refactor (shell) : Windows Shell detection uses gopsutil (#4588)

+ Update `shell_windows.go` to use detectShellByCheckingProcessTree
instead of relying on SHELL environment variable.
+ Remove hardcoded check from detectShellByCheckingProcessTree for shell
  types, use already present supportedShell slice.

Signed-off-by: Rohan Kumar <[email protected]>

Author: rohanKanojia

pkg/os/shell/shell.go

@@ -4,6 +4,7 @@ import (
 	"errors"
 	"fmt"
 	"os"
+	"slices"
 	"strings"
 
 	"github.com/shirou/gopsutil/v4/process"
@@ -208,7 +209,9 @@ func detectShellByCheckingProcessTree(p AbstractProcess) string {
 		if err != nil {
 			return ""
 		}
-		if processName == "zsh" || processName == "bash" || processName == "fish" {
+		if slices.ContainsFunc(supportedShell, func(listElem string) bool {
+			return strings.HasPrefix(processName, listElem)
+		}) {
 			return processName
 		}
 		p, err = p.Parent()

pkg/os/shell/shell_unix.go

@@ -8,6 +8,10 @@ import (
 	"path/filepath"
 )
 
+var (
+	supportedShell = []string{"bash", "zsh", "fish"}
+)
+
 // detect detects user's current shell.
 func detect() (string, error) {
 	detectedShell := detectShellByCheckingProcessTree(currentProcessSupplier())

pkg/os/shell/shell_windows.go

@@ -1,64 +1,18 @@
 package shell
 
 import (
-	"fmt"
-	"math"
-	"os"
-	"path/filepath"
+	"slices"
 	"sort"
 	"strconv"
 	"strings"
-	"syscall"
-	"unsafe"
 
 	"github.com/crc-org/crc/v2/pkg/crc/logging"
 )
 
 var (
-	supportedShell = []string{"cmd", "powershell", "bash", "zsh", "fish"}
+	supportedShell = []string{"cmd", "powershell", "wsl", "bash", "zsh", "fish"}
 )
 
-// re-implementation of private function in https://github.com/golang/go/blob/master/src/syscall/syscall_windows.go
-func getProcessEntry(pid uint32) (pe *syscall.ProcessEntry32, err error) {
-	snapshot, err := syscall.CreateToolhelp32Snapshot(syscall.TH32CS_SNAPPROCESS, 0)
-	if err != nil {
-		return nil, err
-	}
-	defer func() {
-		_ = syscall.CloseHandle(syscall.Handle(snapshot))
-	}()
-
-	var processEntry syscall.ProcessEntry32
-	processEntry.Size = uint32(unsafe.Sizeof(processEntry))
-	err = syscall.Process32First(snapshot, &processEntry)
-	if err != nil {
-		return nil, err
-	}
-
-	for {
-		if processEntry.ProcessID == pid {
-			pe = &processEntry
-			return
-		}
-
-		err = syscall.Process32Next(snapshot, &processEntry)
-		if err != nil {
-			return nil, err
-		}
-	}
-}
-
-// getNameAndItsPpid returns the exe file name its parent process id.
-func getNameAndItsPpid(pid uint32) (exefile string, parentid uint32, err error) {
-	pe, err := getProcessEntry(pid)
-	if err != nil {
-		return "", 0, err
-	}
-
-	name := syscall.UTF16ToString(pe.ExeFile[:])
-	return name, pe.ParentProcessID, nil
-}
-
 func shellType(shell string, defaultShell string) string {
 	switch {
 	case strings.Contains(strings.ToLower(shell), "powershell"):
@@ -69,39 +23,15 @@ func shellType(shell string, defaultShell string) string {
 		return "cmd"
 	case strings.Contains(strings.ToLower(shell), "wsl"):
 		return detectShellByInvokingCommand("bash", "wsl", []string{"-e", "bash", "-c", "ps -ao pid=,comm="})
-	case filepath.IsAbs(shell) && strings.Contains(strings.ToLower(shell), "bash"):
+	case strings.Contains(strings.ToLower(shell), "bash"):
 		return "bash"
 	default:
 		return defaultShell
 	}
 }
 
 func detect() (string, error) {
-	shell := os.Getenv("SHELL")
-
-	if shell == "" {
-		pid := os.Getppid()
-		if pid < 0 || pid > math.MaxUint32 {
-			return "", fmt.Errorf("integer overflow for pid: %v", pid)
-		}
-		shell, shellppid, err := getNameAndItsPpid(uint32(pid))
-		if err != nil {
-			return "cmd", err // defaulting to cmd
-		}
-		shell = shellType(shell, "")
-		if shell == "" {
-			shell, _, err := getNameAndItsPpid(shellppid)
-			if err != nil {
-				return "cmd", err // defaulting to cmd
-			}
-			return shellType(shell, "cmd"), nil
-		}
-		return shell, nil
-	}
-
-	if os.Getenv("__fish_bin_dir") != "" {
-		return "fish", nil
-	}
+	shell := detectShellByCheckingProcessTree(currentProcessSupplier())
 
