When installing a fresh NixOS system it occasionally happens that you
encounter issues that are rather hard to track down since
`nixos-install(8)` doesn't provide any debugging flags.
This patch adds `-L` to force `nix build` to display the build-log on
stderr and `-v` to increase the log-level of Nix.
1. This makes aggregates of submodules (including the very important
"nixos-option users.users.<username>" case) behave the same way as any
other you-need-to-keep-typing-to-get-to-an-option-leaf (eg:
"nixos-option environment").
Before e0780c5:
$ nixos-option users.users.root
error: At 'root' in path 'users.users.root': Attribute not found
An error occurred while looking for attribute names. Are you sure that 'users.users.root' exists?
After e0780c5 but before this change, this query just printed out a raw
thing, which is behavior that belongs in "nix eval", "nix-instantiate
--eval", or "nix repl <<<":
$ nixos-option users.users.root
{
_module = {
args = { name = "root"; };
check = true;
};
createHome = false;
cryptHomeLuks = null;
description = "System administrator";
...
After this change:
$ nixos-option users.users.root
This attribute set contains:
createHome
cryptHomeLuks
description
extraGroups
group
hashedPassword
...
2. For aggregates of other types (not submodules), print out the option
that contains them rather than printing an error message.
Before:
$ nixos-option environment.shellAliases.l
error: At 'l' in path 'environment.shellAliases.l': Attribute not found
An error occurred while looking for attribute names. Are you sure that 'environment.shellAliases.l' exists?
After:
$ nixos-option environment.shellAliases.l
Note: showing environment.shellAliases instead of environment.shellAliases.l
Value:
{
l = "ls -alh";
ll = "ls -l";
ls = "ls --color=tty";
}
...
When running e.g. `nixos-option users.users.ma27`, the evaluation breaks
since `ma27` is the attribute name in `attrsOf (submodule {})`, but not
a part of the option tree and therefore breaks with the following
errors:
```
error: At 'ma27' in path 'users.users.ma27': Attribute not found
An error occurred while looking for attribute names. Are you sure that 'users.users.ma27' exists?
```
This happens since the option evaluator expects that either the option
exists or the option is a submodule and the "next" token in the
attribute path points to an option (e.g. `users.users.ma27.createHome`).
This patch checks in the `Attribute not found` condition if the attribute-path
actually exists in the config tree. If that's true, a dummy-attrset is created
which contains `{_type = "__nixos-option-submodule-attr";}`, in that case, the
entire entry of the submodule will be displayed.
Add --use-remote-sudo option. When set, remote commands will be prefixed
with 'sudo'. This allows using sudo remotely _without_ having to use
sudo locally (when using --build-host/--taget-host).
Automated consumers can use 'sed 1d' or similar to remove this header.
This probably makes this output *easier* to consume correctly. Having
this header show up in consumers' terminal or log output is probably not
useful, but hiding it without hiding all error messages would have been
more troublesome that just stripping it from stdout.
I.e., previously, unsophisticated use would show undesired output:
$ some-other-tool
This attribute set contains:
This attribute set contains:
This attribute set contains:
This attribute set contains:
<Actual some-other-tool output>
The simplest way to hide this undesired output would have been
nixos-option ... 2>/dev/null, which would hide all error messages.
We do not wish to encourage that.
Correct use would have been something like:
nixos-option ... 2> >( grep --line-buffered -v 'This attribute set contains:')
After this change, correct use is simpler:
nixos-option ... | sed 1d
or
nixos-option ... | sed '1/This attribute set contains:/d'
if the caller don't know if this invocation of nixos-option will yield
an attribute listing or an option description.
Switch from convention "appease clang-tidy --checks='*'" to
"References are like non-nullptr pointers". The clang-tidy check
"google-runtime-references" complains about non-const reference
arguments, but this is not a convention used in Nix.
Switch from convention "appease clang-tidy --checks='*'" to
"References are like non-nullptr pointers". The clang-tidy check
"google-runtime-references" complains about non-const reference
arguments, but this is not a convention used in Nix.
Switch from convention "appease clang-tidy --checks='*'" to
"References are like non-nullptr pointers". The clang-tidy check
"google-runtime-references" complains about non-const reference
arguments, but this is not a convention used in Nix.
