[PATCH] migration-guides: Add start of 3.4 guide with override migration notes

[PATCH] migration-guides: Add start of 3.4 guide with override migration notes

[Richard Purdie]

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
---
 documentation/migration-guides/index.rst      |  1 +
 .../migration-guides/migration-3.4.rst        | 72 +++++++++++++++++++
 2 files changed, 73 insertions(+)
 create mode 100644 documentation/migration-guides/migration-3.4.rst

diff --git a/documentation/migration-guides/index.rst b/documentation/migration-guides/index.rst
index 6304e6318..287b55319 100644
--- a/documentation/migration-guides/index.rst
+++ b/documentation/migration-guides/index.rst
@@ -12,6 +12,7 @@ to move to one release of the Yocto Project from the previous one.
 .. toctree::
 
    migration-general
+   migration-3.4
    migration-3.3
    migration-3.2
    migration-3.1
diff --git a/documentation/migration-guides/migration-3.4.rst b/documentation/migration-guides/migration-3.4.rst
new file mode 100644
index 000000000..45ce38cd6
--- /dev/null
+++ b/documentation/migration-guides/migration-3.4.rst
@@ -0,0 +1,72 @@
+Release 3.4 (honister)
+======================
+
+This section provides migration information for moving to the Yocto
+Project 3.4 Release (codename "honister") from the prior release.
+
+Override syntax changes
+-----------------------
+
+This release requires changes to the metadata to indicate where overrides are
+being used in variable key names. This is done with the ":" character replacing
+the use of "_" previously. This means that an entry like::
+
+   SRC_URI_qemux86 = "file://somefile"
+
+becomes::
+
+   SRC_URI:qemux86 = " file://somefile"
+
+since qemux86 is an override. This applies to any use of override syntax so::
+
+   SRC_URI_append = " file://somefile"
+   SRC_URI_append_qemux86 = " file://somefile2"
+   SRC_URI_remove_qemux86-64 = " file://somefile3"
+   SRC_URI_prepend_qemuarm = "file://somefile4 "
+   FILES_${PN}-ptest = "${bindir}/xyz"
+   IMAGE_CMD_tar = "tar"
+   BASE_LIB_tune-coretexa76 = "lib"
+   SRCREV_pn-bash = "abc"
+   BB_TASK_NICE_LEVEL_task-testimage = '0'
+
+becomes::
+
+   SRC_URI:append = " file://somefile"
+   SRC_URI:append:qemux86 = " file://somefile2"
+   SRC_URI:remove:qemux86-64 = " file://somefile3"
+   SRC_URI:prepend:qemuarm = "file://somefile4 "
+   FILES:${PN}-ptest = "${bindir}/xyz"
+   IMAGE_CMD:tar = "tar"
+   BASE_LIB:tune-coretexa76 = "lib"
+   SRCREV:pn-bash = "abc"
+   BB_TASK_NICE_LEVEL:task-testimage = '0'
+
+This also applies to variable queries to the datastore, for example using getVar 
+and similar so d.getVar("RDEPENDS_${PN}") becomes d.getVar("RDEPENDS:${PN}").
+
+Whilst some of these are fairly obvious such as MACHINE and DISTRO overrides, some
+are less obvious, for example the packaging variables such as RDEPENDS, FILES and 
+so on taking package names (e.g. ${PN}, ${PN}-ptest) as overrides. These overrides 
+are not always applies in OVERRIDES but applied conditionally in specific contexts
+such as packaging. The task-<taskname> is another context specific override, the 
+context being specific tasks in that case. Tune overrides are another specialist
+case where some code does use them as overrides but some does not. We plan to try
+and make the tune code use overrides more consistently in the future.
+
+To help with migration of layers there is a script in OE-Core. Once configured
+with the overrides used by a layer, this can be run as::
+
+   <oe-core>/scripts/contrib/convert-overrides.py <layerdir>
+
+Please read the notes in the script as it isn't entirely automatic and it isn't
+expected to handle every case. In particular, it needs to be told which overrides
+the layer uses (usually machine and distro names/overrides) and the result should
+be carefully checked since it can be a little enthusiastic and will convert
+references to "_append", "_remove" and "_prepend" in function and variables names.
+
+For reference, this conversion is important as it allows bitbake to know what is
+an override and what is not. This should allow us to proceed with other syntax
+improvements and simplifications for usability. It also means bitbake no longer
+has to guess and maintain large lookup lists just in case "functionname" in
+"my_functionname" is an override and this should improve efficiency.
+
-- 
2.30.2

