Support xcconfig file from plugin

[Fatme]

The .xcconfig file should be in platforms/ios folder of the plugin and will be included into native project's xcconfig file.

[jasssonpet]

It turns out that now the CocoaPods xcconfig overrides the default one and the build fails.

[jasssonpet]

I've moved the nativescript xcconfig to the project level, and Cocoapods uses the target xcconfig so everything should work now - NativeScript/ios-jsc#322

[jasssonpet]

At the moment there is an issue, that only one plugin with xcconfig is supported. This is because at a given level (target or project), only the last assignment of Xcode flags is preserved. The $(inherited) value works only for parent settings, not for previous ones.

This conflicts occur also not only between plugins with xcconfig files, but also with CocoaPods (which uses xcconfig files) and now with the iOS runtime also.

A possible solution is that we merge the build setting flags from all plugins in a single variable assignment. For example:

• plugin-1.xcconfig: OTHER_LDFLAGS -framework "CoreGraphics"
• plugin-2.xcconfig: OTHER_LDFLAGS -l"sqlite3"
• build.xcconfig: OTHER_LDFLAGS -framework "CoreGraphics" -l"sqlite3"

This is what CocoaPods is doing: https://guides.cocoapods.org/syntax/podspec.html#pod_target_xcconfig.

[jasssonpet]

After some more discussion with @fealebenpae we have a new proposal:

Instead of a xcconfig file, each plugin could have a .json file that looks something like:

{
  "OTHER_LDFLAGS": "-framework CoreGraphics"
}

This would make processing the file easier.

On prepare we should modify the application build.xcconfig to look like:

OTHER_LDFLAGS _<PLUGIN_NAME> = -framework CoreGraphics
OTHER_LDFLAGS = $(inherited) $(OTHER_LDFLAGS_<PLUGIN_NAME>)

The extra variable is in order to make removing plugins safely possible.

@Fatme I would appreciate hearing your thoughts on this.

[ligaz]

Isn't it better if we say that the only way to support this is via Cocoapods? If you have a plugin that requires compiler flag changes wrap it in a pod and give it to us.

[fealebenpae]

Does CocoaPods support binary-only pods? That is to say, if you only have a static library from a vendor, say TelerikUI, can you wrap that in a pod?

[ligaz]

It looks like this according to this issue. Also there is support for vendored_frameworks and vendored_libraries as mentioned in the Changelog.

[vchimev]

Issue 1:

VCHIMEVMAC:Work vchimev$ node_modules/.bin/tns plugin add plugin/xcconfig-plugin --path app123
npm WARN package.json @ No description
npm WARN package.json @ No repository field.
npm WARN package.json @ No README data
[email protected] app123/node_modules/xcconfig-plugin
Successfully installed plugin xcconfig-plugin.
VCHIMEVMAC:Work vchimev$ cat app123/package.json 
{
  "nativescript": {
    "id": "org.nativescript.app123",
    "tns-ios": {
      "version": "1.4.1"
    }
  },
  "dependencies": {
    "tns-core-modules": "1.4.0",
    "xcconfig-plugin": "file:plugin/xcconfig-plugin"
  }
}
VCHIMEVMAC:Work vchimev$ 
VCHIMEVMAC:Work vchimev$ 
VCHIMEVMAC:Work vchimev$ node_modules/.bin/tns run ios --path app123
Successfully prepared plugin xcconfig-plugin for ios.
Processing node_modules failed. Error:Error: EISDIR, read

Issue 2:
After adding plugin which contains Podfile and prepare the project, plugin-debug.xcconfig and plugin-release.xcconfig disappear.