validate schedule-derived backup names don't exceed length limit

Signed-off-by: samay43 <samayrbhat43@gmail.com>

pkg/cmd/cli/backup/create.go

@@ -216,6 +216,17 @@ func (o *CreateOptions) Validate(c *cobra.Command, args []string, f client.Facto
 			return fmt.Errorf("invalid backup name %q: %s", o.Name, strings.Join(errs, "; "))
 		}
 	}
+	// When a backup name will be generated from the schedule (i.e. FromSchedule
+	// is set and no explicit name was given), ensure the schedule name leaves
+	// enough room for the generated timestamp suffix ("-" + 14-digit timestamp,
+	// 15 characters total) within the DNS1123 subdomain length limit.
+	if o.FromSchedule != "" && o.Name == "" {
+		const timestampSuffixLen = 15 // "-" + "20060102150405"
+		maxScheduleNameLen := validation.DNS1123SubdomainMaxLength - timestampSuffixLen
+		if len(o.FromSchedule) > maxScheduleNameLen {
+			return fmt.Errorf("schedule name %q is too long: must be %d characters or fewer to leave room for the generated timestamp suffix", o.FromSchedule, maxScheduleNameLen)
+		}
+	}
 	errs := collections.ValidateNamespaceIncludesExcludes(o.IncludeNamespaces, o.ExcludeNamespaces)
 	if len(errs) > 0 {
 		return kubeerrs.NewAggregate(errs)

pkg/cmd/cli/backup/create_test.go

@@ -538,6 +538,20 @@ func TestCreateOptions_Validate(t *testing.T) {
 			args:         []string{},
 			expectError:  false,
 		},
+		{
+			name:         "should pass when schedule name leaves room for timestamp suffix",
+			optName:      "",
+			fromSchedule: strings.Repeat("a", 238), // exactly at the 238-char limit
+			args:         []string{},
+			expectError:  false,
+		},
+		{
+			name:         "should error when schedule name is too long to leave room for timestamp suffix",
+			optName:      "",
+			fromSchedule: strings.Repeat("a", 239), // one over the 238-char limit
+			args:         []string{},
+			expectError:  true,
+		},
 	}
 
 	for _, tc := range testCases {