qemu.inc: Use '=' for IMAGE_FSTYPES

Submitted by Tom Rini on March 23, 2012, 5:35 p.m.

Details

Message ID 1332524132-24689-1-git-send-email-trini@ti.com
State New
Headers show

Commit Message

Tom Rini March 23, 2012, 5:35 p.m.
As per
http://lists.linuxtogo.org/pipermail/openembedded-core/2012-March/019772.html
a machine conf file should use '=' to set IMAGE_FSTYPES.

Signed-off-by: Tom Rini <trini@ti.com>
---
 meta/conf/machine/include/qemu.inc |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

Patch hide | download patch | download mbox

diff --git a/meta/conf/machine/include/qemu.inc b/meta/conf/machine/include/qemu.inc
index 10ab76e..b613287 100644
--- a/meta/conf/machine/include/qemu.inc
+++ b/meta/conf/machine/include/qemu.inc
@@ -3,7 +3,7 @@  PREFERRED_PROVIDER_virtual/xserver ?= "xserver-kdrive"
 
 MACHINE_FEATURES = "apm alsa pcmcia bluetooth irda usbgadget screen"
 
-IMAGE_FSTYPES ?= "tar.bz2 ext3"
+IMAGE_FSTYPES = "tar.bz2 ext3"
 
 ROOT_FLASH_SIZE = "280"
 

Comments

Richard Purdie March 26, 2012, 9:15 a.m.
On Fri, 2012-03-23 at 10:35 -0700, Tom Rini wrote:
> As per
> http://lists.linuxtogo.org/pipermail/openembedded-core/2012-March/019772.html
> a machine conf file should use '=' to set IMAGE_FSTYPES.
> 
> Signed-off-by: Tom Rini <trini@ti.com>
> ---
>  meta/conf/machine/include/qemu.inc |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)

As someone pointed out, what I mentioned in that email sadly doesn't
work although it would be nice if they did. I suspect this is why we're
using += since:

> - The machine needs to say 'I need or support the following formats'

so the machine ensures those formats exist at a minimum:

IMAGE_FSTYPES += "xxxx"

> - The distro needs to say 'I always want format X'

so the distro can do:

IMAGE_FSTYPES += " yyy"

> - The user needs to say 'I know best, give me only format X'

This one is the problem case so the user has to use overrides:

IMAGE_FSTYPES_override = "X"

(where override can be MACHINE or forcevariable)

> - The user needs to say 'I know best, give me what you support + X'

IMAGE_FSTYPES += " X"


Whilst I think that is less than ideal since it forces use of overrides
in local.conf to override, changing the += in machine conf files doesn't
gain us much, it just breaks += in local.conf.

I'm open to other feedback though...

Cheers,

Richard
Tom Rini March 26, 2012, 4:25 p.m.
On Mon, Mar 26, 2012 at 10:15:13AM +0100, Richard Purdie wrote:
> On Fri, 2012-03-23 at 10:35 -0700, Tom Rini wrote:
> > As per
> > http://lists.linuxtogo.org/pipermail/openembedded-core/2012-March/019772.html
> > a machine conf file should use '=' to set IMAGE_FSTYPES.
> > 
> > Signed-off-by: Tom Rini <trini@ti.com>
> > ---
> >  meta/conf/machine/include/qemu.inc |    2 +-
> >  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> As someone pointed out, what I mentioned in that email sadly doesn't
> work although it would be nice if they did. I suspect this is why we're
> using += since:

We aren't using += today.  We (openembedded-core) use ?=.  meta-intel
uses += and meta-ti is mixed (and I don't have meta-fsl-* handy).

