fix(shell): prevent duplicate fnm multishell entries in PATH

integration/shell/adapter.go

@@ -67,10 +67,52 @@ func Init(name string) {
 // BashAdapter implementation
 type BashAdapter struct{}
 
+// clean child environment to avoid duplicate multishell entries and deduplicate path
+func CleanChildEnv(envList []string, fd int, pid int) []string {
+	multishell := os.Getenv("FNM_MULTISHELL_PATH")
+	if multishell != "" {
+		_ = os.RemoveAll(multishell)
+		_ = os.RemoveAll(filepath.Dir(multishell))
+	}
+
+	var res []string
+	for _, env := range envList {
+		key, val, ok := strings.Cut(env, "=")
+		if !ok {
+			continue
+		}
+		if key == "FNM_MULTISHELL_PATH" {
+			continue
+		}
+		if key == "PATH" {
+			entries := filepath.SplitList(val)
+			seen := make(map[string]bool, len(entries))
+			var clean []string
+			for _, entry := range entries {
+				if entry == "" {
+					continue
+				}
+				if strings.Contains(entry, "fnm_multishells") || (multishell != "" && (entry == multishell || entry == filepath.Join(multishell, "bin"))) {
+					continue
+				}
+				if !seen[entry] {
+					seen[entry] = true
+					clean = append(clean, entry)
+				}
+			}
+			res = append(res, "PATH="+strings.Join(clean, string(os.PathListSeparator)))
+			continue
+		}
+		res = append(res, env)
+	}
+
+	return append(res, "IRIS_FD="+fmt.Sprint(fd), "IRIS_PID="+fmt.Sprint(pid))
+}
+
 func (b *BashAdapter) GetName() string      { return "bash" }
 func (b *BashAdapter) GetShellPath() string { return "bash" }
 func (b *BashAdapter) GetEnv(fd int, pid int) []string {
-	return append(os.Environ(), "IRIS_FD="+fmt.Sprint(fd), "IRIS_PID="+fmt.Sprint(pid))
+	return CleanChildEnv(os.Environ(), fd, pid)
 }
 func (b *BashAdapter) PrepareSelectSequence(selected string, cursorFromEnd int) []byte {
 	return ReplaceLine([]byte(selected), cursorFromEnd)
@@ -85,7 +127,7 @@ type ZshAdapter struct{}
 func (z *ZshAdapter) GetName() string      { return "zsh" }
 func (z *ZshAdapter) GetShellPath() string { return "zsh" }
 func (z *ZshAdapter) GetEnv(fd int, pid int) []string {
-	return append(os.Environ(), "IRIS_FD="+fmt.Sprint(fd), "IRIS_PID="+fmt.Sprint(pid))
+	return CleanChildEnv(os.Environ(), fd, pid)
 }
 func (z *ZshAdapter) PrepareSelectSequence(selected string, cursorFromEnd int) []byte {
 	return ReplaceLine([]byte(selected), cursorFromEnd)
@@ -145,7 +187,7 @@ type FishAdapter struct{}
 func (f *FishAdapter) GetName() string      { return "fish" }
 func (f *FishAdapter) GetShellPath() string { return "fish" }
 func (f *FishAdapter) GetEnv(fd int, pid int) []string {
-	return append(os.Environ(), "IRIS_FD="+fmt.Sprint(fd), "IRIS_PID="+fmt.Sprint(pid))
+	return CleanChildEnv(os.Environ(), fd, pid)
 }
 func (f *FishAdapter) PrepareSelectSequence(selected string, cursorFromEnd int) []byte {
 	return ReplaceLine([]byte(selected), cursorFromEnd)

integration/shell/adapter_test.go

@@ -243,3 +243,44 @@ func TestPrepareSelectSequenceUsesReplaceLine(t *testing.T) {
 		}
 	}
 }
+
+func TestCleanChildEnv(t *testing.T) {
+	inputEnv := []string{
+		"USER=test",
+		"FNM_MULTISHELL_PATH=/Users/user/.local/state/fnm_multishells/5487_123/bin",
+		"PATH=/Users/user/.local/state/fnm_multishells/5487_123/bin:/usr/local/bin:/usr/bin:/bin:/usr/local/bin",
+	}
+
+	got := CleanChildEnv(inputEnv, 13, 9999)
+
+	var hasFnmVar bool
+	var pathVal string
+	var hasFd, hasPid bool
+
+	for _, e := range got {
+		if e == "FNM_MULTISHELL_PATH" || len(e) > 19 && e[:19] == "FNM_MULTISHELL_PATH=" {
+			hasFnmVar = true
+		}
+		if len(e) > 5 && e[:5] == "PATH=" {
+			pathVal = e[5:]
+		}
+		if e == "IRIS_FD=13" {
+			hasFd = true
+		}
+		if e == "IRIS_PID=9999" {
+			hasPid = true
+		}
+	}
+
+	if hasFnmVar {
+		t.Errorf("CleanChildEnv must unset FNM_MULTISHELL_PATH, got: %v", got)
+	}
+	if !hasFd || !hasPid {
+		t.Errorf("CleanChildEnv must include IRIS_FD=13 and IRIS_PID=9999, got: %v", got)
+	}
+	wantPath := "/usr/local/bin:/usr/bin:/bin"
+	if pathVal != wantPath {
+		t.Errorf("CleanChildEnv PATH = %q; want %q", pathVal, wantPath)
+	}
+}
+