Re: [docs] [PATCH] migration-guides: Add start of 3.4 guide with override migration notes

[Quentin Schulz]

Hi Richard,

On Thu, Jul 29, 2021 at 11:09:45PM +0100, Richard Purdie wrote:
> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
> ---
>  documentation/migration-guides/index.rst      |  1 +
>  .../migration-guides/migration-3.4.rst        | 72 +++++++++++++++++++
>  2 files changed, 73 insertions(+)
>  create mode 100644 documentation/migration-guides/migration-3.4.rst
> 
> diff --git a/documentation/migration-guides/index.rst b/documentation/migration-guides/index.rst
> index 6304e6318..287b55319 100644
> --- a/documentation/migration-guides/index.rst
> +++ b/documentation/migration-guides/index.rst
> @@ -12,6 +12,7 @@ to move to one release of the Yocto Project from the previous one.
>  .. toctree::
>  
>     migration-general
> +   migration-3.4
>     migration-3.3
>     migration-3.2
>     migration-3.1
> diff --git a/documentation/migration-guides/migration-3.4.rst b/documentation/migration-guides/migration-3.4.rst
> new file mode 100644
> index 000000000..45ce38cd6
> --- /dev/null
> +++ b/documentation/migration-guides/migration-3.4.rst
> @@ -0,0 +1,72 @@
> +Release 3.4 (honister)
> +======================
> +
> +This section provides migration information for moving to the Yocto
> +Project 3.4 Release (codename "honister") from the prior release.
> +
> +Override syntax changes
> +-----------------------
> +
> +This release requires changes to the metadata to indicate where overrides are
> +being used in variable key names. This is done with the ":" character replacing
> +the use of "_" previously. This means that an entry like::
> +
> +   SRC_URI_qemux86 = "file://somefile"
> +
> +becomes::
> +
> +   SRC_URI:qemux86 = " file://somefile"
> +

Is the leading space here on purpose?

> +since qemux86 is an override. This applies to any use of override syntax so::
> +

I'm pondering whether we should quote or tick quote qemux86?

> +   SRC_URI_append = " file://somefile"
> +   SRC_URI_append_qemux86 = " file://somefile2"
> +   SRC_URI_remove_qemux86-64 = " file://somefile3"
> +   SRC_URI_prepend_qemuarm = "file://somefile4 "
> +   FILES_${PN}-ptest = "${bindir}/xyz"
> +   IMAGE_CMD_tar = "tar"
> +   BASE_LIB_tune-coretexa76 = "lib"

s/BASE_LIB_tune-coretexa76/BASE_LIB_tune-cortexa76/

> +   SRCREV_pn-bash = "abc"
> +   BB_TASK_NICE_LEVEL_task-testimage = '0'
> +
> +becomes::
> +
> +   SRC_URI:append = " file://somefile"
> +   SRC_URI:append:qemux86 = " file://somefile2"
> +   SRC_URI:remove:qemux86-64 = " file://somefile3"
> +   SRC_URI:prepend:qemuarm = "file://somefile4 "
> +   FILES:${PN}-ptest = "${bindir}/xyz"
> +   IMAGE_CMD:tar = "tar"
> +   BASE_LIB:tune-coretexa76 = "lib"

s/BASE_LIB:tune-coretexa76/BASE_LIB:tune-cortexa76/

> +   SRCREV:pn-bash = "abc"
> +   BB_TASK_NICE_LEVEL:task-testimage = '0'
> +
> +This also applies to variable queries to the datastore, for example using getVar 
> +and similar so d.getVar("RDEPENDS_${PN}") becomes d.getVar("RDEPENDS:${PN}").
> +

Probably would benefit from tick quotes?