> > - The machine needs to say 'I need or support the following formats'
> 
> so the machine ensures those formats exist at a minimum:
> 
> IMAGE_FSTYPES += "xxxx"
> 
> > - The distro needs to say 'I always want format X'
> 
> so the distro can do:
> 
> IMAGE_FSTYPES += " yyy"
> 
> > - The user needs to say 'I know best, give me only format X'
> 
> This one is the problem case so the user has to use overrides:
> 
> IMAGE_FSTYPES_override = "X"
> 
> (where override can be MACHINE or forcevariable)
> 
> > - The user needs to say 'I know best, give me what you support + X'
> 
> IMAGE_FSTYPES += " X"
> 
> 
> Whilst I think that is less than ideal since it forces use of overrides
> in local.conf to override, changing the += in machine conf files doesn't
> gain us much, it just breaks += in local.conf.
> 
> I'm open to other feedback though...

Well, I suggested ??= / ?= and posted some results from bitbake -e...
Richard Purdie March 26, 2012, 4:56 p.m.
On Mon, 2012-03-26 at 09:25 -0700, Tom Rini wrote:
> On Mon, Mar 26, 2012 at 10:15:13AM +0100, Richard Purdie wrote:
> > On Fri, 2012-03-23 at 10:35 -0700, Tom Rini wrote:
> > > As per
> > > http://lists.linuxtogo.org/pipermail/openembedded-core/2012-March/019772.html
> > > a machine conf file should use '=' to set IMAGE_FSTYPES.
> > > 
> > > Signed-off-by: Tom Rini <trini@ti.com>
> > > ---
> > >  meta/conf/machine/include/qemu.inc |    2 +-
> > >  1 files changed, 1 insertions(+), 1 deletions(-)
> > 
> > As someone pointed out, what I mentioned in that email sadly doesn't
> > work although it would be nice if they did. I suspect this is why we're
> > using += since:
> 
> We aren't using += today.  We (openembedded-core) use ?=.  meta-intel
> uses += and meta-ti is mixed (and I don't have meta-fsl-* handy).
> 
> > > - The machine needs to say 'I need or support the following formats'
> > 
> > so the machine ensures those formats exist at a minimum:
> > 
> > IMAGE_FSTYPES += "xxxx"
> > 
> > > - The distro needs to say 'I always want format X'
> > 
> > so the distro can do:
> > 
> > IMAGE_FSTYPES += " yyy"
> > 
> > > - The user needs to say 'I know best, give me only format X'
> > 
> > This one is the problem case so the user has to use overrides:
> > 
> > IMAGE_FSTYPES_override = "X"
> > 
> > (where override can be MACHINE or forcevariable)
> > 
> > > - The user needs to say 'I know best, give me what you support + X'
> > 
> > IMAGE_FSTYPES += " X"
> > 
> > 
> > Whilst I think that is less than ideal since it forces use of overrides
> > in local.conf to override, changing the += in machine conf files doesn't
> > gain us much, it just breaks += in local.conf.
> > 
> > I'm open to other feedback though...
> 
> Well, I suggested ??= / ?= and posted some results from bitbake -e...

Ok. += plays out as above. I realise its not what is in qemu.inc, it is
used in meta-intel though which I looked at after qemu.inc and I guess
has confused me.

With ?= in machine.conf:

The user defined IMAGE_FSTYPES would override the machine ones. Distro
can still append to it. The downside is a user append would not work out
as expected.

So the question is which is the more user expected behaviour?

=+ makes overwriting IMAGE_FSTYPES hard

?= makes appending IMAGE_FSTYPES hard

I suspect a user is more likely to want to append than overwrite.
Getting an append to work with ?= is extremely non-obvious, even worse
syntax than the =+ overwriting case with overrides.

So bottom line, I'm tempted to recommend we use =+.

Further thoughts?

