The CrOS SDK chroot includes a series of bash hooks that modify INSTALL_MASK for some packages. However, it seems we don't set up INSTALL_MASK properly on devices, so 'cros deploy' fails with file collisions. For example, try running 'cros deploy ... net-dns/avahi', and you will see failures like the following:


$ cros deploy --board=${BOARD} $IP avahi
11:14:53: NOTICE: Cleaning outdated binary packages from /build/samus
11:14:59: NOTICE: These are the packages to emerge:
11:14:59: NOTICE: * 1) net-dns/avahi-0.6.31-r4
 [##############################################################################################################-------------------] 85%Exception during output capturing: RunCommandError("cwd=None, extra env={'LC_MESSAGES': 'C'}", <chromite.lib.cros_build_lib.CommandResult object at 0x7fa608add150>, None)
Captured stdout was:
sending incremental file list
avahi-0.6.31-r4.tbz2

sent 244,671 bytes  received 35 bytes  163,137.33 bytes/sec
total size is 251,169  speedup is 1.03

*** emerging by path is broken and may not always work!!!

Calculating dependencies  ... done!

>>> Emerging binary (1 of 1) net-dns/avahi-0.6.31-r4::portage-stable
 * avahi-0.6.31-r4.tbz2 size ;-) ...                                     [ ok ]
>>> Extracting info
 * Running stacked hooks for pre_pkg_setup
 *    sysroot_build_bin_dir ...
 [ ok ]
>>> Extracting net-dns/avahi-0.6.31-r4

>>> Installing (1 of 1) net-dns/avahi-0.6.31-r4::portage-stable
 * This package will overwrite one or more files that may belong to other
 * packages (see list below). You can use a command such as `portageq
 * owners / <filename>` to identify the installed package that owns a
 * file. If portageq reports that only one package owns a file then do
 * NOT file a bug report. A bug report is only useful if it identifies at
 * least two or more packages that are known to install the same file(s).
 * If a collision occurs and you can not explain where the file came from
 * then you should simply ignore the collision since there is not enough
 * information to determine if a real problem exists. Please do NOT file
 * a bug report at http://bugs.gentoo.org unless you report exactly which
 * two packages install the same file(s). See
 * http://wiki.gentoo.org/wiki/Knowledge_Base:Blockers for tips on how to
 * solve the problem. And once again, please do NOT file a bug report
 * unless you have completely understood the above message.
 * 
 * Detected file collision(s):
 * 
 * 	/etc/avahi/avahi-daemon.conf
 * 
 * Searching all installed packages for file collisions...
 * 
 * Press Ctrl-C to Stop
 * 
 * chromeos-base/chromeos-base-0-r132:0::chromiumos
 * 	/etc/avahi/avahi-daemon.conf
 * 
 * Package 'net-dns/avahi-0.6.31-r4' NOT merged due to file collisions.
 * If necessary, refer to your elog messages for the whole content of the
 * above message.

>>> Failed to install net-dns/avahi-0.6.31-r4, Log file:
[...]