refactor: increase group name limit to 255 (#15377)

Close https://github.com/coder/coder/issues/15184

codersdk/name.go

@@ -1,6 +1,7 @@
 package codersdk
 
 import (
+	"fmt"
 	"regexp"
 	"strings"
 
@@ -98,9 +99,12 @@ func UserRealNameValid(str string) error {
 
 // GroupNameValid returns whether the input string is a valid group name.
 func GroupNameValid(str string) error {
-	// 36 is to support using UUIDs as the group name.
-	if len(str) > 36 {
-		return xerrors.New("must be <= 36 characters")
+	// We want to support longer names for groups to allow users to sync their
+	// group names with their identity providers without manual mapping. Related
+	// to: https://github.com/coder/coder/issues/15184
+	limit := 255
+	if len(str) > limit {
+		return xerrors.New(fmt.Sprintf("must be <= %d characters", limit))
 	}
 	// Avoid conflicts with routes like /groups/new and /groups/create.
 	if str == "new" || str == "create" {

codersdk/name_test.go

@@ -8,6 +8,7 @@ import (
 	"github.com/stretchr/testify/require"
 
 	"github.com/coder/coder/v2/codersdk"
+	"github.com/coder/coder/v2/cryptorand"
 	"github.com/coder/coder/v2/testutil"
 )
 
@@ -254,3 +255,41 @@ func TestUserRealNameValid(t *testing.T) {
 		})
 	}
 }
+
+func TestGroupNameValid(t *testing.T) {
+	t.Parallel()
+
+	random255String, err := cryptorand.String(255)
+	require.NoError(t, err, "failed to generate 255 random string")
+	random256String, err := cryptorand.String(256)
+	require.NoError(t, err, "failed to generate 256 random string")
+
+	testCases := []struct {
+		Name  string
+		Valid bool
+	}{
+		{"", false},
+		{"my-group", true},
+		{"create", false},
+		{"new", false},
+		{"Lord Voldemort Team", false},
+		{random255String, true},
+		{random256String, false},
+	}
+	for _, testCase := range testCases {
+		testCase := testCase
+		t.Run(testCase.Name, func(t *testing.T) {
+			t.Parallel()
+			err := codersdk.GroupNameValid(testCase.Name)
+			assert.Equal(
+				t,
+				testCase.Valid,
+				err == nil,
+				"Test case %s failed: expected valid=%t but got error: %v",
+				testCase.Name,
+				testCase.Valid,
+				err,
+			)
+		})
+	}
+}