wip: add synchronized output to prevent prompt interleaving

- Add SyncWriter to synchronize stdout/stderr writes with prompts
- Add promptMutex to serialize interactive prompts
- Keep rawStdout/rawStderr for BubbleTea to avoid deadlock
- Update test Taskfile with nested deps scenario

executor.go

@@ -54,9 +54,11 @@ type (
 		Failfast            bool
 
 		// I/O
-		Stdin  io.Reader
+		Stdin     io.Reader
-		Stdout io.Writer
+		Stdout    io.Writer
-		Stderr io.Writer
+		Stderr    io.Writer
+		rawStdout io.Writer // unwrapped stdout for prompts
+		rawStderr io.Writer // unwrapped stderr for prompts
 
 		// Internal
 		Taskfile           *ast.Taskfile
@@ -71,6 +73,7 @@ type (
 		fuzzyModel     *fuzzy.Model
 		fuzzyModelOnce sync.Once
 
+		promptMutex          sync.Mutex
 		concurrencySemaphore chan struct{}
 		taskCallCount        map[string]*int32
 		mkdirMutexMap        map[string]*sync.Mutex

internal/output/sync_writer.go

@@ -0,0 +1,28 @@
+package output
+
+import (
+	"io"
+	"sync"
+)
+
+// SyncWriter wraps an io.Writer with a mutex to synchronize writes.
+// This is used to prevent output from interleaving with interactive prompts.
+type SyncWriter struct {
+	w  io.Writer
+	mu *sync.Mutex
+}
+
+// NewSyncWriter creates a new SyncWriter that uses the provided mutex.
+func NewSyncWriter(w io.Writer, mu *sync.Mutex) *SyncWriter {
+	return &SyncWriter{
+		w:  w,
+		mu: mu,
+	}
+}
+
+// Write implements io.Writer with synchronized access.
+func (sw *SyncWriter) Write(p []byte) (n int, err error) {
+	sw.mu.Lock()
+	defer sw.mu.Unlock()
+	return sw.w.Write(p)
+}

requires.go

@@ -27,7 +27,16 @@ func (e *Executor) promptForInteractiveVars(t *ast.Task, call *Call) (bool, erro
 		return false, nil
 	}
 
-	prompter := prompt.New()
+	// Lock to prevent multiple parallel prompts from interleaving
+	e.promptMutex.Lock()
+	defer e.promptMutex.Unlock()
+
+	// Use raw stderr for prompts to avoid deadlock with SyncWriter
+	prompter := &prompt.Prompter{
+		Stdin:  e.Stdin,
+		Stdout: e.rawStdout,
+		Stderr: e.rawStderr,
+	}
 	var prompted bool
 
 	for _, requiredVar := range t.Requires.Vars {

setup.go

@@ -179,6 +179,17 @@ func (e *Executor) setupStdFiles() {
 	if e.Stderr == nil {
 		e.Stderr = os.Stderr
 	}
+
+	// Keep raw references for interactive prompts
+	e.rawStdout = e.Stdout
+	e.rawStderr = e.Stderr
+
+	// Wrap with synchronized writers when interactive mode is enabled
+	// to prevent output from interleaving with prompts
+	if e.Interactive {
+		e.Stdout = output.NewSyncWriter(e.Stdout, &e.promptMutex)
+		e.Stderr = output.NewSyncWriter(e.Stderr, &e.promptMutex)
+	}
 }
 
 func (e *Executor) setupLogger() {

testdata/interactive_vars/.taskrc.yml

@@ -0,0 +1 @@
+interactive: true

testdata/interactive_vars/Taskfile.yml

@@ -1,25 +1,66 @@
 version: "3"
 
 tasks:
-  simple:
+  main:
-    requires:
+    desc: Main task with nested deps
-      vars:
+    deps:
-        - MY_VAR
+      - dep-a
+      - dep-b
     cmds:
-      - echo "{{.MY_VAR}}"
+      - echo "Main task done!"
 
-  with-enum:
+  dep-a:
-    requires:
+    desc: Dependency A
-      vars:
+    deps:
-        - name: ENV
+      - leaf-a1
-          enum: [dev, staging, prod]
+      - leaf-a2
     cmds:
-      - echo "{{.ENV}}"
+      - echo "Dep A done"
 
-  multiple:
+  dep-b:
+    desc: Dependency B
+    deps:
+      - leaf-b1
+      - leaf-b2
+    cmds:
+      - echo "Dep B done"
+
+  leaf-a1:
+    desc: Leaf A1 with enum
     requires:
       vars:
-        - VAR1
+        - name: VAR_A1
-        - VAR2
+          enum:
+            - alpha
+            - beta
+            - gamma
     cmds:
-      - echo "{{.VAR1}} {{.VAR2}}"
+      - echo "Leaf A1 {{.VAR_A1}}"
+
+  leaf-a2:
+    desc: Leaf A2 with text
+    requires:
+      vars:
+        - VAR_A2
+    cmds:
+      - echo "Leaf A2 {{.VAR_A2}}"
+
+  leaf-b1:
+    desc: Leaf B1 with enum
+    requires:
+      vars:
+        - name: VAR_B1
+          enum:
+            - one
+            - two
+            - three
+    cmds:
+      - echo "Leaf B1 {{.VAR_B1}}"
+
+  leaf-b2:
+    desc: Leaf B2 with text
+    requires:
+      vars:
+        - VAR_B2
+    cmds:
+      - echo "Leaf B2 {{.VAR_B2}}"