I don't think this matters. As long as one or the other of these is
a std::string, I get an operator== that looks at content rather than
pointer equality. I picked casting the constant over casting the dynamic
thing in hopes that the compiler would have a better chance at optimizing
away any runtime cost.
Deferring to reviewer.
This is important because this contains some code copied from nix (as an
interim expediency until that functionality can be exported via nix's
API). The license specified here must be compatible with this borrowing.
Select the same license that nix is released under: lgpl2Plus.
Specifically, with
clang-format --style='{ IndentWidth: 4, BreakBeforeBraces: Mozilla, ColumnLimit: 120, PointerAlignment: Middle }'
which was the clang-format invocation that produced the fewest diffs on
the nix source out of ~20 that I tried.
Also add --all, which shows the value of all options. Diffing the --all
output on either side of contemplated changes is a lovely way to better
understand what's going on inside nixos.
This adds support for deploying to remote hosts without being root:
sudo nixos-rebuild --target-host non-root@host
Without this change, only root@host is able to deploy.
The idea is that if the local command is run with sudo, so should the
remote one, thus there is no need for adding any CLI options.
I have `users.defaultUserShell = pkgs.fish;` set on my server and when I ran `nixos-rebuild switch --target-host …`, the command failed with the following error:
fish: Unsupported use of '='. To run 'nix-store' with a modified environment, please use 'env PATH=… nix-store…'
That is because fish requires env to set environment variables for a program. It should also work on other shells.
This sets networking.useDHCP to false and for all interfaces found the
per-interface useDHCP to true. This replicates the current default
behaviour and prepares for the switch to networkd.
Up until now, the output has been the same for swap devices and swap
files:
{ device = "/var/swapfile"; }
Whereas for swap *files* it's easier to manage them declaratively in
configuration.nix:
{ device = "/var/swapfile"; size = 8192; }
(NixOS will create the swapfile, and later resize it, if the size
attribute is changed.)
With the assumption that swap files are specified in configuration.nix,
it's silly to output them to hardware-configuration.nix.
Add "bcache" to boot.initrd.availableKernelModules if a bcache device is
detected.
This fixes a problem I've had one too many times: I install NixOS and
forget to add "bcache", resulting in an unbootable machine (until fixed
with Live CD). Now NixOS will do it for me.
cross-compilation of `btrfs-tools` is broken, and this usually needless dependency of each system closure on `btrfs-tools` prevents cross-compilation of whole system closures
If setting a root password using the `passwd` call in the
`nixos-install` script fails, it should be explained how set it manually
to ensure that nobody gets accidentally locked out of the system.
If our old Nix can’t evaluate the Nixpkgs channel, try the fallback
from the new channel /first/. That way we can upgrade Nix to a newer
version and support breaking changes to Nix (like seen in the upgrade
o Nix 2.0).
This change should be backported to older NixOS versions!
This hasn't been needed for a long time, even when `mutableUsers =
false`. Setting a uid manually is potentially risky since it could
collide with non-declarative user accounts. (We do check for
collisions between declarative accounts.)
Also simplified the argument parsing to write all currently supported
CLI options into a bash array and pass this to `nix-build`.
Also documented `--option` usage in the corresponding manpage.
I've been asked, on numerous occasions, by my students and others, how
to 'sudo' on NixOS.
Of course new users could read up in the manual on how to do that, or we
could make it more accessible for them by simply making it visible in
the default `configuration.nix` file.
Additionally, as raised in [1], replacing `guest` with something more
recognizable could be potentially beneficial to new users. I've
opted for `jane` for now.
[1]: https://github.com/NixOS/nixpkgs/pull/54519#issuecomment-457012223
There are situations where several filesystems reside on a single encrypted LUKS
device (e.g. when using BTRFS subvolumes).
Simply generating a `boot.init.luks.devices.NAME.device` entry for each mounted
filesystem will result in an error later when evaluating the nix expression in
`hardware-configuration.nix`.
Since nix 2.0 the no-build-hook option was replaced by the builders options
that allows to override remote builders ad-hoc.
Since it is useful to disable remote builders updating nixos without network,
this commit reintroduces the option.
This adds a NixOS option for setting the CPU max and min frequencies
with `cpufreq`. The two options that have been added are:
- `powerManagement.cpufreq.max`
- `powerManagement.cpufreq.min`
It also adds an alias to the `powerManagement.cpuFreqGovernor` option as
`powerManagement.cpufreq.governor`. This updates the installer to use
the new option name. It also updates the manual with a note about
the new name.
