Allow 'features' customization via 'user_options' (#192)

'features' provides a mechanism for customizing the Bazel toolchain
configuration:

docs.bazel.build/versions/main/cc-toolchain-config-reference.html

It's a useful knob to expose via PodToBUILD for those cases when you
want a library to opt-in to features like dead code stripping, dsym
generation, or other local toolchain features.

Author: jparise

BazelExtensions/workspace.bzl

@@ -256,7 +256,7 @@ def new_pod_repository(name,
          PlusEquals ( += ). Add an item to an array
 
          Implemented for:
-         `objc_library` [ `copts`, `deps`, `sdk_frameworks` ]
+         `objc_library` [ `copts`, `deps`, `features`, `sdk_frameworks` ]
 
          Example usage: add a custom define to the target, Texture's `copts`
          field

Examples/React/Podfile.lock

@@ -366,4 +366,4 @@ SPEC CHECKSUMS:
 
 PODFILE CHECKSUM: 2b89daabd5eca2c25b3d551f2e421e69a395664d
 
-COCOAPODS: 1.11.0
+COCOAPODS: 1.11.2

README.md

@@ -216,7 +216,7 @@ Supported operators:
 PlusEquals ( += ). Add an item to an array
 
 Implemented for:
-`objc_library`. Supported fields: `copts`, `deps`, `sdk_frameworks`
+`objc_library`. Supported fields: `copts`, `deps`, `features`, `sdk_frameworks`
 
 Example usage: add a custom define to the target, Texture's `copts`
 field

Sources/PodToBUILD/EmptyDepPruneTransform.swift

@@ -91,8 +91,8 @@ struct EmptyDepPruneTransform : SkylarkConvertibleTransform {
                                 lib.prefixHeader, includes: lib.includes,
                                 sdkFrameworks: lib.sdkFrameworks, weakSdkFrameworks:
                                 lib.weakSdkFrameworks, sdkDylibs: lib.sdkDylibs, deps:
-                                prunedDeps, copts: lib.copts, bundles: lib.bundles, resources:
-                                lib.resources, publicHeaders: lib.publicHeaders,
+                                prunedDeps, copts: lib.copts, features: lib.features, bundles:
+                                lib.bundles, resources: lib.resources, publicHeaders: lib.publicHeaders,
                                 nonArcSrcs: lib.nonArcSrcs, requiresArc:
                                 lib.requiresArc, isTopLevelTarget: lib.isTopLevelTarget)
 

Sources/PodToBUILD/ObjcLibrary.swift

@@ -147,6 +147,7 @@ public struct ObjcImport: BazelTarget {
 public enum ObjcLibraryConfigurableKeys : String {
     case copts
     case deps
+    case features
     case sdkFrameworks = "sdk_frameworks"
 }
 
@@ -173,6 +174,7 @@ public struct ObjcLibrary: BazelTarget, UserConfigurable, SourceExcludable {
     public var sdkFrameworks: AttrSet<[String]>
     public var copts: AttrSet<[String]>
     public var deps: AttrSet<[String]>
+    public var features: AttrSet<[String]>
 
     public let isTopLevelTarget: Bool
     public let externalName: String
@@ -191,6 +193,7 @@ public struct ObjcLibrary: BazelTarget, UserConfigurable, SourceExcludable {
         sdkDylibs: AttrSet<[String]> = AttrSet.empty,
         deps: AttrSet<[String]> = AttrSet.empty,
         copts: AttrSet<[String]> = AttrSet.empty,
+        features: AttrSet<[String]> = AttrSet.empty,
         bundles: AttrSet<[String]> = AttrSet.empty,
         resources: AttrSet<GlobNode> = AttrSet.empty,
         publicHeaders: AttrSet<GlobNode> = AttrSet.empty,
@@ -211,6 +214,7 @@ public struct ObjcLibrary: BazelTarget, UserConfigurable, SourceExcludable {
         self.sdkDylibs = sdkDylibs
         self.deps = deps
         self.copts = copts
+        self.features = features
         self.bundles = bundles
         self.resources = resources
         self.nonArcSrcs = nonArcSrcs
@@ -398,6 +402,8 @@ public struct ObjcLibrary: BazelTarget, UserConfigurable, SourceExcludable {
             AttrSet(basic: xcconfigCopts) <>
             fallbackSpec.attr(\.compilerFlags)
 
+        features = AttrSet.empty
+
         // Select resources that are not prebuilt bundles
         let resourceFiles = (spec.attr(\.resources).map { (strArr: [String]) -> [String] in
             strArr.filter { (str: String) -> Bool in
@@ -441,6 +447,10 @@ public struct ObjcLibrary: BazelTarget, UserConfigurable, SourceExcludable {
                 if let value = value as? String {
                     self.deps = self.deps <> AttrSet(basic: [value])
                 }
+            case .features:
+                if let value = value as? String {
+                    self.features = self.features <> AttrSet(basic: [value])
+                }
             }
 
         }
@@ -620,9 +630,9 @@ public struct ObjcLibrary: BazelTarget, UserConfigurable, SourceExcludable {
                         lib.prefixHeader, includes: lib.includes,
                         sdkFrameworks: lib.sdkFrameworks, weakSdkFrameworks:
                         lib.weakSdkFrameworks, sdkDylibs: lib.sdkDylibs, deps:
-                        deps, copts: lib.copts, bundles: lib.bundles, resources:
-                        lib.resources, publicHeaders: lib.publicHeaders,
-                        nonArcSrcs: nonArcSources, requiresArc:
+                        deps, copts: lib.copts, features: lib.features, bundles:
+                        lib.bundles, resources: lib.resources, publicHeaders:
+                        lib.publicHeaders, nonArcSrcs: nonArcSources, requiresArc:
                         lib.requiresArc, isTopLevelTarget: lib.isTopLevelTarget)
 
     }
@@ -891,6 +901,13 @@ public struct ObjcLibrary: BazelTarget, UserConfigurable, SourceExcludable {
             ))
         }
 
+        if !lib.features.isEmpty {
+            libArguments.append(.named(
+                name: "features",
+                value: lib.features.toSkylark()
+            ))
+        }
+
         let buildConfigDependenctCOpts: SkylarkNode =
             .functionCall(name: "select",
              arguments: [

Tests/BuildTests/Examples/React/Pods.WORKSPACE

@@ -73,7 +73,10 @@ new_pod_repository(
   podspec_url = "Vendor/PodSpecs/react-native-third-party-0.51.0/Folly.podspec",
   url = "https://github.com/facebook/folly/archive/v2016.09.26.00.zip",
   generate_module_map = False,
-  user_options = [ "folly.copts += -IVendor/Glog" ],
+  user_options = [
+    "folly.copts += -IVendor/Glog",
+    "folly.features += dead_strip",
+  ],
   install_script = """
     __INIT_REPO__
     # TODO: Why is the Podspec using this as a ModuleName, if Folly imports

bin/update_pods.py

@@ -392,7 +392,7 @@ def new_pod_repository(name,
          PlusEquals ( += ). Add an item to an array
 
          Implemented for:
-         `objc_library` [ `copts`, `deps`, `sdk_frameworks` ]
+         `objc_library` [ `copts`, `deps`, `features`, `sdk_frameworks` ]
 
          Example usage: add a custom define to the target, Texture's `copts`
          field