LAYERSERIES

A) Some layers only switch to an official branch name when the find a reason to. E.g. branch "sumo" is created on openembedded-core but meta-A keeps working on master unless an incompatible change is created in openembedded-core that forces meta-A to create a "sumo" branch.

B) Other layers create official branches the moment they exist. E.g. branch "sumo" is created on openembedded-core and meta-B instantly creates a "sumo" branch to mark this point in time, and continues working on master. If meta-B's "sumo" branch fails to build against openembedded-core's "sumo" branch because an incompatible change is made to openembedded-core's sumo branch, meta-B fixes the issue on the sumo branch.

I can see how the change you've implemented will be very useful for the A)
cases. Will it be needed for the B) cases? In other words, does the code
you're adding implicitly assume:

	LAYERSERIES_COMPAT_<...> = "layer"

for any given "layer"?

Quoted 21 lines · Trevor Woerner

A) Some layers only switch to an official branch name when the find a reason to. E.g. branch "sumo" is created on openembedded-core but meta-A keeps working on master unless an incompatible change is created in openembedded-core that forces meta-A to create a "sumo" branch.

B) Other layers create official branches the moment they exist. E.g. branch "sumo" is created on openembedded-core and meta-B instantly creates a "sumo" branch to mark this point in time, and continues working on master. If meta-B's "sumo" branch fails to build against openembedded-core's "sumo" branch because an incompatible change is made to openembedded-core's sumo branch, meta-B fixes the issue on the sumo branch.

I can see how the change you've implemented will be very useful for the A)
cases. Will it be needed for the B) cases? In other words, does the code
you're adding implicitly assume:

Quoted 3 lines

      LAYERSERIES_COMPAT_<...> = "layer"

for any given "layer"?

No, there is no implicit assumption.

In both A) and B) cases the maintainer adds the new "codename" to the list of compatible layer series in LAYERSERIES_COMPAT_<layer> for their layer. They can list multiple layers in there, e.g. "rocko sumo".

The one annoying thing about all this is the layer maintainers do have to update layer.conf each time a new release codename comes out. I think that is a reasonable compromise to be able to give users a much better idea of which layers are compatible or incomaptible with their setup though. It means someone has looked at it and believes it will work with a given release series.

Just to be clear, "layer" would never be a valid value there, it will always be the release/branch codenames.

Cheers,

Richard

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We have this variable appearing in a couple manuals BTW.  If anyone has any feedback on what is being said here I can update.

Quoted 2 lines · Scott Rifenbark

We have this variable appearing in a couple manuals BTW. If anyone has any feedback on what is being said here I can update.

Some small suggested tweaks:

"Using the LAYERSERIES_COMPAT variable makes it clear when a given layer is unmaintained and untested with new releases of OE-Core. " ->
"Using the LAYERSERIES_COMPAT variable allows the layer maintainer to indicate which combinations of the layer and OE-Core may be expected to work. It gives the system a way to detect when a layer has not been tested with new releases of OE-Core, for example if it had become unmaintained."

"The OpenEmbedded build system, however, does not produce an error if the variable is not set."
->
"The OpenEmbedded build system will warn if the variable is not set for any given layer"

Cheers,

Richard

Thanks Richard....

https://www.yoctoproject.org/docs/2.5/ref-manual/ref-manual.html#var-
LAYERSERIES_COMPAT

Quoted 21 lines · Trevor Woerner

A) Some layers only switch to an official branch name when the find a reason to. E.g. branch "sumo" is created on openembedded-core but meta-A keeps working on master unless an incompatible change is created in openembedded-core that forces meta-A to create a "sumo" branch.

B) Other layers create official branches the moment they exist. E.g. branch "sumo" is created on openembedded-core and meta-B instantly creates a "sumo" branch to mark this point in time, and continues working on master. If meta-B's "sumo" branch fails to build against openembedded-core's "sumo" branch because an incompatible change is made to openembedded-core's sumo branch, meta-B fixes the issue on the sumo branch.

I can see how the change you've implemented will be very useful for the A)
cases. Will it be needed for the B) cases? In other words, does the code
you're adding implicitly assume:

Quoted 3 lines

      LAYERSERIES_COMPAT_<...> = "layer"

for any given "layer"?

No, there is no implicit assumption.

In both A) and B) cases the maintainer adds the new "codename" to the list of compatible layer series in LAYERSERIES_COMPAT_<layer> for their layer. They can list multiple layers in there, e.g. "rocko sumo".

The one annoying thing about all this is the layer maintainers do have to update layer.conf each time a new release codename comes out. I think that is a reasonable compromise to be able to give users a much better idea of which layers are compatible or incomaptible with their setup though. It means someone has looked at it and believes it will work with a given release series.

Just to be clear, "layer" would never be a valid value there, it will always be the release/branch codenames.

Cheers,

Richard

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Openembedded-architecture mailing list
[email protected]
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FWIW: I've updated some layers with this LAYERSERIES_COMPAT_<layer> today and I think it's good idea.

It probably won't be enough to stop questions like this:
http://lists.openembedded.org/pipermail/openembedded-core/2018-April/
149696.html

but it's still better to show warning first and then some often harder-to-read exception or error log.