> +Whilst some of these are fairly obvious such as MACHINE and DISTRO overrides, some

s/MACHINE/:term:`MACHINE`/

Ditto for DISTRO.

> +are less obvious, for example the packaging variables such as RDEPENDS, FILES and 

Ditto for RDEPENDS and FILES.

> +so on taking package names (e.g. ${PN}, ${PN}-ptest) as overrides. These overrides 

Tick quotes for ${PN}?

> +are not always applies in OVERRIDES but applied conditionally in specific contexts

s/OVERRIDES/:term:`OVERRIDES`/

s/applies// ?

> +such as packaging. The task-<taskname> is another context specific override, the 

Tick quoting task-<taskname>?

> +context being specific tasks in that case. Tune overrides are another specialist

s/specialist/special/ ?

> +case where some code does use them as overrides but some does not. We plan to try
> +and make the tune code use overrides more consistently in the future.
> +
> +To help with migration of layers there is a script in OE-Core. Once configured

Add a link to this script whose text is "a script in OE-Core"? (I know
it's mentioned below).

> +with the overrides used by a layer, this can be run as::
> +
> +   <oe-core>/scripts/contrib/convert-overrides.py <layerdir>
> +
> +Please read the notes in the script as it isn't entirely automatic and it isn't
> +expected to handle every case. In particular, it needs to be told which overrides
> +the layer uses (usually machine and distro names/overrides) and the result should
> +be carefully checked since it can be a little enthusiastic and will convert
> +references to "_append", "_remove" and "_prepend" in function and variables names.
> +

Pondering whether the one (or two) paragpraphs above should be in a
..note section to highlight it.

> +For reference, this conversion is important as it allows bitbake to know what is
> +an override and what is not. This should allow us to proceed with other syntax
> +improvements and simplifications for usability. It also means bitbake no longer
> +has to guess and maintain large lookup lists just in case "functionname" in
> +"my_functionname" is an override and this should improve efficiency.
> +

Thanks for the patch :)

Cheers,
Quentin

Re: [docs] [PATCH] migration-guides: Add start of 3.4 guide with override migration notes

[Michael Opdenacker]

Richard, thanks for the patch
Quentin, thanks for the review

I'm taking care of preparing a V2 to reduce the load on Richard's
shoulders...

On 7/30/21 10:16 AM, Quentin Schulz wrote:
> Hi Richard,
>
> On Thu, Jul 29, 2021 at 11:09:45PM +0100, Richard Purdie wrote:
>> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
>> ---
>>  documentation/migration-guides/index.rst      |  1 +
>>  .../migration-guides/migration-3.4.rst        | 72 +++++++++++++++++++
>>  2 files changed, 73 insertions(+)
>>  create mode 100644 documentation/migration-guides/migration-3.4.rst
>>
>> diff --git a/documentation/migration-guides/index.rst b/documentation/migration-guides/index.rst
>> index 6304e6318..287b55319 100644
>> --- a/documentation/migration-guides/index.rst
>> +++ b/documentation/migration-guides/index.rst
>> @@ -12,6 +12,7 @@ to move to one release of the Yocto Project from the previous one.
>>  .. toctree::
>>  
>>     migration-general
>> +   migration-3.4
>>     migration-3.3
>>     migration-3.2
>>     migration-3.1
>> diff --git a/documentation/migration-guides/migration-3.4.rst b/documentation/migration-guides/migration-3.4.rst
>> new file mode 100644
>> index 000000000..45ce38cd6
>> --- /dev/null
>> +++ b/documentation/migration-guides/migration-3.4.rst
>> @@ -0,0 +1,72 @@
>> +Release 3.4 (honister)
>> +======================
>> +
>> +This section provides migration information for moving to the Yocto
>> +Project 3.4 Release (codename "honister") from the prior release.
>> +
>> +Override syntax changes
>> +-----------------------
>> +
>> +This release requires changes to the metadata to indicate where overrides are
>> +being used in variable key names. This is done with the ":" character replacing
>> +the use of "_" previously. This means that an entry like::
>> +
>> +   SRC_URI_qemux86 = "file://somefile"
>> +
>> +becomes::
>> +
>> +   SRC_URI:qemux86 = " file://somefile"
>> +
> Is the leading space here on purpose?


