[package] protobuf/*: incorrect RPATH on MacOS w/ with_zlib=True

[Cogitri]

Description

When building protobuf on MacOS with with_zlib=True, the package_folder of zlib isn't included in protobuf's RPATH. As such, running protoc fails because it can't find @rpath/zlib.dylib.

Package and Environment Details

• Package Name/Version: protobuf/3.21.12
• Operating System+version: MacOS 13.5.1
• Compiler+version: Apple clang version 15.0.0 (clang-1500.0.40.1)
• Conan version: conan 2.0.9
• Python version: Python 3.11.3

Conan profile

[settings]
arch = x86_64
build_type = Release
compiler = apple-clang
compiler.cppstd = 20
compiler.libcxx = libc++
compiler.version = 15
os = Macos
os.version = 10.15

Steps to reproduce

conan install -r conancenter--requires=protobuf/3.21.12 -o "*:shared=True"

Logs

Click to expand log

dyld[44252]: Library not loaded: @rpath/libz.1.dylib
  Referenced from: <12487EAF-0251-3D44-A4C3-7E4721B31A02> /Users/dev/.conan2/p/b/proto7bde3c2dd0ea7/p/lib/libprotobufd.3.21.12.0.dylib
  Reason: tried: '/Users/dev/.conan2/p/b/proto7bde3c2dd0ea7/p/lib/libz.1.dylib' (no such file), '/Users/dev/.conan2/p/b/proto7bde3c2dd0ea7/p/lib/libz.1.dylib' (no such file), '/Users/dev/.conan2/p/b/proto7bde3c2dd0ea7/p/bin/../lib/libz.1.dylib' (no such file), '/Users/dev/.conan2/p/b/proto7bde3c2dd0ea7/p/bin/../lib/libz.1.dylib' (no such file)

[Cogitri]

Probably similar to #20093 (comment)

[SpaceIm]

When building protobuf on MacOS with with_zlib=True, the package_folder of zlib isn't included in protobuf's RPATH. As such, running protoc fails because it can't find @rpath/zlib.dylib.

Adding zlib to LC_RPATH of protoc executable or protobuf lib is not a long term solution, since zlib path in conan cache can change (if protobuf has been built on another machine, or if another flavor of zlib than the one used during build and not leading to a rebuild of protobuf is injected in the dependency graph).

Apple SIP reseting DYLD_LIBRARY_PATH defeats VirtualBuildEnv or VirtualRunEnv (SIP is triggered somewhere during execution of build backends like make or ninja), and there is nothing conan can do against this anti-developer feature.

My advice is to have protobuf/<host_version> in tool_requires when protoc is needed at build time (native or cross-build, no trick with protobuf from host context used with VirtualRunEnv injected in build scope), and avoid to inject shared=True in build context.

[Cogitri]

Ah, that makes sense. We'll just have to build protobuf w/ zlib:shared=False then