Cheers,

Richard
Tom Rini March 26, 2012, 5:13 p.m.
On Mon, Mar 26, 2012 at 05:56:16PM +0100, Richard Purdie wrote:
> On Mon, 2012-03-26 at 09:25 -0700, Tom Rini wrote:
> > On Mon, Mar 26, 2012 at 10:15:13AM +0100, Richard Purdie wrote:
> > > On Fri, 2012-03-23 at 10:35 -0700, Tom Rini wrote:
> > > > As per
> > > > http://lists.linuxtogo.org/pipermail/openembedded-core/2012-March/019772.html
> > > > a machine conf file should use '=' to set IMAGE_FSTYPES.
> > > > 
> > > > Signed-off-by: Tom Rini <trini@ti.com>
> > > > ---
> > > >  meta/conf/machine/include/qemu.inc |    2 +-
> > > >  1 files changed, 1 insertions(+), 1 deletions(-)
> > > 
> > > As someone pointed out, what I mentioned in that email sadly doesn't
> > > work although it would be nice if they did. I suspect this is why we're
> > > using += since:
> > 
> > We aren't using += today.  We (openembedded-core) use ?=.  meta-intel
> > uses += and meta-ti is mixed (and I don't have meta-fsl-* handy).
> > 
> > > > - The machine needs to say 'I need or support the following formats'
> > > 
> > > so the machine ensures those formats exist at a minimum:
> > > 
> > > IMAGE_FSTYPES += "xxxx"
> > > 
> > > > - The distro needs to say 'I always want format X'
> > > 
> > > so the distro can do:
> > > 
> > > IMAGE_FSTYPES += " yyy"
> > > 
> > > > - The user needs to say 'I know best, give me only format X'
> > > 
> > > This one is the problem case so the user has to use overrides:
> > > 
> > > IMAGE_FSTYPES_override = "X"
> > > 
> > > (where override can be MACHINE or forcevariable)
> > > 
> > > > - The user needs to say 'I know best, give me what you support + X'
> > > 
> > > IMAGE_FSTYPES += " X"
> > > 
> > > 
> > > Whilst I think that is less than ideal since it forces use of overrides
> > > in local.conf to override, changing the += in machine conf files doesn't
> > > gain us much, it just breaks += in local.conf.
> > > 
> > > I'm open to other feedback though...
> > 
> > Well, I suggested ??= / ?= and posted some results from bitbake -e...
> 
> Ok. += plays out as above. I realise its not what is in qemu.inc, it is
> used in meta-intel though which I looked at after qemu.inc and I guess
> has confused me.
> 
> With ?= in machine.conf:
> 
> The user defined IMAGE_FSTYPES would override the machine ones. Distro
> can still append to it. The downside is a user append would not work out
> as expected.
> 
> So the question is which is the more user expected behaviour?
> 
> =+ makes overwriting IMAGE_FSTYPES hard
> 
> ?= makes appending IMAGE_FSTYPES hard
> 
> I suspect a user is more likely to want to append than overwrite.
> Getting an append to work with ?= is extremely non-obvious, even worse
> syntax than the =+ overwriting case with overrides.
> 
> So bottom line, I'm tempted to recommend we use =+.

I think for the upcoming release, =+ is good enough and we can talk
about adding further variables after if it's still too complicated.  So,
now where's the repo that documenting these examples should go in?
Darren Hart March 26, 2012, 6:39 p.m.
On 03/26/2012 10:13 AM, Tom Rini wrote:

> 
> I think for the upcoming release, =+ is good enough and we can talk
> about adding further variables after if it's still too complicated.  So,
> now where's the repo that documenting these examples should go in?
> 

