[bugfix] Allow unsetting filter expiration dates (#3560)

* Regression tests for #3497 (v1 and v2)
* use Nullable type for v2 form.expires_in

---------

Co-authored-by: tobi <tobi.smethurst@protonmail.com>

internal/api/client/filters/v1/filterpost_test.go

@@ -41,6 +41,7 @@ func (suite *FiltersTestSuite) postFilter(
 	irreversible *bool,
 	wholeWord *bool,
 	expiresIn *int,
+	expiresInStr *string,
 	requestJson *string,
 	expectedHTTPStatus int,
 	expectedBody string,
@@ -75,6 +76,8 @@ func (suite *FiltersTestSuite) postFilter(
 		}
 		if expiresIn != nil {
 			ctx.Request.Form["expires_in"] = []string{strconv.Itoa(*expiresIn)}
+		} else if expiresInStr != nil {
+			ctx.Request.Form["expires_in"] = []string{*expiresInStr}
 		}
 	}
 
@@ -124,7 +127,7 @@ func (suite *FiltersTestSuite) TestPostFilterFull() {
 	irreversible := false
 	wholeWord := true
 	expiresIn := 86400
-	filter, err := suite.postFilter(&phrase, &context, &irreversible, &wholeWord, &expiresIn, nil, http.StatusOK, "")
+	filter, err := suite.postFilter(&phrase, &context, &irreversible, &wholeWord, &expiresIn, nil, nil, http.StatusOK, "")
 	if err != nil {
 		suite.FailNow(err.Error())
 	}
@@ -155,7 +158,7 @@ func (suite *FiltersTestSuite) TestPostFilterFullJSON() {
 		"whole_word": true,
 		"expires_in": 86400.1
 	}`
-	filter, err := suite.postFilter(nil, nil, nil, nil, nil, &requestJson, http.StatusOK, "")
+	filter, err := suite.postFilter(nil, nil, nil, nil, nil, nil, &requestJson, http.StatusOK, "")
 	if err != nil {
 		suite.FailNow(err.Error())
 	}
@@ -182,7 +185,7 @@ func (suite *FiltersTestSuite) TestPostFilterMinimal() {
 
 	phrase := "GNU/Linux"
 	context := []string{"home"}
-	filter, err := suite.postFilter(&phrase, &context, nil, nil, nil, nil, http.StatusOK, "")
+	filter, err := suite.postFilter(&phrase, &context, nil, nil, nil, nil, nil, http.StatusOK, "")
 	if err != nil {
 		suite.FailNow(err.Error())
 	}
@@ -203,7 +206,7 @@ func (suite *FiltersTestSuite) TestPostFilterMinimal() {
 func (suite *FiltersTestSuite) TestPostFilterEmptyPhrase() {
 	phrase := ""
 	context := []string{"home"}
-	_, err := suite.postFilter(&phrase, &context, nil, nil, nil, nil, http.StatusUnprocessableEntity, "")
+	_, err := suite.postFilter(&phrase, &context, nil, nil, nil, nil, nil, http.StatusUnprocessableEntity, "")
 	if err != nil {
 		suite.FailNow(err.Error())
 	}
@@ -211,7 +214,7 @@ func (suite *FiltersTestSuite) TestPostFilterEmptyPhrase() {
 
 func (suite *FiltersTestSuite) TestPostFilterMissingPhrase() {
 	context := []string{"home"}
-	_, err := suite.postFilter(nil, &context, nil, nil, nil, nil, http.StatusUnprocessableEntity, "")
+	_, err := suite.postFilter(nil, &context, nil, nil, nil, nil, nil, http.StatusUnprocessableEntity, "")
 	if err != nil {
 		suite.FailNow(err.Error())
 	}
@@ -220,7 +223,7 @@ func (suite *FiltersTestSuite) TestPostFilterMissingPhrase() {
 func (suite *FiltersTestSuite) TestPostFilterEmptyContext() {
 	phrase := "GNU/Linux"
 	context := []string{}
-	_, err := suite.postFilter(&phrase, &context, nil, nil, nil, nil, http.StatusUnprocessableEntity, "")
+	_, err := suite.postFilter(&phrase, &context, nil, nil, nil, nil, nil, http.StatusUnprocessableEntity, "")
 	if err != nil {
 		suite.FailNow(err.Error())
 	}
@@ -228,7 +231,7 @@ func (suite *FiltersTestSuite) TestPostFilterEmptyContext() {
 