Assuming that's a typo. Fixed.

>
>> +since qemux86 is an override. This applies to any use of override syntax so::
>> +
> I'm pondering whether we should quote or tick quote qemux86?


I'll set it to ``qemux86`` but I plan to write some documentation coding
style so that we know which conventions to follow.

>
>> +   SRC_URI_append = " file://somefile"
>> +   SRC_URI_append_qemux86 = " file://somefile2"
>> +   SRC_URI_remove_qemux86-64 = " file://somefile3"
>> +   SRC_URI_prepend_qemuarm = "file://somefile4 "
>> +   FILES_${PN}-ptest = "${bindir}/xyz"
>> +   IMAGE_CMD_tar = "tar"
>> +   BASE_LIB_tune-coretexa76 = "lib"
> s/BASE_LIB_tune-coretexa76/BASE_LIB_tune-cortexa76/


Fixed.

>> +   SRCREV:pn-bash = "abc"
>> +   BB_TASK_NICE_LEVEL:task-testimage = '0'
>> +
>> +This also applies to variable queries to the datastore, for example using getVar 
>> +and similar so d.getVar("RDEPENDS_${PN}") becomes d.getVar("RDEPENDS:${PN}").
>> +
> Probably would benefit from tick quotes?

Done
>
>> +Whilst some of these are fairly obvious such as MACHINE and DISTRO overrides, some
> s/MACHINE/:term:`MACHINE`/
>
> Ditto for DISTRO.
>
>> +are less obvious, for example the packaging variables such as RDEPENDS, FILES and 
> Ditto for RDEPENDS and FILES.

Fixed
>
>> +so on taking package names (e.g. ${PN}, ${PN}-ptest) as overrides. These overrides 
> Tick quotes for ${PN}?
>
>> +are not always applies in OVERRIDES but applied conditionally in specific contexts
> s/OVERRIDES/:term:`OVERRIDES`/


All fixed!

>
> s/applies// ?

I first felt like writing "applied" instead, but this makes sense too.
The sentence is now:

"These overrides are not always in
:term:`OVERRIDES` but applied conditionally in specific contexts
such as packaging"

>
>> +such as packaging. The task-<taskname> is another context specific override, the 
> Tick quoting task-<taskname>?


Yes

>
>> +context being specific tasks in that case. Tune overrides are another specialist
> s/specialist/special/ ?

Make sense
>
>> +case where some code does use them as overrides but some does not. We plan to try
>> +and make the tune code use overrides more consistently in the future.
>> +
>> +To help with migration of layers there is a script in OE-Core. Once configured
> Add a link to this script whose text is "a script in OE-Core"? (I know
> it's mentioned below).
>
>> +with the overrides used by a layer, this can be run as::
>> +
>> +   <oe-core>/scripts/contrib/convert-overrides.py <layerdir>


I'm not sure about what you're proposing here. I believe we currently
don't put hyperlinks to source code in the documentation, we just
mention the file paths. We could though.

>> +
>> +Please read the notes in the script as it isn't entirely automatic and it isn't
>> +expected to handle every case. In particular, it needs to be told which overrides
>> +the layer uses (usually machine and distro names/overrides) and the result should
>> +be carefully checked since it can be a little enthusiastic and will convert
>> +references to "_append", "_remove" and "_prepend" in function and variables names.
>> +
> Pondering whether the one (or two) paragpraphs above should be in a
> ..note section to highlight it.


Good idea, I put the first paragraph in a note. I didn't want the second
paragraph to be in the same note. This way it's more visible IMHO.

I'll submit my V2 soon.

Thanks again,

Michael.

-- 
Michael Opdenacker, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com