fix: improve SSA option error message and use constant over magic string

- Change error to "invalid server-side apply option" (was misleadingly
  referencing "release server-side apply method")
- Use string(release.ApplyMethodServerSideApply) constant instead of "ssa"
- Update test assertions to match new error format

Signed-off-by: ayushi-work <ayushi.work007@gmail.com>

pkg/action/action.go

@@ -735,13 +735,13 @@ func determineReleaseSSApplyMethod(serverSideApply bool) release.ApplyMethod {
 func getServerSideApplyValue(serverSideOption string, releaseApplyMethod string) (bool, error) {
 	switch serverSideOption {
 	case "auto":
-		return releaseApplyMethod == "ssa", nil
+		return releaseApplyMethod == string(release.ApplyMethodServerSideApply), nil
 	case "false":
 		return false, nil
 	case "true":
 		return true, nil
 	default:
-		return false, fmt.Errorf("invalid/unknown release server-side apply method: %s", serverSideOption)
+		return false, fmt.Errorf("invalid server-side apply option %q (must be one of: auto, true, false)", serverSideOption)
 	}
 }
 

pkg/action/uninstall_test.go

@@ -409,7 +409,7 @@ func TestGetServerSideApplyValue_WithUninstallScenarios(t *testing.T) {
 			name:            "invalid option",
 			serverSideOption: "invalid",
 			expectError:     true,
-			errorContains:   "invalid/unknown release server-side apply method",
+			errorContains:   "invalid server-side apply option",
 		},
 	}
 
@@ -459,5 +459,5 @@ func TestUninstall_ServerSideApply_InvalidOption_WithHooks(t *testing.T) {
 
 	_, err := unAction.Run(rel.Name)
 	assert.Error(t, err)
-	assert.Contains(t, err.Error(), "invalid/unknown release server-side apply method")
+	assert.Contains(t, err.Error(), "invalid server-side apply option")
 }

pkg/action/upgrade_test.go

@@ -730,7 +730,7 @@ func TestGetServerSideApplyValue(t *testing.T) {
 			name:                   "action invalid option",
 			actionServerSideOption: "invalid",
 			releaseApplyMethod:     "ssa",
-			expectedErrorMsg:       "invalid/unknown release server-side apply method: invalid",
+			expectedErrorMsg:       "invalid server-side apply option \"invalid\" (must be one of: auto, true, false)",
 		},
 	}