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feat: discover shell login options from /etc/shells #97

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7 changes: 7 additions & 0 deletions cli/cli_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -3,6 +3,7 @@ package cli
import (
"fmt"
"github.com/arran4/gocdm/auth"
"github.com/arran4/gocdm/session"
"github.com/arran4/gocdm/x11"
"io"
"os"
Expand Down Expand Up @@ -102,6 +103,12 @@ func TestRunDryRunNoSessions(t *testing.T) {
})
t.Setenv("HOME", tmpHome)
t.Setenv("XDG_CONFIG_HOME", tmpHome)

origShellsFile := session.ShellsFile
session.ShellsFile = tmpHome + "/empty-shells-file-doesnt-exist"
t.Cleanup(func() {
session.ShellsFile = origShellsFile
})
exited := false
code := -1
mockExit := func(c int) {
Expand Down
37 changes: 37 additions & 0 deletions session/discovery.go
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Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,7 @@ var (
X11SessionsDir = "/etc/X11/Sessions"
XSessionsDir = "/usr/share/xsessions"
WaylandSessionsDir = "/usr/share/wayland-sessions"
ShellsFile = "/etc/shells"
)

type Session struct {
Expand Down Expand Up @@ -121,6 +122,14 @@ func (d *Discoverer) Discover(userHome string) ([]Session, error) {
}
}

// Try /etc/shells for console logins
shellSessions, err := d.discoverShellSessions()
if err == nil {
for _, s := range shellSessions {
addSession(s)
}
}

// Sort sessions by name
sort.SliceStable(sessions, func(i, j int) bool {
return sessions[i].Name < sessions[j].Name
Expand Down Expand Up @@ -214,6 +223,34 @@ func (d *Discoverer) discoverWaylandSessions() ([]Session, error) {
return d.discoverCustomSessions(WaylandSessionsDir, "W")
}

func (d *Discoverer) discoverShellSessions() ([]Session, error) {
file, err := os.Open(ShellsFile)
if err != nil {
return nil, err
}
defer file.Close()

var sessions []Session
scanner := bufio.NewScanner(file)
for scanner.Scan() {
line := strings.TrimSpace(scanner.Text())
if line == "" || strings.HasPrefix(line, "#") {
continue
}

if _, err := d.ExecLookPath(line); err == nil {
name := filepath.Base(line) + " shell"
sessions = append(sessions, Session{
Name: name,
Exec: line,
Type: "C",
Path: ShellsFile,
})
}
}
Comment on lines +235 to +250
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@gemini-code-assist gemini-code-assist Bot Apr 15, 2026

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medium

The bufio.Scanner loop finishes without checking for errors. It is a best practice to check scanner.Err() after the loop to ensure that the file was read completely and no I/O errors occurred during scanning.

	for scanner.Scan() {
		line := strings.TrimSpace(scanner.Text())
		if line == "" || strings.HasPrefix(line, "#") {
			continue
		}

		if _, err := d.ExecLookPath(line); err == nil {
			name := filepath.Base(line) + " shell"
			sessions = append(sessions, Session{
				Name: name,
				Exec: line,
				Type: "C",
				Path: ShellsFile,
			})
		}
	}

	if err := scanner.Err(); err != nil {
		return nil, err
	}

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@arran4 arran4 Apr 15, 2026

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medium

The bufio.Scanner loop finishes without checking for errors. It is a best practice to check scanner.Err() after the loop to ensure that the file was read completely and no I/O errors occurred during scanning.

	for scanner.Scan() {
		line := strings.TrimSpace(scanner.Text())
		if line == "" || strings.HasPrefix(line, "#") {
			continue
		}

		if _, err := d.ExecLookPath(line); err == nil {
			name := filepath.Base(line) + " shell"
			sessions = append(sessions, Session{
				Name: name,
				Exec: line,
				Type: "C",
				Path: ShellsFile,
			})
		}
	}

	if err := scanner.Err(); err != nil {
		return nil, err
	}

@jules

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@google-labs-jules google-labs-jules Bot Apr 15, 2026

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Good point. I've added the error check using scanner.Err() after the bufio.Scanner loop in discoverShellSessions to catch any I/O errors that might occur during the file reading.

return sessions, nil
}

// stripFreedesktopExecVariables removes Freedesktop Exec field codes from the command line.
// Some window managers or display managers specify %f, %u, etc., in their .desktop files.
// For a display manager, we generally want to remove these or ignore them.
Expand Down
19 changes: 17 additions & 2 deletions session/discovery_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -30,8 +30,9 @@ func TestDiscoverSessions(t *testing.T) {
waylandSessionsDir := filepath.Join(tmpDir, "usr", "share", "wayland-sessions")
userHome := filepath.Join(tmpDir, "home", "user")
userConfigWayland := filepath.Join(userHome, ".config", "wayland-sessions")
etcDir := filepath.Join(tmpDir, "etc")

dirs := []string{x11Dir, xsessionsDir, waylandSessionsDir, userHome, userConfigWayland}
dirs := []string{x11Dir, xsessionsDir, waylandSessionsDir, userHome, userConfigWayland, etcDir}
for _, d := range dirs {
if err := os.MkdirAll(d, 0755); err != nil {
t.Fatal(err)
Expand Down Expand Up @@ -72,19 +73,31 @@ func TestDiscoverSessions(t *testing.T) {
t.Fatal(err)
}

// 6. Shells file
shellsContent := "# /etc/shells\n" +
"/not/a/real/path/to/shell\n" + // will not be found by exec.LookPath
testCommand + "\n"
shellsPath := filepath.Join(etcDir, "shells")
if err := os.WriteFile(shellsPath, []byte(shellsContent), 0644); err != nil {
t.Fatal(err)
}

// Save original vars
origX11 := X11SessionsDir
origXSessions := XSessionsDir
origWaylandSessions := WaylandSessionsDir
origShellsFile := ShellsFile
defer func() {
X11SessionsDir = origX11
XSessionsDir = origXSessions
WaylandSessionsDir = origWaylandSessions
ShellsFile = origShellsFile
}()

X11SessionsDir = x11Dir
XSessionsDir = xsessionsDir
WaylandSessionsDir = waylandSessionsDir
ShellsFile = shellsPath

// Test Discovery
sessions, err := DiscoverSessions(userHome)
Expand All @@ -98,8 +111,9 @@ func TestDiscoverSessions(t *testing.T) {
// 3. legacy_x11 (Type X)
// 4. Standard X Session (Type X)
// 5. Wayland Session (Type W)
// 6. Shell Session (Type C)

expectedCount := 5
expectedCount := 6
if len(sessions) != expectedCount {
t.Errorf("Expected %d sessions, got %d", expectedCount, len(sessions))
for _, s := range sessions {
Expand All @@ -119,6 +133,7 @@ func TestDiscoverSessions(t *testing.T) {
"legacy_x11": "X",
"Standard X Session": "X",
"Wayland Session": "W",
filepath.Base(testCommand) + " shell": "C",
}

for name, typ := range expectations {
Expand Down
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