly, the
	-- Handle should be in binary mode
	-- (see GHC ticket #3808)
	in loop
	#endif

These days bytestring requires base>=4.3, so hIsEOF is not used anymore and the warning about hSetBinaryMode does not apply. A PR removing #if MIN_VERSION_base(4,3,0) and warnings is very welcome.