On Sat, Nov 06, 2021 at 11:15:37AM +0100, Bruno Damour wrote:

A lot of them are in the process (or already have) of adding compatibility layers to allow them to support the new version while preserving compatibility with older ones, introducing code like :

#if MIN_VERSION_base(4,16,0) word32ToWordCompat# :: Word32# -> Word# word32ToWordCompat# = word32ToWord# #else word32ToWordCompat# :: Word32# -> Word# word32ToWordCompat# x = x #endif for the functions they use (usually a small subset).

Some of the solutions appear to differ.

Is there a preferred way to make this consistently or/and avoid unnecessary code duplication ?

Since the above is what the head.hackage maintainers are doing, I assumed that's the way to go. On Sat, Nov 06, 2021 at 01:08:01PM +0100, Bruno Damour wrote:

... but I have seen this in:

base16-bytestring basement streaming-commons iproute hashtables

So it seems quite widespread… especially as a number of common libraries depend on these (persistent for example)

An updated iproute 1.7.12 is now released, using the head.hackage approach. -- Viktor.