You want to talk to Scott Rifenbark, on CC.
Denys Dmytriyenko March 26, 2012, 7:31 p.m.
On Mon, Mar 26, 2012 at 10:13:59AM -0700, Tom Rini wrote:
> On Mon, Mar 26, 2012 at 05:56:16PM +0100, Richard Purdie wrote:
> > On Mon, 2012-03-26 at 09:25 -0700, Tom Rini wrote:
> > > On Mon, Mar 26, 2012 at 10:15:13AM +0100, Richard Purdie wrote:
> > > > On Fri, 2012-03-23 at 10:35 -0700, Tom Rini wrote:
> > > > > As per
> > > > > http://lists.linuxtogo.org/pipermail/openembedded-core/2012-March/019772.html
> > > > > a machine conf file should use '=' to set IMAGE_FSTYPES.
> > > > > 
> > > > > Signed-off-by: Tom Rini <trini@ti.com>
> > > > > ---
> > > > >  meta/conf/machine/include/qemu.inc |    2 +-
> > > > >  1 files changed, 1 insertions(+), 1 deletions(-)
> > > > 
> > > > As someone pointed out, what I mentioned in that email sadly doesn't
> > > > work although it would be nice if they did. I suspect this is why we're
> > > > using += since:
> > > 
> > > We aren't using += today.  We (openembedded-core) use ?=.  meta-intel
> > > uses += and meta-ti is mixed (and I don't have meta-fsl-* handy).
> > > 
> > > > > - The machine needs to say 'I need or support the following formats'
> > > > 
> > > > so the machine ensures those formats exist at a minimum:
> > > > 
> > > > IMAGE_FSTYPES += "xxxx"
> > > > 
> > > > > - The distro needs to say 'I always want format X'
> > > > 
> > > > so the distro can do:
> > > > 
> > > > IMAGE_FSTYPES += " yyy"
> > > > 
> > > > > - The user needs to say 'I know best, give me only format X'
> > > > 
> > > > This one is the problem case so the user has to use overrides:
> > > > 
> > > > IMAGE_FSTYPES_override = "X"
> > > > 
> > > > (where override can be MACHINE or forcevariable)
> > > > 
> > > > > - The user needs to say 'I know best, give me what you support + X'
> > > > 
> > > > IMAGE_FSTYPES += " X"
> > > > 
> > > > 
> > > > Whilst I think that is less than ideal since it forces use of overrides
> > > > in local.conf to override, changing the += in machine conf files doesn't
> > > > gain us much, it just breaks += in local.conf.
> > > > 
> > > > I'm open to other feedback though...
> > > 
> > > Well, I suggested ??= / ?= and posted some results from bitbake -e...
> > 
> > Ok. += plays out as above. I realise its not what is in qemu.inc, it is
> > used in meta-intel though which I looked at after qemu.inc and I guess
> > has confused me.
> > 
> > With ?= in machine.conf:
> > 
> > The user defined IMAGE_FSTYPES would override the machine ones. Distro
> > can still append to it. The downside is a user append would not work out
> > as expected.
> > 
> > So the question is which is the more user expected behaviour?
> > 
> > =+ makes overwriting IMAGE_FSTYPES hard
> > 
> > ?= makes appending IMAGE_FSTYPES hard
> > 
> > I suspect a user is more likely to want to append than overwrite.
> > Getting an append to work with ?= is extremely non-obvious, even worse
> > syntax than the =+ overwriting case with overrides.
> > 
> > So bottom line, I'm tempted to recommend we use =+.
> 
> I think for the upcoming release, =+ is good enough and we can talk
> about adding further variables after if it's still too complicated.  So,
> now where's the repo that documenting these examples should go in?

So, did we come full circle on this? :) Started here:
https://lists.yoctoproject.org/pipermail/meta-ti/2012-March/000779.html