root/init.go

@@ -35,6 +35,10 @@ fi
 # prompt to complete, and exec'ing here would seize the tty from the real iris
 if [[ -o interactive ]] && [ -t 0 ] && [ -z "$IRIS_PID" ] && [ -z "$IRIS_RESCUE" ]; then
     export IRIS_ACTIVE_SHELL="zsh"
+    if [ -n "$FNM_MULTISHELL_PATH" ]; then
+        path=(${path:#*fnm_multishells*})
+        unset FNM_MULTISHELL_PATH
+    fi
     exec iris
 fi
 
@@ -82,6 +86,15 @@ fi
 # prompt to complete, and exec'ing here would seize the tty from the real iris
 if [[ $- == *i* ]] && [ -t 0 ] && [ -z "$IRIS_PID" ] && [ -z "$IRIS_RESCUE" ]; then
     export IRIS_ACTIVE_SHELL="bash"
+    if [ -n "$FNM_MULTISHELL_PATH" ]; then
+        PATH=":$PATH:"
+        PATH="${PATH//:$FNM_MULTISHELL_PATH\/bin:/:}"
+        PATH="${PATH//:$FNM_MULTISHELL_PATH:/:}"
+        PATH="${PATH#:}"
+        PATH="${PATH%%:}"
+        export PATH
+        unset FNM_MULTISHELL_PATH
+    fi
     exec iris
 fi
 
@@ -123,6 +136,10 @@ end
 
 if status is-interactive; and not set -q IRIS_PID; and not set -q IRIS_RESCUE
     set -gx IRIS_ACTIVE_SHELL "fish"
+    if set -q FNM_MULTISHELL_PATH
+        set -gx PATH (string match -v "*fnm_multishells*" $PATH)
+        set -e FNM_MULTISHELL_PATH
+    end
     exec iris
 end
 

