Realm-cocoa: "visibility settings" error in core when building via CocoaPods

[yuggieg]

Hi Guys,

After updating to Realm 2.3.0 (was 2.1.2), I get the following warning in Xcode:

direct access in function 'realm::SharedGroup::SharedGroup(realm::Replication&, realm::SharedGroupOptions)' from file '/Users/xxxx/Documents/Projects/ImageScape/Pods/Realm/core/librealm-ios.a(client_file_access_cache-iphonesimulator.o)' to global weak symbol 'realm::util::InterprocessMutex::initialize_statics()' from file '/Users/xxxx/Library/Developer/Xcode/DerivedData/ImageScape-hetxuiirverpbbdrqeqlutdnufdo/Build/Products/Debug-iphonesimulator/Realm/libRealm.a(shared_realm.o)' means the weak symbol cannot be overridden at runtime. This was likely caused by different translation units being compiled with different visibility settings.

As far as I can check everything works as expected, but the warning isn't nice of course. Thanks!

Script info:

ProductName:    Mac OS X
ProductVersion: 10.12.2
BuildVersion:   16C67

/Applications/Xcode.app/Contents/Developer
Xcode 8.2.1
Build version 8C1002

/usr/local/bin/pod
1.0.0
Realm (2.3.0)

/bin/bash
GNU bash, version 3.2.57(1)-release (x86_64-apple-darwin16)

/usr/local/bin/carthage
0.18.1
(not in use here)

/usr/bin/git
git version 2.10.1 (Apple Git-78)

[luna-kx]

Thanks for reporting this, @yuggieg! Would you be able to provide a sample project that reproduces the issue so we can better debug this? Cheers! :-)

[jpsim]

No need to send us a repro case @yuggieg, we can see this too. This is a similar linker warning as realm/realm-object-store/issues/281 and https://github.com/realm/realm-cocoa/issues/4438. I thought we had updated our upstream projects to use the same visibility settings, but evidently that's not the case. I'm looking into this.

[iMark21]

Hi! Same problem on 2.4.2

[luna-kx]

@jpsim ^

[DiER-WANG]

install realm by pod could cause it on 2.4.2 and wouldn't appear install by static framework

[ggo16]

I have the same warning since several versions before.

[Krusheuski]

The same warning in the version 2.7.0.

[jpsim]

Yes, this is still a problem. I haven't found a reliable way to avoid it in all cases, however.

[redanula]

Mark. The problem still exists in 2.8.0. (Xcode 8.2.1 CocoaPods 1.2.1)

[jpsim]

Correct, this problem still exists, under certain compiler conditions with CocoaPods. If anyone has suggestions for a proper fix that works under all circumstances, please let me know

[Agoer]

The problem still exists in 2.10.0. Thanks!

[zhpengkun]

The problem still exists in 2.10.0.

[zingano]

Still happening in 2.10.1

[skensell]

Still happening in 2.10.2

[crontab]

Still happening in 3.0.2 when linking statically, though not when linking as a framework.