I'm fine changing it for meta-ti, if we agree on a unified solution. Having an 
EXTRA/MACHINE var for that in the future might simplify things...
Denys Dmytriyenko March 28, 2012, 6:54 p.m.
On Mon, Mar 26, 2012 at 05:56:16PM +0100, Richard Purdie wrote:
> On Mon, 2012-03-26 at 09:25 -0700, Tom Rini wrote:
> > On Mon, Mar 26, 2012 at 10:15:13AM +0100, Richard Purdie wrote:
> > > On Fri, 2012-03-23 at 10:35 -0700, Tom Rini wrote:
> > > > As per
> > > > http://lists.linuxtogo.org/pipermail/openembedded-core/2012-March/019772.html
> > > > a machine conf file should use '=' to set IMAGE_FSTYPES.
> > > > 
> > > > Signed-off-by: Tom Rini <trini@ti.com>
> > > > ---
> > > >  meta/conf/machine/include/qemu.inc |    2 +-
> > > >  1 files changed, 1 insertions(+), 1 deletions(-)
> > > 
> > > As someone pointed out, what I mentioned in that email sadly doesn't
> > > work although it would be nice if they did. I suspect this is why we're
> > > using += since:
> > 
> > We aren't using += today.  We (openembedded-core) use ?=.  meta-intel
> > uses += and meta-ti is mixed (and I don't have meta-fsl-* handy).
> > 
> > > > - The machine needs to say 'I need or support the following formats'
> > > 
> > > so the machine ensures those formats exist at a minimum:
> > > 
> > > IMAGE_FSTYPES += "xxxx"
> > > 
> > > > - The distro needs to say 'I always want format X'
> > > 
> > > so the distro can do:
> > > 
> > > IMAGE_FSTYPES += " yyy"
> > > 
> > > > - The user needs to say 'I know best, give me only format X'
> > > 
> > > This one is the problem case so the user has to use overrides:
> > > 
> > > IMAGE_FSTYPES_override = "X"
> > > 
> > > (where override can be MACHINE or forcevariable)
> > > 
> > > > - The user needs to say 'I know best, give me what you support + X'
> > > 
> > > IMAGE_FSTYPES += " X"
> > > 
> > > 
> > > Whilst I think that is less than ideal since it forces use of overrides
> > > in local.conf to override, changing the += in machine conf files doesn't
> > > gain us much, it just breaks += in local.conf.
> > > 
> > > I'm open to other feedback though...
> > 
> > Well, I suggested ??= / ?= and posted some results from bitbake -e...
> 
> Ok. += plays out as above. I realise its not what is in qemu.inc, it is
> used in meta-intel though which I looked at after qemu.inc and I guess
> has confused me.
> 
> With ?= in machine.conf:
> 
> The user defined IMAGE_FSTYPES would override the machine ones. Distro
> can still append to it. The downside is a user append would not work out
> as expected.
> 
> So the question is which is the more user expected behaviour?
> 
> =+ makes overwriting IMAGE_FSTYPES hard
> 
> ?= makes appending IMAGE_FSTYPES hard
> 
> I suspect a user is more likely to want to append than overwrite.
> Getting an append to work with ?= is extremely non-obvious, even worse
> syntax than the =+ overwriting case with overrides.
> 
> So bottom line, I'm tempted to recommend we use =+.
> 
> Further thoughts?

