From e102a0417a51afbf79f2edb05348b5a70fa3c456 Mon Sep 17 00:00:00 2001
From: Sami Suteria <sami.suteria@gmail.com>
Date: Tue, 14 Feb 2023 07:19:49 -0800
Subject: [PATCH] Add import paths to SPM Plugin (#1373)

* add import paths to config

* add comment

* Update Plugins/SwiftProtobufPlugin/plugin.swift

Co-authored-by: Franz Busch <privat@franz-busch.de>

* always include target.directory in import paths

---------

Co-authored-by: Franz Busch <privat@franz-busch.de>
---
 Plugins/SwiftProtobufPlugin/plugin.swift | 27 +++++++++++++++++++-----
 1 file changed, 22 insertions(+), 5 deletions(-)

diff --git a/Plugins/SwiftProtobufPlugin/plugin.swift b/Plugins/SwiftProtobufPlugin/plugin.swift
index 85bc30ea9..eb621549a 100644
--- a/Plugins/SwiftProtobufPlugin/plugin.swift
+++ b/Plugins/SwiftProtobufPlugin/plugin.swift
@@ -64,6 +64,13 @@ struct SwiftProtobufPlugin: BuildToolPlugin {
             var fileNaming: FileNaming?
         }
 
+        /// Specify the directory in which to search for
+        /// imports.  May be specified multiple times;
+        /// directories will be searched in order.
+        /// The target source directory is always appended
+        /// to the import paths.
+        var importPaths: [String]?
+
         /// The path to the `protoc` binary.
         ///
         /// If this is not set, SPM will try to find the tool itself.
@@ -88,6 +95,11 @@ struct SwiftProtobufPlugin: BuildToolPlugin {
 
         try validateConfiguration(configuration)
 
+        var importPaths: [Path] = [target.directory]
+        if let configuredImportPaths = configuration.importPaths {
+            importPaths.append(contentsOf: configuredImportPaths.map { Path($0) })
+        }
+
         // We need to find the path of protoc and protoc-gen-swift
         let protocPath: Path
         if let configuredProtocPath = configuration.protocPath {
@@ -111,7 +123,8 @@ struct SwiftProtobufPlugin: BuildToolPlugin {
                 invocation: invocation,
                 protocPath: protocPath,
                 protocGenSwiftPath: protocGenSwiftPath,
-                outputDirectory: outputDirectory
+                outputDirectory: outputDirectory,
+                importPaths: importPaths
             )
         }
     }
@@ -124,23 +137,27 @@ struct SwiftProtobufPlugin: BuildToolPlugin {
     ///   - protocPath: The path to the `protoc` binary.
     ///   - protocGenSwiftPath: The path to the `protoc-gen-swift` binary.
     ///   - outputDirectory: The output directory for the generated files.
+    ///   - importPaths: List of paths to pass with "-I <path>" to `protoc`
     /// - Returns: The build command.
     private func invokeProtoc(
         target: Target,
         invocation: Configuration.Invocation,
         protocPath: Path,
         protocGenSwiftPath: Path,
-        outputDirectory: Path
+        outputDirectory: Path,
+        importPaths: [Path]
     ) -> Command {
         // Construct the `protoc` arguments.
         var protocArgs = [
             "--plugin=protoc-gen-swift=\(protocGenSwiftPath)",
             "--swift_out=\(outputDirectory)",
-            // We include the target directory as a proto search path
-            "-I",
-            "\(target.directory)",
         ]
 
+        importPaths.forEach { path in
+            protocArgs.append("-I")
+            protocArgs.append("\(path)")
+        }
+
         // Add the visibility if it was set
         if let visibility = invocation.visibility {
             protocArgs.append("--swift_opt=Visibility=\(visibility.rawValue)")