fix(shell-hook): pass the cd target through a file so prompts keep the TTY

cmd/navigate.go

@@ -2,19 +2,31 @@ package cmd
 
 import (
 	"fmt"
+	"os"
 	"path/filepath"
 
 	"github.com/amustafa/stackr/internal/engine"
 )
 
-// handleNavigateResult prints worktree cd markers or checkout confirmation.
-// The shell hook (sr shell-hook) parses __sr_cd: lines to trigger cd.
+// handleNavigateResult reports a worktree switch so the shell hook can cd.
+//
+// New hooks pass SR_CD_FILE, a scratch file to write the target into — a side
+// channel that exists so the hook never has to capture stdout (capturing
+// un-TTYs it, which disables every interactive prompt). The __sr_cd: sentinel
+// on stdout remains as the fallback for hooks eval'd before this change.
 func handleNavigateResult(result engine.NavigateResult) {
-	if result.IsWorktree() {
-		absPath := result.WorktreePath
-		if !filepath.IsAbs(absPath) {
-			absPath = filepath.Join(ctx.Git.Dir, absPath)
+	if !result.IsWorktree() {
+		return
+	}
+	absPath := result.WorktreePath
+	if !filepath.IsAbs(absPath) {
+		absPath = filepath.Join(ctx.Git.Dir, absPath)
+	}
+	if cdFile := os.Getenv("SR_CD_FILE"); cdFile != "" {
+		if err := os.WriteFile(cdFile, []byte(absPath+"\n"), 0o600); err == nil {
+			return
 		}
-		fmt.Printf("__sr_cd:%s\n", absPath)
+		// Couldn't write the file — fall through to the sentinel.
 	}
+	fmt.Printf("__sr_cd:%s\n", absPath)
 }

cmd/navigate_test.go

@@ -0,0 +1,99 @@
+package cmd
+
+import (
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/amustafa/stackr/internal/engine"
+)
+
+// captureStdout runs fn with os.Stdout redirected to a pipe and returns what
+// it wrote. Fine for these tests' few bytes; a writer that filled the pipe
+// buffer would deadlock.
+func captureStdout(t *testing.T, fn func()) string {
+	t.Helper()
+	old := os.Stdout
+	r, w, err := os.Pipe()
+	if err != nil {
+		t.Fatal(err)
+	}
+	os.Stdout = w
+
+	fn()
+
+	w.Close()
+	os.Stdout = old
+	out, err := io.ReadAll(r)
+	r.Close()
+	if err != nil {
+		t.Fatal(err)
+	}
+	return string(out)
+}
+
+func TestHandleNavigateResult_WritesCdFileInsteadOfSentinel(t *testing.T) {
+	cdFile := filepath.Join(t.TempDir(), "cd-target")
+	t.Setenv("SR_CD_FILE", cdFile)
+
+	target := t.TempDir()
+	out := captureStdout(t, func() {
+		handleNavigateResult(engine.NavigateResult{Branch: "b", WorktreePath: target})
+	})
+
+	data, err := os.ReadFile(cdFile)
+	if err != nil {
+		t.Fatalf("cd file was not written: %v", err)
+	}
+	if got := strings.TrimSpace(string(data)); got != target {
+		t.Fatalf("cd file holds %q, want %q", got, target)
+	}
+	if strings.Contains(out, "__sr_cd:") {
+		t.Fatalf("sentinel must not be printed when SR_CD_FILE is honored; stdout: %q", out)
+	}
+}
+
+func TestHandleNavigateResult_FallsBackToSentinelWithoutEnv(t *testing.T) {
+	t.Setenv("SR_CD_FILE", "")
+	os.Unsetenv("SR_CD_FILE")
+
+	target := t.TempDir()
+	out := captureStdout(t, func() {
+		handleNavigateResult(engine.NavigateResult{Branch: "b", WorktreePath: target})
+	})
+
+	if want := "__sr_cd:" + target; !strings.Contains(out, want) {
+		t.Fatalf("old hooks rely on the sentinel; stdout %q lacks %q", out, want)
+	}
+}
+
+func TestHandleNavigateResult_FallsBackWhenCdFileUnwritable(t *testing.T) {
+	t.Setenv("SR_CD_FILE", filepath.Join(t.TempDir(), "no", "such", "dir", "f"))
+
+	target := t.TempDir()
+	out := captureStdout(t, func() {
+		handleNavigateResult(engine.NavigateResult{Branch: "b", WorktreePath: target})
+	})
+
+	if want := "__sr_cd:" + target; !strings.Contains(out, want) {
+		t.Fatalf("an unwritable cd file must fall back to the sentinel; stdout: %q", out)
+	}
+}
+
+func TestHandleNavigateResult_PlainCheckoutPrintsNothing(t *testing.T) {
+	cdFile := filepath.Join(t.TempDir(), "cd-target")
+	t.Setenv("SR_CD_FILE", cdFile)
+
+	out := captureStdout(t, func() {
+		handleNavigateResult(engine.NavigateResult{Branch: "b"})
+	})
+
+	if out != "" {
+		t.Fatalf("non-worktree navigation should print nothing, got %q", out)
+	}
+	if _, err := os.Stat(cdFile); !os.IsNotExist(err) {
+		t.Fatalf("non-worktree navigation must not write the cd file")
+	}
+}