Richard,

So, what is the subtle difference between += that we started with and =+ that 
you recommended at the end? I realize those are for append and prepend, but 
are they handled any different? Was your recommendation to use =+ at the end, 
instead of += that was used originally, based on some specifics? Thanks.
Richard Purdie March 28, 2012, 9:11 p.m.
On Wed, 2012-03-28 at 14:54 -0400, Denys Dmytriyenko wrote:
> On Mon, Mar 26, 2012 at 05:56:16PM +0100, Richard Purdie wrote:
> > On Mon, 2012-03-26 at 09:25 -0700, Tom Rini wrote:
> > > On Mon, Mar 26, 2012 at 10:15:13AM +0100, Richard Purdie wrote:
> > > > On Fri, 2012-03-23 at 10:35 -0700, Tom Rini wrote:
> > > > > As per
> > > > > http://lists.linuxtogo.org/pipermail/openembedded-core/2012-March/019772.html
> > > > > a machine conf file should use '=' to set IMAGE_FSTYPES.
> > > > > 
> > > > > Signed-off-by: Tom Rini <trini@ti.com>
> > > > > ---
> > > > >  meta/conf/machine/include/qemu.inc |    2 +-
> > > > >  1 files changed, 1 insertions(+), 1 deletions(-)
> > > > 
> > > > As someone pointed out, what I mentioned in that email sadly doesn't
> > > > work although it would be nice if they did. I suspect this is why we're
> > > > using += since:
> > > 
> > > We aren't using += today.  We (openembedded-core) use ?=.  meta-intel
> > > uses += and meta-ti is mixed (and I don't have meta-fsl-* handy).
> > > 
> > > > > - The machine needs to say 'I need or support the following formats'
> > > > 
> > > > so the machine ensures those formats exist at a minimum:
> > > > 
> > > > IMAGE_FSTYPES += "xxxx"
> > > > 
> > > > > - The distro needs to say 'I always want format X'
> > > > 
> > > > so the distro can do:
> > > > 
> > > > IMAGE_FSTYPES += " yyy"
> > > > 
> > > > > - The user needs to say 'I know best, give me only format X'
> > > > 
> > > > This one is the problem case so the user has to use overrides:
> > > > 
> > > > IMAGE_FSTYPES_override = "X"
> > > > 
> > > > (where override can be MACHINE or forcevariable)
> > > > 
> > > > > - The user needs to say 'I know best, give me what you support + X'
> > > > 
> > > > IMAGE_FSTYPES += " X"
> > > > 
> > > > 
> > > > Whilst I think that is less than ideal since it forces use of overrides
> > > > in local.conf to override, changing the += in machine conf files doesn't
> > > > gain us much, it just breaks += in local.conf.
> > > > 
> > > > I'm open to other feedback though...
> > > 
> > > Well, I suggested ??= / ?= and posted some results from bitbake -e...
> > 
> > Ok. += plays out as above. I realise its not what is in qemu.inc, it is
> > used in meta-intel though which I looked at after qemu.inc and I guess
> > has confused me.
> > 
> > With ?= in machine.conf:
> > 
> > The user defined IMAGE_FSTYPES would override the machine ones. Distro
> > can still append to it. The downside is a user append would not work out
> > as expected.
> > 
> > So the question is which is the more user expected behaviour?
> > 
> > =+ makes overwriting IMAGE_FSTYPES hard
> > 
> > ?= makes appending IMAGE_FSTYPES hard
> > 
> > I suspect a user is more likely to want to append than overwrite.
> > Getting an append to work with ?= is extremely non-obvious, even worse
> > syntax than the =+ overwriting case with overrides.
> > 
> > So bottom line, I'm tempted to recommend we use =+.
> > 
> > Further thoughts?
> 
> Richard,
> 
> So, what is the subtle difference between += that we started with and =+ that 
> you recommended at the end? I realize those are for append and prepend, but 
> are they handled any different? Was your recommendation to use =+ at the end, 
> instead of += that was used originally, based on some specifics? Thanks.

I'm using += and =+ interchangeably. The contrast was with ?= which I
argued against. Order in this case doesn't matter and I have no
preference over += or =+, it simply doesn't matter.

