[MacPorts] #47755: Broken symlink left by select code when selected port is deactivated causes poppler and other ports using aclocal to fail during configuration.

[Lawrence Velázquez]

On Jun 24, 2015, at 8:02 PM, Ryan Schmidt <ryandesign at macports.org> wrote:

> On Jun 24, 2015, at 5:10 PM, Christopher Ramos wrote:
> 
>> Perhaps it would be feasible to employ an agent or daemon that logs
>> all changes to a user's installation. That way, if it's ever bungled
>> by an "outside force," the user could do something like "sudo port
>> revert snapshot-06222015". This would remove any files not
>> registered by the daemon to have been present at the time of the
>> requested snapshot; if need be, previously installed or files (or
>> files that were in a different state) would retrieved from the
>> Internet.
> 
> A daemon to detect such actions is an interesting suggestion. This
> could adversely affect performance. I'm also not sure how we would
> instruct the daemon what changes are ok and what changes aren't. For
> example, installing /opt/local/lib/libsomething.dylib without using
> MacPorts would not be ok, but creating /opt/local/etc/something.conf
> would probably be fine. Installing /opt/local/bin/something would be
> bad, but a database server installed with MacPorts that modifies the
> contents of /opt/local/var/db/something/ while it runs would be ok.

What functionality would this enable? We don't maintain a permanent
local history of archives or the registry. We don't maintain old
versions of the ports tarballs. We keep old binary archives on
packages.macports.org, but that wouldn't help users who don't install
from binaries. I don't think we can implement snapshot functionality
without abusing the word "snapshot". Frankly, anyone who wants the
ability to roll their installation back to a previous state should start
making incremental backups.

I suppose we could merely maintain a log of changes, which might be
helpful when a user suspects their installation has been tampered with.

vq