 func (suite *FiltersTestSuite) TestPostFilterMissingContext() {
 	phrase := "GNU/Linux"
-	_, err := suite.postFilter(&phrase, nil, nil, nil, nil, nil, http.StatusUnprocessableEntity, "")
+	_, err := suite.postFilter(&phrase, nil, nil, nil, nil, nil, nil, http.StatusUnprocessableEntity, "")
 	if err != nil {
 		suite.FailNow(err.Error())
 	}
@@ -237,8 +240,37 @@ func (suite *FiltersTestSuite) TestPostFilterMissingContext() {
 // There should be a filter with this phrase as its title in our test fixtures. Creating another should fail.
 func (suite *FiltersTestSuite) TestPostFilterTitleConflict() {
 	phrase := "fnord"
-	_, err := suite.postFilter(&phrase, nil, nil, nil, nil, nil, http.StatusUnprocessableEntity, "")
+	_, err := suite.postFilter(&phrase, nil, nil, nil, nil, nil, nil, http.StatusUnprocessableEntity, "")
 	if err != nil {
 		suite.FailNow(err.Error())
 	}
 }
+
+// postFilterWithExpiration creates a filter with optional expiration.
+func (suite *FiltersTestSuite) postFilterWithExpiration(phrase *string, expiresIn *int, expiresInStr *string, requestJson *string) *apimodel.FilterV1 {
+	context := []string{"home"}
+	filter, err := suite.postFilter(phrase, &context, nil, nil, expiresIn, expiresInStr, requestJson, http.StatusOK, "")
+	if err != nil {
+		suite.FailNow(err.Error())
+	}
+	return filter
+}
+
+// Regression test for https://github.com/superseriousbusiness/gotosocial/issues/3497
+func (suite *FiltersTestSuite) TestPostFilterWithEmptyStringExpiration() {
+	title := "Form Sins"
+	expiresInStr := ""
+	filter := suite.postFilterWithExpiration(&title, nil, &expiresInStr, nil)
+	suite.Nil(filter.ExpiresAt)
+}
+
+// Regression test related to https://github.com/superseriousbusiness/gotosocial/issues/3497
+func (suite *FiltersTestSuite) TestPostFilterWithNullExpirationJSON() {
+	requestJson := `{
+		"phrase": "JSON Sins",
+		"context": ["home"],
+		"expires_in": null
+	}`
+	filter := suite.postFilterWithExpiration(nil, nil, nil, &requestJson)
+	suite.Nil(filter.ExpiresAt)
+}

internal/api/client/filters/v1/filterput_test.go

@@ -42,6 +42,7 @@ func (suite *FiltersTestSuite) putFilter(
 	irreversible *bool,
 	wholeWord *bool,
 	expiresIn *int,
+	expiresInStr *string,
 	requestJson *string,
 	expectedHTTPStatus int,
 	expectedBody string,
@@ -76,6 +77,8 @@ func (suite *FiltersTestSuite) putFilter(
 		}
 		if expiresIn != nil {
 			ctx.Request.Form["expires_in"] = []string{strconv.Itoa(*expiresIn)}
+		} else if expiresInStr != nil {
+			ctx.Request.Form["expires_in"] = []string{*expiresInStr}
 		}
 	}
 