Cheers,

Richard
Tom Rini March 28, 2012, 11:29 p.m.
On Wed, Mar 28, 2012 at 10:11:44PM +0100, Richard Purdie wrote:
> On Wed, 2012-03-28 at 14:54 -0400, Denys Dmytriyenko wrote:
> > On Mon, Mar 26, 2012 at 05:56:16PM +0100, Richard Purdie wrote:
> > > On Mon, 2012-03-26 at 09:25 -0700, Tom Rini wrote:
> > > > On Mon, Mar 26, 2012 at 10:15:13AM +0100, Richard Purdie wrote:
> > > > > On Fri, 2012-03-23 at 10:35 -0700, Tom Rini wrote:
> > > > > > As per
> > > > > > http://lists.linuxtogo.org/pipermail/openembedded-core/2012-March/019772.html
> > > > > > a machine conf file should use '=' to set IMAGE_FSTYPES.
> > > > > > 
> > > > > > Signed-off-by: Tom Rini <trini@ti.com>
> > > > > > ---
> > > > > >  meta/conf/machine/include/qemu.inc |    2 +-
> > > > > >  1 files changed, 1 insertions(+), 1 deletions(-)
> > > > > 
> > > > > As someone pointed out, what I mentioned in that email sadly doesn't
> > > > > work although it would be nice if they did. I suspect this is why we're
> > > > > using += since:
> > > > 
> > > > We aren't using += today.  We (openembedded-core) use ?=.  meta-intel
> > > > uses += and meta-ti is mixed (and I don't have meta-fsl-* handy).
> > > > 
> > > > > > - The machine needs to say 'I need or support the following formats'
> > > > > 
> > > > > so the machine ensures those formats exist at a minimum:
> > > > > 
> > > > > IMAGE_FSTYPES += "xxxx"
> > > > > 
> > > > > > - The distro needs to say 'I always want format X'
> > > > > 
> > > > > so the distro can do:
> > > > > 
> > > > > IMAGE_FSTYPES += " yyy"
> > > > > 
> > > > > > - The user needs to say 'I know best, give me only format X'
> > > > > 
> > > > > This one is the problem case so the user has to use overrides:
> > > > > 
> > > > > IMAGE_FSTYPES_override = "X"
> > > > > 
> > > > > (where override can be MACHINE or forcevariable)
> > > > > 
> > > > > > - The user needs to say 'I know best, give me what you support + X'
> > > > > 
> > > > > IMAGE_FSTYPES += " X"
> > > > > 
> > > > > 
> > > > > Whilst I think that is less than ideal since it forces use of overrides
> > > > > in local.conf to override, changing the += in machine conf files doesn't
> > > > > gain us much, it just breaks += in local.conf.
> > > > > 
> > > > > I'm open to other feedback though...
> > > > 
> > > > Well, I suggested ??= / ?= and posted some results from bitbake -e...
> > > 
> > > Ok. += plays out as above. I realise its not what is in qemu.inc, it is
> > > used in meta-intel though which I looked at after qemu.inc and I guess
> > > has confused me.
> > > 
> > > With ?= in machine.conf:
> > > 
> > > The user defined IMAGE_FSTYPES would override the machine ones. Distro
> > > can still append to it. The downside is a user append would not work out
> > > as expected.
> > > 
> > > So the question is which is the more user expected behaviour?
> > > 
> > > =+ makes overwriting IMAGE_FSTYPES hard
> > > 
> > > ?= makes appending IMAGE_FSTYPES hard
> > > 
> > > I suspect a user is more likely to want to append than overwrite.
> > > Getting an append to work with ?= is extremely non-obvious, even worse
> > > syntax than the =+ overwriting case with overrides.
> > > 
> > > So bottom line, I'm tempted to recommend we use =+.
> > > 
> > > Further thoughts?
> > 
> > Richard,
> > 
> > So, what is the subtle difference between += that we started with and =+ that 
> > you recommended at the end? I realize those are for append and prepend, but 
> > are they handled any different? Was your recommendation to use =+ at the end, 
> > instead of += that was used originally, based on some specifics? Thanks.
> 
> I'm using += and =+ interchangeably. The contrast was with ?= which I
> argued against. Order in this case doesn't matter and I have no
> preference over += or =+, it simply doesn't matter.

So I guess I'll spin everything one more time and drop the meta-intel
version and we'll just use += since that's the common one.
Richard Purdie March 29, 2012, 9:51 a.m.
On Wed, 2012-03-28 at 16:29 -0700, Tom Rini wrote:
> On Wed, Mar 28, 2012 at 10:11:44PM +0100, Richard Purdie wrote:
> > On Wed, 2012-03-28 at 14:54 -0400, Denys Dmytriyenko wrote:
> > > On Mon, Mar 26, 2012 at 05:56:16PM +0100, Richard Purdie wrote:
> > > > On Mon, 2012-03-26 at 09:25 -0700, Tom Rini wrote:
> > > So, what is the subtle difference between += that we started with and =+ that 
> > > you recommended at the end? I realize those are for append and prepend, but 
> > > are they handled any different? Was your recommendation to use =+ at the end, 
> > > instead of += that was used originally, based on some specifics? Thanks.
> > 
> > I'm using += and =+ interchangeably. The contrast was with ?= which I
> > argued against. Order in this case doesn't matter and I have no
> > preference over += or =+, it simply doesn't matter.
> 
> So I guess I'll spin everything one more time and drop the meta-intel
> version and we'll just use += since that's the common one.

Sounds good. Sorry about the churn on this one, I thought it was clear
+= and =+ were equivalent in this context.

Cheers,

Richard