Previously I got the following error message:
```
error: opening file '/home/ma27/Projects/nixpkgs/nixos/modules/installer/default.nix': No such file or directory
```
Probably related to 6c68fbd4e1.
This reverts commit 10addad603, reversing
changes made to 7786575c6c.
NixOS scripts should be kept in the NixOS source tree, not in
pkgs. Moving them around is just confusing and creates unnecessary
code/history churn.
Move all the nixos-* scripts from the nixos distribution as real
packages in the pkgs/ package set.
This allows non-nixos users to run the script as well. For example,
deploying a remote machine with:
nixos-rebuild --target-host root@hostname --build-host root@hostname
The system variable is used from the (possibly polluted) shell
environment.
This causes nixos-install to fail in a nix-shell because the system
shell variable is automatically set to the current system (e.g.
x86_64-linux).
`nixos-option` basically handles two cases: the given option is either a
valid option defined using `mkOption` or an attribute set which contains
a set of options.
If none of the above cases is valid, `$1` is invalid. Unfortunatley the
script interpreted invalid options as an attribute set which rendered
shell failures when trying to evaluate the arguments.
First of all, `if names=$(attrNames ...)` resulted in `<PRIMOP>` as
`attrNames` simply evaluated `builtins.attrNames $result` which results
in a non-applied function with `$result` being empty. Trying to map over
this string using `nixMap` while applying `escapeQuotes` causes the bash
error as `eval echo "<PRIMOP>"` is invalid syntax.
Explicitly checking if `$result' contains a value (do we have an
attribute set?) and otherwise returning a warning and asking if $option
exists fixes the problem.
Fixes#48060
The problem was that the non-fatal warning was not omitted
from the output when constructing a nix expression.
Now it seems OK for me. When return code is OK,
the warnings don't get passed anywhere, but I expect
that won't matter for this utility. Fatal errors are still shown.
The instructions to install nixos behind a proxy were not clear. While
one could guess that setting http_proxy variables can get the install
rolling, one could end up with an installed system where the proxy
settings for the nix-daemon are not configured.
This commit updates the documentation with
1. steps to install behind a proxy
2. configure the global proxy settings so that nix-daemon can access
internet.
3. Pointers to use nesting.clone in case one has to use different proxy
settings on different networks.
This reverts commit 095fe5b43d.
Pointless renames considered harmful. All they do is force people to
spend extra work updating their configs for no benefit, and hindering
the ability to switch between unstable and stable versions of NixOS.
Like, what was the value of having the "nixos." there? I mean, by
definition anything in a NixOS module has something to do with NixOS...
When running e.g. `nixos-option boot.kernelPackages` I get an output
like this on the current unstable channel (18.09pre144959.be1461fc0ab):
```
$ nixos-option boot.kernelPackages
Value:
*exit 1*
```
This is fairly counter-intuitive as I have no clue what might went
wrong. `strace` delivers an output like this:
```
read(3, "error: Package \342\200\230cryptodev-linu"..., 128) = 128
read(3, "ux/cryptodev/default.nix:22 is m"..., 128) = 128
read(3, "lowBroken = true; }\nin configura"..., 128) = 128
read(3, "you can add\n { allowBroken = tr"..., 128) = 128
read(3, "n)\n", 128) = 3
read(3, "", 128) = 0
```
`nixos-option` evaluates the system config using `nix-instantiate` which
might break when the evaluation fails (e.g. due to broken or unfree
packages that are prohibited to evaluate by default). The script aborts
due to the shebang `@shell@ -e`.
In order to ensure that no unexpected
behavior occurs due to removing `-e` from the interpreter the easiest
way to work around this was to wrap `nix-instantiate` in `evalNix()`
with a `set +e`. The function checks the success of the evaluation with
`$?` in the end. Additionally `evalNix` shouldn't break, if one
evaluation (e.g. the values that contain a package set by default) to
return additional information like a description.
With the change `nixos-option boot.kernelPackages` delivers the
following output for me:
```
Value:
error: Package ‘cryptodev-linux-1.9-4.14.52’ in /nix/store/47z2s8cwppymmgzw6n7pbcashikyk5jk-nixos/nixos/pkgs/os-specific/linux/cryptodev/default.nix:22 is marked as broken, refusing to evaluate.
