Packages/ICCeryCore/Sources/ICCeryCore/Process/ProcessManager.swift

@@ -179,6 +179,14 @@ public actor ProcessManager {
 
         do {
             try process.run()
+            // Fallback watchdog: very fast child exits can race past the
+            // terminationHandler delivery on a loaded host. waitUntilExit()
+            // blocks the detached thread and guarantees didTerminate runs.
+            Task.detached { [weak self, process] in
+                process.waitUntilExit()
+                guard let self else { return }
+                await self.didTerminate(id: id, code: process.terminationStatus)
+            }
         } catch {
             preKillHooks.removeValue(forKey: id)
             children.removeValue(forKey: id)
@@ -273,6 +281,14 @@ public actor ProcessManager {
 
         do {
             try process.run()
+            // Fallback watchdog: very fast child exits can race past the
+            // terminationHandler delivery on a loaded host. waitUntilExit()
+            // blocks the detached thread and resumes the box if the handler
+            // did not already do so (#50, #52).
+            Task.detached { [capturedProcess] in
+                capturedProcess.waitUntilExit()
+                _ = box.resume(with: capturedProcess.terminationStatus)
+            }
         } catch {
             _ = box.resume(with: -1)
             captured.removeValue(forKey: id)

Sources/ICCery/TargetWorkflowViewModel.swift

@@ -109,6 +109,9 @@ final class TargetWorkflowViewModel {
     var printNotice: String?
     var printNoticeIsError = false
     var isPrinting = false
+    /// Strong reference to the active print task so the unstructured
+    /// `Task` is not dropped before it resumes.
+    private var printTask: Task<Void, Never>?
 
     // MARK: - Presets
 
@@ -480,7 +483,9 @@ final class TargetWorkflowViewModel {
     func printAllPages() {
         guard let result = printtargResult, !isPrinting else { return }
         isPrinting = true
-        Task { @MainActor in
+        let task = Task { @MainActor [weak self] in
+            guard let self else { return }
+            defer { self.printTask = nil }
             var printed = 0
             for page in result.pages {
                 do {
@@ -498,13 +503,16 @@ final class TargetWorkflowViewModel {
             printNoticeIsError = false
             isPrinting = false
         }
+        printTask = task
     }
 
     /// `#btnPrintPage-N` — one TIFF.
     func printPage(_ page: GalleryPage) {
         guard !isPrinting else { return }
         isPrinting = true
-        Task { @MainActor in
+        let task = Task { @MainActor [weak self] in
+            guard let self else { return }
+            defer { self.printTask = nil }
             do {
                 try await spool(page, index: page.index)
                 printNotice = "Sent \(page.page.filename) to \(selectedPrinter)."
@@ -515,6 +523,7 @@ final class TargetWorkflowViewModel {
             }
             isPrinting = false
         }
+        printTask = task
     }
 
     private func spool(_ page: GalleryPage, index: Int) async throws {

Tests/ICCeryCoreTests/ProcessManagerTests.swift

@@ -170,6 +170,24 @@ struct ProcessManagerTests {
         #expect(result.exitCode == 3)
     }
 
+    @Test func capturedRunFastExit() async throws {
+        let pm = ProcessManager()
+        let bin = try script("fast.sh", "#!/bin/sh\nexit 7\n")
+        let result = try await pm.runCaptured(id: "fast", binary: bin, arguments: [])
+        #expect(result.exitCode == 7)
+        #expect(result.stdout == "")
+        #expect(result.stderr == "")
+    }
+
+    @Test func capturedRunStderrOnly() async throws {
+        let pm = ProcessManager()
+        let bin = try script("stderr-only.sh", "#!/bin/sh\necho 'mock lp failure' 1>&2\nexit 1\n")
+        let result = try await pm.runCaptured(id: "stderr-only", binary: bin, arguments: [])
+        #expect(result.exitCode == 1)
+        #expect(result.stdout == "")
+        #expect(result.stderr.contains("mock lp failure"))
+    }
+
     @Test func capturedRunDoesNotDeadlockOnLargeOutput() async throws {
         let pm = ProcessManager()
         // 5000 lines each stream exceeds the 64 KiB pipe buffer.