Libguestfs - Nov 2021 - [PATCH v4 5/5] block: Deprecate transaction type drive-backup

Several moons ago, Vladimir posted

    Subject: [PATCH v2 3/3] qapi: deprecate drive-backup
    Date: Wed,  5 May 2021 16:58:03 +0300
    Message-Id: <20210505135803.67896-4-vsementsov at virtuozzo.com>
    https://lists.gnu.org/archive/html/qemu-devel/2021-05/msg01394.html

with this

    TODO: We also need to deprecate drive-backup transaction action..
    But union members in QAPI doesn't support 'deprecated' feature.
I tried
    to dig a bit, but failed :/ Markus, could you please help with it? At
    least by advice?

This is one way to resolve it.  Sorry it took so long.

John explored another way, namely adding feature flags to union
branches.  Could also be useful, say to add different features to
branches in multiple unions sharing the same tag enum.

Signed-off-by: Markus Armbruster <armbru at redhat.com>
---
 qapi/transaction.json | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/qapi/transaction.json b/qapi/transaction.json
index d175b5f863..381a2df782 100644
--- a/qapi/transaction.json
+++ b/qapi/transaction.json
@@ -54,6 +54,10 @@
 # @blockdev-snapshot-sync: since 1.1
 # @drive-backup: Since 1.6
 #
+# Features:
+# @deprecated: Member @drive-backup is deprecated.  Use member
+#              @blockdev-backup instead.
+#
 # Since: 1.1
 ##
 { 'enum': 'TransactionActionKind',
@@ -62,7 +66,7 @@
             'block-dirty-bitmap-disable',
'block-dirty-bitmap-merge',
             'blockdev-backup', 'blockdev-snapshot',
             'blockdev-snapshot-internal-sync',
'blockdev-snapshot-sync',
-            'drive-backup' ] }
+            { 'name': 'drive-backup', 'features': [
'deprecated' ] } ] }
 
 ##
 # @AbortWrapper:
-- 
2.31.1

I neglected to put RFC in the subject.

On Mon, Oct 25, 2021 at 12:24 AM Markus Armbruster <armbru at redhat.com>
wrote:
> Several moons ago, Vladimir posted
>
>     Subject: [PATCH v2 3/3] qapi: deprecate drive-backup
>     Date: Wed,  5 May 2021 16:58:03 +0300
>     Message-Id: <20210505135803.67896-4-vsementsov at virtuozzo.com>
>     https://lists.gnu.org/archive/html/qemu-devel/2021-05/msg01394.html
>
> with this
>
>     TODO: We also need to deprecate drive-backup transaction action..
>     But union members in QAPI doesn't support 'deprecated'
feature. I tried
>     to dig a bit, but failed :/ Markus, could you please help with it? At
>     least by advice?
>
> This is one way to resolve it.  Sorry it took so long.
>
>
I'll share the blame for not pushing back on the other series, but ...

> John explored another way, namely adding feature flags to union
> branches.  Could also be useful, say to add different features to
> branches in multiple unions sharing the same tag enum.
>
>
... this way seems simpler for now, and I trust your intuition on what's
easier to support as I don't have a solid grasp of the C interfaces at play
for actually parsing the input. We can always revisit the other thing later
if/when we need it.

> Signed-off-by: Markus Armbruster <armbru at redhat.com>
> ---
>  qapi/transaction.json | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/qapi/transaction.json b/qapi/transaction.json
> index d175b5f863..381a2df782 100644
> --- a/qapi/transaction.json
> +++ b/qapi/transaction.json
> @@ -54,6 +54,10 @@
>  # @blockdev-snapshot-sync: since 1.1
>  # @drive-backup: Since 1.6
>  #
> +# Features:
> +# @deprecated: Member @drive-backup is deprecated.  Use member
> +#              @blockdev-backup instead.
> +#
>  # Since: 1.1
>  ##
>  { 'enum': 'TransactionActionKind',
> @@ -62,7 +66,7 @@
>              'block-dirty-bitmap-disable',
'block-dirty-bitmap-merge',
>              'blockdev-backup', 'blockdev-snapshot',
>              'blockdev-snapshot-internal-sync',
'blockdev-snapshot-sync',
> -            'drive-backup' ] }
> +            { 'name': 'drive-backup', 'features':
[ 'deprecated' ] } ] }
>
>  ##
>  # @AbortWrapper:
> --
> 2.31.1
>
>
Seems pretty clean to me overall. What's the reason for wanting it to be
RFC?
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://listman.redhat.com/archives/libguestfs/attachments/20211026/19ea64cd/attachment.htm>

25.10.2021 07:24, Markus Armbruster wrote:
> Several moons ago, Vladimir posted
> 
>      Subject: [PATCH v2 3/3] qapi: deprecate drive-backup
>      Date: Wed,  5 May 2021 16:58:03 +0300
>      Message-Id:<20210505135803.67896-4-vsementsov at virtuozzo.com>
>      https://lists.gnu.org/archive/html/qemu-devel/2021-05/msg01394.html
> 
> with this
> 
>      TODO: We also need to deprecate drive-backup transaction action..
>      But union members in QAPI doesn't support 'deprecated'
feature. I tried
>      to dig a bit, but failed :/ Markus, could you please help with it? At
>      least by advice?
> 
> This is one way to resolve it.  Sorry it took so long.
> 
> John explored another way, namely adding feature flags to union
> branches.  Could also be useful, say to add different features to
> branches in multiple unions sharing the same tag enum.
> 
> Signed-off-by: Markus Armbruster<armbru at redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov at virtuozzo.com>

(with simplified commit message of course :)

-- 
Best regards,
Vladimir