Default:
{ __unfix__ = <LAMBDA>; acpi_call = <CODE>; amdgpu-pro = <CODE>; ati_drivers_x11 = <CODE>; batman_adv = <CODE>; bbswitch = <CODE>; bcc = <CODE>; beegfs-module = <CODE>; blcr = <CODE>; broadcom_sta = <CODE>; callPackage = <CODE>; cpupower = <CODE>; cryptodev = <CODE>; dpdk = <CODE>; e1000e = <CODE>; ena = <CODE>; evdi = <CODE>; exfat-nofuse = <CODE>; extend = <CODE>; facetimehd = <CODE>; fusionio-vsl = <CODE>; hyperv-daemons = <CODE>; ixgbevf = <CODE>; jool = <CODE>; kernel = <CODE>; lttng-modules = <CODE>; mba6x_bl = <CODE>; mwprocapture = <CODE>; mxu11x0 = <CODE>; ndiswrapper = <CODE>; netatop = <CODE>; nvidiaPackages = <CODE>; nvidia_x11 = <CODE>; nvidia_x11_beta = <CODE>; nvidia_x11_legacy304 = <CODE>; nvidia_x11_legacy340 = <CODE>; nvidiabl = <CODE>; odp-dpdk = <CODE>; openafs = <CODE>; openafs_1_8 = <CODE>; perf = <CODE>; phc-intel = <CODE>; pktgen = <CODE>; ply = <CODE>; prl-tools = <CODE>; recurseForDerivations = true; rtl8192eu = <CODE>; rtl8723bs = <CODE>; rtl8812au = <CODE>; rtl8814au = <CODE>; rtlwifi_new = <CODE>; sch_cake = <CODE>; spl = <CODE>; splLegacyCrypto = <CODE>; splStable = <CODE>; splUnstable = <CODE>; stdenv = <CODE>; sysdig = <CODE>; systemtap = <CODE>; tbs = <CODE>; tmon = <CODE>; tp_smapi = <CODE>; usbip = <CODE>; v4l2loopback = <CODE>; v86d = <CODE>; vhba = <CODE>; virtualbox = <CODE>; virtualboxGuestAdditions = <CODE>; wireguard = <CODE>; x86_energy_perf_policy = <CODE>; zfs = <CODE>; zfsLegacyCrypto = <CODE>; zfsStable = <CODE>; zfsUnstable = <CODE>; }
Example:
{ _type = "literalExample"; text = "pkgs.linuxPackages_2_6_25"; }
Description:
"This option allows you to override the Linux kernel used by\nNixOS. Since things like external kernel module packages are\ntied to the kernel you're using, it also overrides those.\nThis option is a function that takes Nixpkgs as an argument\n(as a convenience), and returns an attribute set containing at\nthe very least an attribute <varname>kernel</varname>.\nAdditional attributes may be needed depending on your\nconfiguration. For instance, if you use the NVIDIA X driver,\nthen it also needs to contain an attribute\n<varname>nvidia_x11</varname>.\n"
Declared by:
"/nix/var/nix/profiles/per-user/root/channels/nixos/nixpkgs/nixos/modules/system/boot/kernel.nix"
Defined by:
"/home/ma27/Projects/nixos-config/system/boot.nix"
```
This partially reverts a change from e88f28965a
which removed the `mount --rbind /sys`.
While true that the activation scripts will mount `sysfs` at `/sys`,
none of the mountpoints lower in the `/sys` tree are handled by the
activation script, which includes `efivarfs`.
This fixes#38477 since it ensures the presence of `efivarfs` in the
`/sys` tree, which is why the systemd-boot installation failed.
Because it improves out-of-the-box user experience a lot (IMHO).
(zsh completion is already on by default.)
Remove "programs.bash.enableCompletion = true" from
nixos-generate-config.pl, which feels superflous now.
Of course, you'll get a bunch of warnings from the activation script:
$ nixos-enter --root /tmp/mnt/
setting up /etc...
mount: /dev: permission denied.
mount: /dev/pts: permission denied.
mount: /dev/shm: permission denied.
mount: /sys: permission denied.
/nix/var/nix/profiles/system/activate: line 74: /proc/sys/kernel/modprobe: Permission denied
chown: changing ownership of '/run/wrappers/wrappers.0pKlU8JsvV/dbus-daemon-launch-helper': Invalid argument
NOTE: Under Linux, effective file capabilities must either be empty, or
exactly match the union of selected permitted and inheritable bits.