 	return shellType(shell, "cmd"), nil
 }
@@ -163,9 +93,9 @@ func inspectProcessOutputForRecentlyUsedShell(psCommandOutput string) string {
 	lines := strings.Split(psCommandOutput, "\n")
 	for _, line := range lines {
 		lineParts := strings.Split(strings.TrimSpace(line), " ")
-		if len(lineParts) == 2 && (strings.Contains(lineParts[1], "zsh") ||
-			strings.Contains(lineParts[1], "bash") ||
-			strings.Contains(lineParts[1], "fish")) {
+		if len(lineParts) == 2 && slices.ContainsFunc(supportedShell, func(listElem string) bool {
+			return strings.HasPrefix(lineParts[1], listElem)
+		}) {
 			parsedProcessID, err := strconv.Atoi(lineParts[0])
 			if err == nil {
 				processOutputs = append(processOutputs, ProcessOutput{

pkg/os/shell/shell_windows_test.go

@@ -1,51 +1,137 @@
 package shell
 
 import (
-	"math"
-	"os"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
 )
 
-func TestDetect(t *testing.T) {
-	defer func(shell string) { os.Setenv("SHELL", shell) }(os.Getenv("SHELL"))
-	os.Setenv("SHELL", "")
-
-	shell, err := detect()
+func TestDetect_WhenUnknownShell_ThenDefaultToCmdShell(t *testing.T) {
+	tests := []struct {
+		name              string
+		processTree       []MockedProcess
+		expectedShellType string
+	}{
+		{
+			"failure to get process details for given pid",
+			[]MockedProcess{},
+			"",
+		},
+		{
+			"failure while getting name of process",
+			[]MockedProcess{
+				{
+					name: "crc.exe",
+				},
+				{
+					nameGetFails: true,
+				},
+			},
+			"",
+		},
+		{
+			"failure while getting ppid of process",
+			[]MockedProcess{
+				{
+					name: "crc.exe",
+				},
+				{
+					parentGetFails: true,
+				},
+			},
+			"",
+		},
+		{
+			"failure when no shell process in process tree",
+			[]MockedProcess{
+				{
+					name: "crc.exe",
+				},
+				{
+					name: "unknown.exe",
+				},
+			},
+			"",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			// Given
+			currentProcessSupplier = func() AbstractProcess {
+				return createNewMockProcessTreeFrom(tt.processTree)
+			}
 
-	assert.Contains(t, supportedShell, shell)
-	assert.NoError(t, err)
-}
+			// When
+			shell, err := detect()
 
-func TestGetNameAndItsPpidOfCurrent(t *testing.T) {
-	pid := os.Getpid()
-	if pid < 0 || pid > math.MaxUint32 {
-		assert.Fail(t, "integer overflow detected")
-	}
-	shell, shellppid, err := getNameAndItsPpid(uint32(pid))
-	assert.Equal(t, "shell.test.exe", shell)
-	ppid := os.Getppid()
-	if ppid < 0 || ppid > math.MaxUint32 {
-		assert.Fail(t, "integer overflow detected")
+			// Then
+			assert.NoError(t, err)
+			assert.Equal(t, "cmd", shell)
+		})
 	}
-	assert.Equal(t, uint32(ppid), shellppid)
-	assert.NoError(t, err)
 }
 
-func TestGetNameAndItsPpidOfParent(t *testing.T) {
-	pid := os.Getppid()
-	if pid < 0 || pid > math.MaxUint32 {
-		assert.Fail(t, "integer overflow detected")
+func TestDetect_GivenProcessTree_ThenReturnShellProcessWithCorrespondingParentPID(t *testing.T) {
+	tests := []struct {
+		name              string
+		processTree       []MockedProcess
+		expectedShellType string
+	}{
+		{
+			"bash shell, then detect bash shell",
+			[]MockedProcess{
+				{
+					name: "crc.exe",
+				},
+				{
+					name: "bash.exe",
+				},
+			},
+			"bash",
+		},
+		{
+			"powershell, then detect powershell",
+			[]MockedProcess{
+				{
+					name: "crc.exe",
+				},
+				{
+					name: "powershell.exe",
+				},
+			},
+			"powershell",
+		},
+		{
+			"cmd shell, then detect fish shell",
+			[]MockedProcess{
+				{
+					name: "crc.exe",
+				},
+				{
+					name: "cmd.exe",
+				},
+			},
+			"cmd",
+		},
 	}
-	shell, _, err := getNameAndItsPpid(uint32(pid))
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			// Given
+			currentProcessSupplier = func() AbstractProcess {
+				return createNewMockProcessTreeFrom(tt.processTree)
+			}
+			// When
+			shell, err := detect()
 
-	assert.Equal(t, "go.exe", shell)
-	assert.NoError(t, err)
+			// Then
+			assert.Equal(t, tt.expectedShellType, shell)
+			assert.NoError(t, err)
+		})
+	}
 }
 
 func TestSupportedShells(t *testing.T) {
-	assert.Equal(t, []string{"cmd", "powershell", "bash", "zsh", "fish"}, supportedShell)
+	assert.Equal(t, []string{"cmd", "powershell", "wsl", "bash", "zsh", "fish"}, supportedShell)
 }
 
 func TestShellType(t *testing.T) {