Updating layer.conf in meta-qt5 was a bit more tricky as people tend to mix the meta-qt5 branches with different branches of other layers, just because their requirements for Qt are often very different than for other layers (e.g. many people still using meta-qt5/krogoth with Qt 5.6 because of the license, even with much newer morty, pyro, rocko, sumo, master branches of other layers and vice versa that someone is stuck with krogoth release for whatever reason, but needs newer LTS Qt 5.9 from meta-qt5/rocko). So for meta-qt5 I've used multiple values for LAYERSERIES_COMPAT_<layer> for combinations I use

somewhere (so that I cover at least some testing with such uncommon combination) and I'm willing to accept more values to it if someone really uses another combination regularly. The rest of combination (like meta-qt5/krogoth with dizzy, which is usable as described in meta-qt5 commits which introduced incompatiblitites, will eventually trigger the warning which is fine, because people should be aware that they are doing something less tested and that they might to implement some work arounds to make it usable).

Quoted 21 lines · Trevor Woerner

A) Some layers only switch to an official branch name when the find a reason to. E.g. branch "sumo" is created on openembedded-core but meta-A keeps working on master unless an incompatible change is created in openembedded-core that forces meta-A to create a "sumo" branch.

B) Other layers create official branches the moment they exist. E.g. branch "sumo" is created on openembedded-core and meta-B instantly creates a "sumo" branch to mark this point in time, and continues working on master. If meta-B's "sumo" branch fails to build against openembedded-core's "sumo" branch because an incompatible change is made to openembedded-core's sumo branch, meta-B fixes the issue on the sumo branch.

I can see how the change you've implemented will be very useful for the A)
cases. Will it be needed for the B) cases? In other words, does the code
you're adding implicitly assume:

Quoted 3 lines

	LAYERSERIES_COMPAT_<...> = "layer"

for any given "layer"?

No, there is no implicit assumption.

In both A) and B) cases the maintainer adds the new "codename" to the list of compatible layer series in LAYERSERIES_COMPAT_<layer> for their layer. They can list multiple layers in there, e.g. "rocko sumo".

The one annoying thing about all this is the layer maintainers do have to update layer.conf each time a new release codename comes out. I think that is a reasonable compromise to be able to give users a much better idea of which layers are compatible or incomaptible with their setup though. It means someone has looked at it and believes it will work with a given release series.

Just to be clear, "layer" would never be a valid value there, it will always be the release/branch codenames.

Cheers,

Richard

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Openembedded-architecture mailing list
[email protected]
http://lists.openembedded.org/mailman/listinfo/openembedded-architecture

Shouldn't Master get all these changes first then we switch to stable branch when we have a new release?

My German genes are raging about "Rules" ; )

To be really clear, "master" is never a value that would appear in LAYERSERIES. That would let everyone be lazy and master would match everywhere, then this would all be pointless.

Quoted 4 lines · Richard Purdie

To be really clear, "master" is never a value that would appear in LAYERSERIES. That would let everyone be lazy and master would match everywhere, then this would all be pointless.

So what happens when the master branch of a BSP layer doesn't work with the
last release, but bitbake hasn't been updated with the next release's name?

I.e. the sumo branch of meta-bsp has

LAYERSERIES_COMPAT_bsp = "sumo"

but what am I supposed to put as the value when meta-bsp's master branch
becomes incompatible with sumo? "master" is not allowed, and "thud" fails too.

At some point between one release and the next something might/will break. In
which case the only thing a BSP's master branch will work with is openembedded-core's master.

I finally found 5 mins to sit and look at where I'd gotten to with the LAYERSERIES variable handling. I sent out discussion about this a while ago but as a reminder:

We have a problem where people expect master branch of meta-X to work with OE-Core master. If meta-X hasn't been maintained for a long time, this may give all kinds of weird errors. This creates a large support burden and means we struggle to spot unmaintained/un-updated layers. We'd like to fix this.

In answer to this I added LAYERSERIES_CORENAMES to OE-Core and strongly suggest layers then set:

LAYERSERIES_COMPAT_xxx = "sumo"

in their layer.conf where xxx is the collection name (used elsewhere in layer.conf) to indicate which versions of OE-Core they're expected to work against.

The code already exists to validate this with a fatal error for mismatches. What was missing was:

a) to print a warning if LAYERSERIES_COMPAT_xxx is unset. I've a patch queued for bitbake to add this.
b) add a check to yocto-check-layer and require this to be set for YP Compatible v2. I've added
   https://bugzilla.yoctoproject.org/show_bug.cgi?id=12661
   to track this.

Yes, its late in the release and the warnings will be annoying but I think its worth fixing this now so I'm pushing ahead to resolve this.

Cheers,

Richard

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I understand the need to reduce the support burden. But there are some valid
cases when you want to use components/layers from a different set of releases.

It can sometimes be an older component in otherwise newer setup (i.e. one
layer hasn't been updated yet from rocko, but it still works fine with
everything else from sumo).

Alternatively, sometimes you need to bring a newer version of the component to
your older release - as long as it works for me, I don't want this to be
artificially restricted.

In other words, the intention is good, but it needs to be either more flexible or allow overriding this from distro config or local.conf...