tests/tui/fnm_test.go

@@ -0,0 +1,194 @@
+package tui
+
+import (
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/Gaurav-Gosain/tuitest"
+)
+
+func TestFnmMultishellNotDuplicatedInPath(t *testing.T) {
+	if _, err := exec.LookPath("zsh"); err != nil {
+		t.Skip("zsh not installed")
+	}
+
+	home := t.TempDir()
+	for _, sub := range []string{".config/iris", ".local/share/iris", ".cache"} {
+		if err := os.MkdirAll(filepath.Join(home, sub), 0o755); err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	bin := binary(t)
+
+	outerFnmPath := filepath.Join(home, ".local/state/fnm_multishells/5487_outer/bin")
+	innerFnmPath := filepath.Join(home, ".local/state/fnm_multishells/5450_inner/bin")
+	_ = os.MkdirAll(outerFnmPath, 0o755)
+	_ = os.MkdirAll(innerFnmPath, 0o755)
+
+	// simulate .zshrc where fnm runs before iris init
+	zshrc := `
+PROMPT='> '
+RPROMPT=''
+unsetopt PROMPT_SP
+if [ -z "$IRIS_PID" ]; then
+    export FNM_MULTISHELL_PATH="` + outerFnmPath + `"
+    export PATH="$FNM_MULTISHELL_PATH:$PATH"
+fi
+eval "$(` + bin + ` init zsh)"
+if [ -n "$IRIS_PID" ]; then
+    export FNM_MULTISHELL_PATH="` + innerFnmPath + `"
+    export PATH="$FNM_MULTISHELL_PATH:$PATH"
+fi
+`
+	if err := os.WriteFile(filepath.Join(home, ".zshrc"), []byte(zshrc), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	env := []string{
+		"HOME=" + home,
+		"ZDOTDIR=" + home,
+		"XDG_CONFIG_HOME=" + filepath.Join(home, ".config"),
+		"XDG_DATA_HOME=" + filepath.Join(home, ".local/share"),
+		"XDG_CACHE_HOME=" + filepath.Join(home, ".cache"),
+		"SHELL=/bin/zsh",
+		"IRIS_ACTIVE_SHELL=zsh",
+		"PATH=" + os.Getenv("PATH"),
+		"TERM=xterm-256color",
+	}
+
+	term := tuitest.StartT(t, []string{bin},
+		tuitest.WithSize(cols, rows),
+		tuitest.WithEnv(env...),
+		tuitest.WithDir(home),
+	)
+	defer func() { _ = term.Close() }()
+
+	if err := term.WaitForText(">", 20*time.Second); err != nil {
+		t.Fatalf("iris never reached a prompt: %v\n%s", err, term.Snapshot())
+	}
+
+	outLog := filepath.Join(home, "path_out.txt")
+	cmd := "echo $PATH > " + outLog + "\n"
+	if err := term.SendKeys(cmd); err != nil {
+		t.Fatal(err)
+	}
+
+	// wait for path dump file to be written by the shell
+	var writtenPath string
+	for range 20 {
+		time.Sleep(100 * time.Millisecond)
+		data, err := os.ReadFile(outLog)
+		if err == nil && len(data) > 0 {
+			writtenPath = string(data)
+			break
+		}
+	}
+
+	if writtenPath == "" {
+		t.Fatalf("path file was not written, screen:\n%s", screen(term))
+	}
+
+	if strings.Contains(writtenPath, "5487_outer") {
+		t.Fatalf("PATH should not contain dead outer fnm multishell (5487_outer), got:\n%s", writtenPath)
+	}
+	if !strings.Contains(writtenPath, "5450_inner") {
+		t.Fatalf("PATH must contain active inner fnm multishell (5450_inner), got:\n%s", writtenPath)
+	}
+}
+
+func TestRealFnmWithIris(t *testing.T) {
+	if _, err := exec.LookPath("zsh"); err != nil {
+		t.Skip("zsh not installed")
+	}
+
+	fnmBin := "/tmp/fnm-bin/fnm"
+	if _, err := os.Stat(fnmBin); err != nil {
+		if path, errLook := exec.LookPath("fnm"); errLook == nil {
+			fnmBin = path
+		} else {
+			t.Skip("fnm binary not available")
+		}
+	}
+
+	home := t.TempDir()
+	for _, sub := range []string{".config/iris", ".local/share/iris", ".cache"} {
+		if err := os.MkdirAll(filepath.Join(home, sub), 0o755); err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	bin := binary(t)
+
+	// exact reproduction steps from issue #170
+	zshrc := `
+PROMPT='> '
+RPROMPT=''
+unsetopt PROMPT_SP
+eval "$(` + fnmBin + ` env --use-on-cd --shell zsh)"
+eval "$(` + bin + ` init zsh)"
+`
+	if err := os.WriteFile(filepath.Join(home, ".zshrc"), []byte(zshrc), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	env := []string{
+		"HOME=" + home,
+		"ZDOTDIR=" + home,
+		"XDG_CONFIG_HOME=" + filepath.Join(home, ".config"),
+		"XDG_DATA_HOME=" + filepath.Join(home, ".local/share"),
+		"XDG_CACHE_HOME=" + filepath.Join(home, ".cache"),
+		"SHELL=/bin/zsh",
+		"IRIS_ACTIVE_SHELL=zsh",
+		"PATH=" + os.Getenv("PATH"),
+		"TERM=xterm-256color",
+	}
+
+	term := tuitest.StartT(t, []string{bin},
+		tuitest.WithSize(cols, rows),
+		tuitest.WithEnv(env...),
+		tuitest.WithDir(home),
+	)
+	defer func() { _ = term.Close() }()
+
+	if err := term.WaitForText(">", 20*time.Second); err != nil {
+		t.Fatalf("iris never reached a prompt: %v\n%s", err, term.Snapshot())
+	}
+
+	outLog := filepath.Join(home, "path_out.txt")
+	cmd := "echo $PATH > " + outLog + "\n"
+	if err := term.SendKeys(cmd); err != nil {
+		t.Fatal(err)
+	}
+
+	var writtenPath string
+	for range 20 {
+		time.Sleep(100 * time.Millisecond)
+		data, err := os.ReadFile(outLog)
+		if err == nil && len(data) > 0 {
+			writtenPath = string(data)
+			break
+		}
+	}
+
+	if writtenPath == "" {
+		t.Fatalf("path file was not written, screen:\n%s", screen(term))
+	}
+
+	parts := strings.Split(strings.TrimSpace(writtenPath), ":")
+	fnmCount := 0
+	for _, p := range parts {
+		if strings.Contains(p, "fnm_multishells") {
+			fnmCount++
+		}
+	}
+
+	if fnmCount != 1 {
+		t.Fatalf("expected exactly 1 fnm_multishells entry in PATH, got %d:\n%s", fnmCount, writtenPath)
+	}
+}
+