[PATCH 6/6] lib: Drop internal virXXXPtr typedefs

[Michal Privoznik]

On 3/11/21 7:47 PM, Daniel P. Berrangé wrote:
> On Thu, Mar 11, 2021 at 06:54:20PM +0100, Michal Privoznik wrote:
>> Historically, we declared pointer type to our types:
>>
>>    typedef struct _virXXX virXXX;
>>    typedef virXXX *virXXXPtr;
>>
>> But usefulness of such declaration is questionable, at best.
>> Unfortunately, we can't drop every such declaration - we have to
>> carry some over, because they are part of public API (e.g.
>> virDomainPtr). But for internal types - we can do drop them and
>> use what every other C project uses 'virXXX *'.
>>
>> This change was generated by a very ugly shell script that
>> generated sed script which was then called over each file in the
>> repository. For the shell script refer to the cover letter:
>>
>> $URL
>>
>> Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
>> ---
>>   docs/advanced-tests.rst                       |    2 +-
>>   docs/api_extension.html.in                    |    2 +-
>>   docs/coding-style.rst                         |    2 +-
> 
> snip
> 
>>   tools/virt-login-shell-helper.c               |    4 +-
>>   tools/vsh-table.c                             |   36 +-
>>   tools/vsh-table.h                             |   12 +-
>>   tools/vsh.c                                   |    4 +-
>>   732 files changed, 29237 insertions(+), 30131 deletions(-)
> 
> Converting every single file at the same time in one commit is
> guaranting backporting conflict hell.
> 
> eg if I'm backporting a patch from src/qemu, it is much
> saner if I can cherry-pick the "Ptr" conversion from src/qemu
> and only deal with conflicts in that, not the entire soure
> tree.
> 
> So if we're going to do this conversion, IMHO the actual commits
> need to be way more granular. At the very least I think this
> needs to be split per driver, with tests/ associated with their
> driver. The util/ directory needs to be split up and likewise
> the conf/ directory per object type I think.

I though about it this way too, but then I realized, that the only type 
of merge conflicts we will get while backporting is context. I mean, 
after this commit, every subsequent commit will use 'virXXX *' which is 
perfectly okay even now. And thus what we might get the only type of 
conflict - cherry picked commit already expects 'virXXX *' (e.g. it 
renames a variable), but the downstream has 'virXXXPtr'. But this kind 
of conflict is trivial to resolve.

Another reason to put it into one huge patch was to not bother with 
dependencies. It's not uncommon that our commits touch different 
locations at the same time, they are not strictly aiming on one 
submodule (e.g. src/conf and src/qemu at the same time, or src/util and 
tools/virsh). The point is, making the granularity satisfactory fine 
grained is hard.

> 
> Also dropping usage of the "Ptr" should be separate from dropping
> the typedefs themselves as I think that'll make conflicts easier
> to deal with.

Yeah, this makes sense. I'll split it.

Michal