Failed to set capabilities on file `/run/wrappers/wrappers.0pKlU8JsvV/ping' (Operation not permitted)
chown: changing ownership of '/run/wrappers/wrappers.0pKlU8JsvV/unix_chkpwd': Invalid argument
[root@nixos:/]#
The use of Nix 2.0 significantly simplifies the installer, since we
can just pass a different store URI (--store /mnt) - it's no longer
needed to set up a chroot environment for the build, and to bootstrap
Nix into the chroot.
Also, commands that need to run in the installation (namely boot
loader installation and setting a root password) are now executed
using nixos-enter.
This also removes the need for nixos-prepare-root since any required
initialisation is done by Nix or by the activation script.
In particular, it conflicts with `services.tlp.enable` option.
There exists workaround:
```
powerManagement.cpuFreqGovernor = lib.mkForce null;
services.tlp.enable = true;
```
But should it?
Regression introduced by 801c920e95.
Since then, the btrfsSimple subtest of the installer VM test fails with:
Btrfs did not return a path for the subvolume at /
The reason for this is that the output for "btrfs subvol show" has
changed between version 4.8.2 and 4.13.1.
For example the output of "btrfs subvol show /" in version 4.8.2 was:
/ is toplevel subvolume
In version 4.13.1, the output now is the following and thus the regular
expressions used in nixos-generate-config.pl and install-grub.pl now
match (which results in the error mentioned above):
/
Name: <FS_TREE>
UUID: -
Parent UUID: -
Received UUID: -
Creation time: -
Subvolume ID: 5
Generation: 287270
Gen at creation: 0
Parent ID: 0
Top level ID: 0
Flags: -
Snapshot(s):
In order to fix this I've changed nixos-generate-config.pl and
install-grub.pl, because both use "btrfs subvol show" in a similar vein,
so the regex for parsing the output now doesn't match anymore whenever
the volume path is "/", which should result in the same behaviour as we
had with btrfs-progs version 4.8.2.
Tested against the btrfsSimple, btrfsSubvols and btrfsSubvolDefault
subtests of the installer VM test and they all succeed now.
Signed-off-by: aszlig <aszlig@redmoonstudios.org>
This changes much of the make-disk-image.nix logic (and thus most NixOS
image building) to use LKL to set up the target directory structure rather
than a Linux VM. The only work we still do in a VM is less IO-heavy stuff
that while still time-consuming, is less of the overall load. The goal is
to kill more of that stuff, but that will require deeper changes to NixOS
activation scripts and switch-to-configuration.pl, and I don't want to
bite off too much at once.
The key distinction I'm drawing is that there's a component that deals
with the store of the machine being built, and another component for
the store building it. The inner part of it assumes nothing from the
builder (doesn't need chroot or root powers) so it can run comfortably
inside a Nix build, as well as nixos-rebuild. I have some upcoming work
that will use that to significantly speed up and streamline image builds
for NixOS, especially on virtualized hosts like EC2, but it's also a
reasonable speedup on native hosts.
* cpu-freq: Try powersave if ondemand is not available
* Revert "cpu-freq: Try powersave if ondemand is not available"
This reverts commit 4dc56db37e32dcfecd667ebbf88263e47b296097.
Consult available scaling governors; for freshly generated configs, this provides a better experience than relying on a default that might not work everywhere.
`startAt = ""` as in `startAt = optionalString false ...` results
in an invalid timer unit (due to "" being promoted to a singleton
list and not filtered out).
Ref: c9941c4b5e
Since some changes to the setuid wrappers, there is a symlink involved
and it doesn't resolve correctly inside the chroot. Do the check inside
the chroot to make it work again.
This partially reverts commit 0aa7520670.
Fine for rsync to be in system path but we still need the explicit path
in nixos-install in case it is invoked from non-NixOS systems and also
to fix OVA test failure
See also 0aa7520670
cc @edolstra
This reverts commit 582313bafe.
Removing rsync is actually pointless because nixos-install depends on
it. So if it's part of the system closure, we may as well provide it
to users.
Probably with the next Nix release we can drop the use of rsync and
use "nix copy" instead.
Before this commit updating /var/setuid-wrappers/ folder introduced
a small window where NixOS activation scripts could be terminated
and resulted into empty /var/setuid-wrappers/ folder.
