Respect existing environment variables in build tool plugins (#6566)

Author: SimplyDanny

CHANGELOG.md

@@ -72,6 +72,11 @@
   `redundant_self` rule.  
   [SimplyDanny](https://github.com/SimplyDanny)
   [#6553](https://github.com/realm/SwiftLint/issues/6553)
+  
+* Respect existing environment variables when setting `BUILD_WORKSPACE_DIRECTORY`
+  in build tool plugins.  
+  [SimplyDanny](https://github.com/SimplyDanny)
+  [#6080](https://github.com/realm/SwiftLint/issues/6080)
 
 ## 0.63.2: High-Speed Extraction
 

Plugins/SwiftLintBuildToolPlugin/SwiftLintBuildToolPlugin.swift

@@ -36,7 +36,7 @@ struct SwiftLintBuildToolPlugin: BuildToolPlugin {
         target: Target
     ) throws -> [String: String] {
         let workingDirectory: Path = try target.directory.resolveWorkingDirectory(in: context.package.directory)
-        return ["BUILD_WORKSPACE_DIRECTORY": "\(workingDirectory)"]
+        return addedToEnvironment(["BUILD_WORKSPACE_DIRECTORY": "\(workingDirectory)"])
     }
 
     private func makeCommand(
@@ -83,6 +83,10 @@ struct SwiftLintBuildToolPlugin: BuildToolPlugin {
     }
 }
 
+private func addedToEnvironment(_ new: [String: String]) -> [String: String] {
+    ProcessInfo.processInfo.environment.merging(new) { _, new in new }
+}
+
 #if canImport(XcodeProjectPlugin)
 
 import XcodeProjectPlugin
@@ -138,7 +142,7 @@ extension SwiftLintBuildToolPlugin: XcodeBuildToolPlugin {
             throw SwiftLintBuildToolPluginError.swiftFilesNotInWorkingDirectory(workingDirectory)
         }
 
-        return ["BUILD_WORKSPACE_DIRECTORY": "\(workingDirectory)"]
+        return addedToEnvironment(["BUILD_WORKSPACE_DIRECTORY": "\(workingDirectory)"])
     }
 }