cmd/shell_hook.go

@@ -6,39 +6,34 @@ import (
 	"github.com/spf13/cobra"
 )
 
+// The hook must not capture sr's stdout: command substitution turns stdout
+// into a pipe, root's TTY check then classifies the run as non-interactive,
+// and every prompt silently takes its scripted branch. The cd target instead
+// travels through a scratch file named in SR_CD_FILE, leaving stdin/stdout
+// attached to the terminal.
 const shellHookScript = `
 sr() {
-  local output
-  output="$(command sr "$@")"
-  local exit_code=$?
-
-  local cd_target=""
-  local rest=""
-  while IFS= read -r line; do
-    case "$line" in
-      __sr_cd:*)
-        cd_target="${line#__sr_cd:}"
-        ;;
-      *)
-        if [ -n "$rest" ]; then
-          rest="$rest
-$line"
-        else
-          rest="$line"
-        fi
-        ;;
-    esac
-  done <<< "$output"
-
-  if [ -n "$rest" ]; then
-    printf '%s\n' "$rest"
+  local cd_file exit_code
+  cd_file="$(mktemp "${TMPDIR:-/tmp}/sr-cd.XXXXXX")" || {
+    command sr "$@"
+    return $?
+  }
+
+  SR_CD_FILE="$cd_file" command sr "$@"
+  exit_code=$?
+
+  if [ -s "$cd_file" ]; then
+    local cd_target=""
+    IFS= read -r cd_target < "$cd_file"
+    if [ -n "$cd_target" ] && [ -d "$cd_target" ]; then
+      if cd "$cd_target"; then
+        printf 'Switched to worktree at %s\n' "$cd_target"
+      else
+        exit_code=1
+      fi
+    fi
   fi
-
-  if [ -n "$cd_target" ]; then
-    cd "$cd_target" || return 1
-    printf 'Switched to worktree at %s\n' "$cd_target"
-  fi
-
+  rm -f "$cd_file"
   return $exit_code
 }
 `
@@ -49,6 +44,10 @@ var shellHookCmd = &cobra.Command{
 	Long: `Print a shell function that wraps sr to enable automatic directory
 changes when navigating to branches in worktrees.
 
+The function passes sr a scratch file (SR_CD_FILE) to receive the cd target,
+so sr's stdin/stdout stay attached to the terminal and interactive prompts
+keep working.
+
 Add this to your shell rc file (.bashrc or .zshrc):
 
   eval "$(sr shell-hook)"`,