That's very unfortunate because one might lose sudo binary.
Instead we use two atomic operations mv and ln (as described in
https://axialcorps.com/2013/07/03/atomically-replacing-files-and-directories/)
to achieve atomicity.
Since /var/setuid-wrappers is not a directory anymore, tmpfs mountpoints
were removed in installation scripts and in boot process.
Tested:
- upgrade /var/setuid-wrappers/ from folder to a symlink
- make sure /run/setuid-wrappers-dirs/ legacy symlink is really deleted
- Replace hand-rolled version of nixos-install in make-disk-image by an
actual call to nixos-install
- Required a few cleanups of nixos-install
- nixos-install invokes an activation script which the hand-rolled version
in make-disk-image did not do. We remove /etc/machine-id as that's
a host-specific, impure, output of the activation script
Testing:
nix-build '<nixpkgs/nixos/release.nix>' -A tests.installer.simple passes
Also tried generating an image with:
nix-build -E 'let
pkgs = import <nixpkgs> {};
lib = pkgs.lib;
nixos = import <nixpkgs/nixos> {
configuration = {
fileSystems."/".device = "/dev/disk/by-label/nixos";
boot.loader.grub.devices = [ "/dev/sda" ];
boot.loader.grub.extraEntries = '"''"'
menuentry "Ubuntu" {
insmod ext2
search --set=root --label ubuntu
configfile /boot/grub/grub.cfg
}
'"''"';
};
};
in import <nixpkgs/nixos/lib/make-disk-image.nix> {
inherit pkgs lib;
config = nixos.config;
diskSize = 2000;
partitioned = false;
installBootLoader = false;
}'
Then installed the image:
$ sudo df if=./result/nixos.img of=/dev/sdaX bs=1M
$ sudo resize2fs /dev/disk/by-label/nixos
$ sudo mount /dev/disk/by-label/nixos /mnt
$ sudo mount --rbind /proc /mnt/proc
$ sudo mount --rbind /dev /mnt/dev
$ sudo chroot /mnt /nix/var/nix/profiles/system/bin/switch-to-configuration boot
[ … optionally do something about passwords … ]
and successfully rebooted to that image.
Was doing all this from inside a Ubuntu VM with a single user nix install.
- Fix --no-bootloader which didn't do what it advertised
- Hardcode nixbld GID so that systems which do not have a nixbld user
can still run nixos-install (only with --closure since they can't
build anything)
- Cleanup: get rid of NIX_CONF_DIR(=/tmp)/nix.conf and pass arguments instead
- Cleanup: don't assume that the target system has '<nixpkgs/nixos>' or
'<nixos-config>' to see if config.users.mutableUsers. Instead check if
/var/setuid-wrappers/passwd is there
Installing NixOS now works from a Ubuntu host (using --closure).
nix-build -A tests.installer.simple '<nixpkgs/nixos/release.nix>' succeeds ✓
This reverts commit 1e534e234b.
We already should have a .git directory if it is managed via Git,
otherwise there is no way to get the Git revision if neither
.git-revision or .git is present.
But having .git-revision _and_ .git present seems very much redundant to
me.
Signed-off-by: aszlig <aszlig@redmoonstudios.org>
Cc: @bennofs, @Profpatsch
Issue: #17218
This command was useful when NixOS was spread across multiple
repositories, but now it's pretty pointless (and obfuscates what
happens, i.e. "git clone git://github.com/NixOS/nixpkgs.git").
- Enforce that an option declaration has a "defaultText" if and only if the
type of the option derives from "package", "packageSet" or "nixpkgsConfig"
and if a "default" attribute is defined.
- Enforce that the value of the "example" attribute is wrapped with "literalExample"
if the type of the option derives from "package", "packageSet" or "nixpkgsConfig".
- Warn if a "defaultText" is defined in an option declaration if the type of
the option does not derive from "package", "packageSet" or "nixpkgsConfig".
- Warn if no "type" is defined in an option declaration.
Allow usage of list of strings instead of a comma-separated string
for filesystem options. Deprecate the comma-separated string style
with a warning message; convert this to a hard error after 16.09.
15.09 was just released, so this provides a deprecation period during
the 16.03 release.
closes#10518
Signed-off-by: Robin Gloster <mail@glob.in>
