[protobuf] Enable Android/iOS cross building

[anton-danielsson]

Specify library name and version: protobuf/3.13.0

Allows protobuf to be cross built using dual profiles (profile host/build).

Test changed to also build when cross building.
As the test shows a client recipe should typically have both a requires and build requires to protobuf.
One will provide the libraries for the host environment while the other one will proved protoc for the build environment.

I first considered adding an option like "protobuf:tools" that controls if protoc is included or not.
But it seems that Conan has a bug that means you can't have different options for a recipe is in the build and host requirement.
That meant I couldn't have protobuf:tools set to False in host and True in build...
I think it's the same problem as here: conan-io/conan#8443

Has been tested on both android and ios:

Android profile:

Configuration (profile_host):
[settings]
arch=armv8
build_type=Release
compiler=clang
compiler.libcxx=c++_static
compiler.version=11
os=Android
os.api_level=21
[options]
[build_requires]
*: android-ndk/r22
[env]

Configuration (profile_build):
[settings]
arch=x86_64
build_type=Release
compiler=Visual Studio
compiler.runtime=MD
compiler.version=16
os=Windows
[options]
[build_requires]
[env]

iOS profile:

Configuration (profile_host):
[settings]
arch=armv8
build_type=Release
compiler=apple-clang
compiler.libcxx=libc++
compiler.version=11.0
os=iOS
os.version=10.2
[options]
ios-cmake:enable_bitcode=False
[build_requires]
*: ios-cmake/3.1.2
[env]

Configuration (profile_build):
[settings]
arch=x86_64
build_type=Release
compiler=apple-clang
compiler.libcxx=libc++
compiler.version=11.0
os=Macos
[options]
[build_requires]
[env]

• I've read the guidelines for contributing.
• I've followed the PEP8 style guides for Python code in the recipes.
• I've used the latest Conan client version.
• I've tried at least one configuration locally with the
  conan-center hook activated.

[prince-chrismc]

This will require a CCI team member review, I have no clue about this stuff 👀

Great work though!

[anton-danielsson]

Is the build still running two days later? 😮

[prince-chrismc]

no it's been a bug recently in CCI the update status got lost...

Close the PR wait 10s and then reopen... that will retrigger CI to run

[conan-center-bot]

Sorry, the build is only launched for Early Access Program users. You can request access writing in this issue.

[anton-danielsson]

Oh... I changed my username a few days ago and now it seems I need to apply for the EAP program again...
I'll do that.

[prince-chrismc]

Oh... I changed my username a few days ago and now it seems I need to apply for the EAP program again...

@danimtb is this something the conan team can help with?

[danimtb]

It is done! Thanks for the ping 😄

[prince-chrismc]

LGTM!

👏 for all the upstream PRs

[conan-center-bot]

All green in build 9 (08297d78d5b4a18a2bd9ac7639f0462c70e8dc5a)! 😊

• protobuf/3.9.1: Generated 124 packages. All logs here
• protobuf/3.11.4: Generated 124 packages. All logs here
• protobuf/3.12.4: Generated 124 packages. All logs here
• protobuf/3.13.0: Generated 124 packages. All logs here

[uilianries]

I first considered adding an option like "protobuf:tools" that controls if protoc is included or not.

Please, remove. Since Bincrafters we tried to do it, at first sight was easy, but after each version update became a hell because that issue you pointed and we need to update each patch. So we unified protoc and protobuf again. If will accept such option, it should be official in the future, so let's wait become official. Keep you PR focused on your feature only, enabling Android building.

[ericLemanissierBot]

I detected other pull requests that are modifying protobuf/all recipe:

• protobuf: allow shared on Macos + add protobuf::protoc imported target #4776

This message is automatically generated by https://github.com/ericLemanissier/conan-center-conflicting-prs so don't hesitate to report issues/improvements there.

[anton-danielsson]

Reviewers: Any more comments? Should I change something or what do you think?

[uilianries]

My comment is still the same. No Tools! Keep focused in your PR, solve only the problem related to Android.

[conan-center-bot]

All green in build 18 (6a14a091f3b63f0f7039520d03627c607e58f770):

• protobuf/3.9.1@:
  All packages built successfully! (All logs)

• protobuf/3.11.4@:
  All packages built successfully! (All logs)

• protobuf/3.12.4@:
  All packages built successfully! (All logs)

• protobuf/3.13.0@:
  All packages built successfully! (All logs)

[mathbunnyru]

@anton-danielsson please, do not use push-force after PR creation.
It makes it difficult to see the changes.
And, it might be nice to see the history of changes during PR.

[mjvankampen]

I didn't look at everything, but flatbuffers had a similar issue that was done in a bit different way. https://github.com/conan-io/conan-center-index/blob/master/recipes/flatbuffers/all/conanfile.py . Is the protobuf way the preferred way to tackle this?

[anton-danielsson]

I didn't look at everything, but flatbuffers had a similar issue that was done in a bit different way. https://github.com/conan-io/conan-center-index/blob/master/recipes/flatbuffers/all/conanfile.py . Is the protobuf way the preferred way to tackle this?

From what I understand one difference is that the flatbuffers recipe automatically disables the build of flatc for the in the host context.
I also did that (or a very similar thing) in the beginning but it was changed after review comments.
This is also what we have done in our private fork of the protobuf recipe.
For me it doesn't really matter which way we go, I just want cross building to Android and iOS to work :)

[prince-chrismc]

I just want cross building to Android and iOS to work :)

So do we! Thanks for all your hard work!

[anton-danielsson]

Had to make a small update (facc289) after #4682 was merged.
Means the approvals where reset again.

[prince-chrismc]

You'll need to retrigger CI, close the pr wait 10s and then re-open it 🔁

[conan-center-bot]

All green in build 20 (facc2895230f752557d90c3e7e5c005147193ba9):

• protobuf/3.9.1@:
  All packages built successfully! (All logs)

• protobuf/3.11.4@:
  All packages built successfully! (All logs)

• protobuf/3.12.4@:
  All packages built successfully! (All logs)

• protobuf/3.13.0@:
  All packages built successfully! (All logs)

• protobuf/3.15.5@:
  All packages built successfully! (All logs)