Fix hang when merging stderr with stdout

Author: cmcgee1024

Sources/Subprocess/PipeConfiguration.swift

@@ -294,9 +294,7 @@ extension PipeConfiguration {
             group.addTask {
                 let errorReadFileDescriptor = createIODescriptor(from: sharedErrorPipe.readEnd, closeWhenDone: true)
                 let errorReadEnd = errorReadFileDescriptor.createIOChannel()
-
                 let stderr = try await self.error.captureOutput(from: errorReadEnd)
-
                 return .stderr(stderr)
             }
 
@@ -342,12 +340,10 @@ extension PipeConfiguration {
                                         let originalResult = try await Subprocess.run(
                                             configuration,
                                             input: self.input,
-                                            output: .fileDescriptor(writeEnd, closeAfterSpawningProcess: false),
+                                            output: .fileDescriptor(writeEnd, closeAfterSpawningProcess: true),
                                             error: .combineWithOutput
                                         )
 
-                                        try writeEnd.close()
-
                                         taskResult = PipelineTaskResult.success(
                                             0,
                                             SendableCollectedResult(
@@ -471,12 +467,10 @@ extension PipeConfiguration {
                                         let originalResult = try await Subprocess.run(
                                             configuration,
                                             input: .fileDescriptor(readEnd, closeAfterSpawningProcess: true),
-                                            output: .fileDescriptor(writeEnd, closeAfterSpawningProcess: false),
+                                            output: .fileDescriptor(writeEnd, closeAfterSpawningProcess: true),
                                             error: .combineWithOutput
                                         )
 
-                                        try writeEnd.close()
-
                                         taskResult = PipelineTaskResult.success(
                                             i,
                                             SendableCollectedResult(

Tests/SubprocessTests/PipeConfigurationTests.swift

@@ -30,6 +30,15 @@ func pipe(
     return [PipeStage(configuration: configurable.configuration, options: options)]
 }
 
+extension [PipeStage] {
+    func stage(
+        _ configurable: any Configurable,
+        options: ProcessStageOptions = .default
+    ) -> [PipeStage] {
+        return self.stage(configurable.configuration, options: options)
+    }
+}
+
 /// Pipe operator for stage arrays with Configuration
 func | (
     left: [PipeStage],
@@ -237,6 +246,8 @@ struct PipeConfigurationTests {
     @Test func testBasicPipeConfiguration() async throws {
         let config = pipe(
             Echo("Hello World")
+        ).stage(
+            Cat()
         ).finally(
             output: .string(limit: .max),
             error: .discarded
@@ -342,7 +353,7 @@ struct PipeConfigurationTests {
         let processConfig =
             pipe(
                 Echo("Test Message")
-            ) |> .string(limit: .max)
+            ) | Cat() |> .string(limit: .max)
 
         let result = try await processConfig.run()
         #expect(result.standardOutput?.trimmingCharacters(in: CharacterSet.whitespacesAndNewlines) == "Test Message")
@@ -868,19 +879,19 @@ struct PipeConfigurationTests {
                 .name("powershell.exe"),
                 arguments: Arguments(["-Command", "'shell stdout'; [Console]::Error.WriteLine('shell stderr')"]),
                 options: .mergeErrors
-            ) |> (
+            ) | Grep("shell") |> (
                 output: .string(limit: .max),
-                error: .string(limit: .max)
+                error: .discarded
             )
         #else
         let config =
             pipe(
                 .name("sh"),
                 arguments: ["-c", "echo 'shell stdout'; echo 'shell stderr' >&2"],
                 options: .mergeErrors
-            ) |> (
+            ) | Grep("shell") |> (
                 output: .string(limit: .max),
-                error: .string(limit: .max)
+                error: .discarded
             )
         #endif