Sorry for not responding to this in my previous reply.
On Wed, 2021-04-14 at 15:29 +0000, Zbigniew Jędrzejewski-Szmek wrote:
I wanted to investigate this, but unfortunately, it's hard to
check
right now, because all builds are non-reproducible (in the sense of
reproducible-builds.org), because we include the mtime of build
products in rpm metadata, so pretty much all binary rpms are
different.
I'm thinking this isn't that important. In most current RPMs, the
mtimes for files are in two places:
1. In the (main) rpm header
2. in the cpio header for the file in the payload.
I can talk about the effect on RPMCow: the mtime isn't part of the
identity of the file - it's just a content hash. When the files are
actually installed, then the resulting inode is touch'ed to the right
time. Therefore I think it's moot (MOOt?) from a CoW perspective, the
reuse can happen.
Matthew.