Use `flat_map` instead of flatten in some cases

lib/cocoapods/installer.rb

@@ -219,8 +219,8 @@ module Pod
     #         generated as result of the analyzer.
     #
     def pod_targets
-      aggregate_target_pod_targets = aggregate_targets.map(&:pod_targets).flatten
-      test_dependent_targets = aggregate_target_pod_targets.map(&:test_dependent_targets).flatten
+      aggregate_target_pod_targets = aggregate_targets.flat_map(&:pod_targets)
+      test_dependent_targets = aggregate_target_pod_targets.flat_map(&:test_dependent_targets)
       (aggregate_target_pod_targets + test_dependent_targets).uniq
     end
 

lib/cocoapods/installer/analyzer.rb

@@ -340,7 +340,7 @@ module Pod
         end
 
         unless embedded_targets_missing_hosts.empty?
-          embedded_targets_missing_hosts_product_types = Set.new embedded_targets_missing_hosts.map(&:user_targets).flatten.map(&:symbol_type)
+          embedded_targets_missing_hosts_product_types = Set.new embedded_targets_missing_hosts.flat_map(&:user_targets).map(&:symbol_type)
           target_names = embedded_targets_missing_hosts.map do |target|
             target.name.sub('Pods-', '') # Make the target names more recognizable to the user
           end.join ', '

lib/cocoapods/installer/xcode/pods_project_generator/file_references_installer.rb

@@ -182,7 +182,7 @@ module Pod
           #         specs platform combinations.
           #
           def file_accessors
-            @file_accessors ||= pod_targets.map(&:file_accessors).flatten.compact
+            @file_accessors ||= pod_targets.flat_map(&:file_accessors).compact
           end
 
           # Adds file references to the list of the paths returned by the file

lib/cocoapods/installer/xcode/pods_project_generator/pod_target_integrator.rb

@@ -75,8 +75,8 @@ module Pod
             input_paths = []
             output_paths = []
             unless framework_paths.empty?
-              input_paths = [script_path, *framework_paths.map { |fw| [fw[:input_path], fw[:dsym_input_path]] }.flatten.compact]
-              output_paths = framework_paths.map { |fw| [fw[:output_path], fw[:dsym_output_path]] }.flatten.compact
+              input_paths = [script_path, *framework_paths.flat_map { |fw| [fw[:input_path], fw[:dsym_input_path]] }.compact]
+              output_paths = framework_paths.flat_map { |fw| [fw[:output_path], fw[:dsym_output_path]] }.compact
             end
             UserProjectIntegrator::TargetIntegrator.validate_input_output_path_limit(input_paths, output_paths)
             UserProjectIntegrator::TargetIntegrator.create_or_update_embed_frameworks_script_phase_to_target(native_target, script_path, input_paths, output_paths)
@@ -95,7 +95,7 @@ module Pod
           # @return [Array<Hash<Symbol=>String>] an array of all combined script phases from the specs.
           #
           def script_phases_for_specs(specs)
-            specs.map { |spec| spec.consumer(target.platform) }.map(&:script_phases).flatten
+            specs.flat_map { |spec| spec.consumer(target.platform).script_phases }
           end
         end
       end

lib/cocoapods/sandbox/file_accessor.rb

@@ -196,9 +196,9 @@ module Pod
       #         shipped with the Pod.
       #
       def vendored_frameworks_headers
-        vendored_frameworks.map do |framework|
+        vendored_frameworks.flat_map do |framework|
           self.class.vendored_frameworks_headers(framework)
-        end.flatten.uniq
+        end.uniq
       end
 
       # @return [Array<Pathname>] The paths of the library bundles that come

lib/cocoapods/target/aggregate_target.rb

@@ -162,7 +162,7 @@ module Pod
     # @return [Array<Specification>] The specifications used by this aggregate target.
     #
     def specs
-      pod_targets.map(&:specs).flatten
+      pod_targets.flat_map(&:specs)
     end
 
     # @return [Hash{Symbol => Array<Specification>}] The pod targets for each

spec/unit/installer/xcode/target_validator_spec.rb

@@ -28,7 +28,7 @@ module Pod
           result = @analyzer.analyze
 
           aggregate_targets = result.targets
-          pod_targets = aggregate_targets.map(&:pod_targets).flatten.uniq
+          pod_targets = aggregate_targets.flat_map(&:pod_targets).uniq
           sandbox.create_file_accessors(pod_targets)
 
           TargetValidator.new(aggregate_targets, pod_targets)