@@ -128,7 +131,7 @@ func (suite *FiltersTestSuite) TestPutFilterFull() {
 	irreversible := false
 	wholeWord := true
 	expiresIn := 86400
-	filter, err := suite.putFilter(id, &phrase, &context, &irreversible, &wholeWord, &expiresIn, nil, http.StatusOK, "")
+	filter, err := suite.putFilter(id, &phrase, &context, &irreversible, &wholeWord, &expiresIn, nil, nil, http.StatusOK, "")
 	if err != nil {
 		suite.FailNow(err.Error())
 	}
@@ -160,7 +163,7 @@ func (suite *FiltersTestSuite) TestPutFilterFullJSON() {
 		"whole_word": true,
 		"expires_in": 86400.1
 	}`
-	filter, err := suite.putFilter(id, nil, nil, nil, nil, nil, &requestJson, http.StatusOK, "")
+	filter, err := suite.putFilter(id, nil, nil, nil, nil, nil, nil, &requestJson, http.StatusOK, "")
 	if err != nil {
 		suite.FailNow(err.Error())
 	}
@@ -188,7 +191,7 @@ func (suite *FiltersTestSuite) TestPutFilterMinimal() {
 	id := suite.testFilterKeywords["local_account_1_filter_1_keyword_1"].ID
 	phrase := "GNU/Linux"
 	context := []string{"home"}
-	filter, err := suite.putFilter(id, &phrase, &context, nil, nil, nil, nil, http.StatusOK, "")
+	filter, err := suite.putFilter(id, &phrase, &context, nil, nil, nil, nil, nil, http.StatusOK, "")
 	if err != nil {
 		suite.FailNow(err.Error())
 	}
@@ -210,7 +213,7 @@ func (suite *FiltersTestSuite) TestPutFilterEmptyPhrase() {
 	id := suite.testFilterKeywords["local_account_1_filter_1_keyword_1"].ID
 	phrase := ""
 	context := []string{"home"}
-	_, err := suite.putFilter(id, &phrase, &context, nil, nil, nil, nil, http.StatusUnprocessableEntity, "")
+	_, err := suite.putFilter(id, &phrase, &context, nil, nil, nil, nil, nil, http.StatusUnprocessableEntity, "")
 	if err != nil {
 		suite.FailNow(err.Error())
 	}
@@ -219,7 +222,7 @@ func (suite *FiltersTestSuite) TestPutFilterEmptyPhrase() {
 func (suite *FiltersTestSuite) TestPutFilterMissingPhrase() {
 	id := suite.testFilterKeywords["local_account_1_filter_1_keyword_1"].ID
 	context := []string{"home"}
-	_, err := suite.putFilter(id, nil, &context, nil, nil, nil, nil, http.StatusUnprocessableEntity, "")
+	_, err := suite.putFilter(id, nil, &context, nil, nil, nil, nil, nil, http.StatusUnprocessableEntity, "")
 	if err != nil {
 		suite.FailNow(err.Error())
 	}
@@ -229,7 +232,7 @@ func (suite *FiltersTestSuite) TestPutFilterEmptyContext() {
 	id := suite.testFilterKeywords["local_account_1_filter_1_keyword_1"].ID
 	phrase := "GNU/Linux"
 	context := []string{}
-	_, err := suite.putFilter(id, &phrase, &context, nil, nil, nil, nil, http.StatusUnprocessableEntity, "")
+	_, err := suite.putFilter(id, &phrase, &context, nil, nil, nil, nil, nil, http.StatusUnprocessableEntity, "")
 	if err != nil {
 		suite.FailNow(err.Error())
 	}
@@ -238,7 +241,7 @@ func (suite *FiltersTestSuite) TestPutFilterEmptyContext() {
 func (suite *FiltersTestSuite) TestPutFilterMissingContext() {
 	id := suite.testFilterKeywords["local_account_1_filter_1_keyword_1"].ID
 	phrase := "GNU/Linux"
-	_, err := suite.putFilter(id, &phrase, nil, nil, nil, nil, nil, http.StatusUnprocessableEntity, "")
+	_, err := suite.putFilter(id, &phrase, nil, nil, nil, nil, nil, nil, http.StatusUnprocessableEntity, "")
 	if err != nil {
 		suite.FailNow(err.Error())
 	}
@@ -248,7 +251,7 @@ func (suite *FiltersTestSuite) TestPutFilterMissingContext() {
 func (suite *FiltersTestSuite) TestPutFilterTitleConflict() {
 	id := suite.testFilterKeywords["local_account_1_filter_1_keyword_1"].ID
 	phrase := "metasyntactic variables"
-	_, err := suite.putFilter(id, &phrase, nil, nil, nil, nil, nil, http.StatusUnprocessableEntity, "")
+	_, err := suite.putFilter(id, &phrase, nil, nil, nil, nil, nil, nil, http.StatusUnprocessableEntity, "")
 	if err != nil {
 		suite.FailNow(err.Error())
 	}
@@ -258,7 +261,7 @@ func (suite *FiltersTestSuite) TestPutAnotherAccountsFilter() {
 	id := suite.testFilterKeywords["local_account_2_filter_1_keyword_1"].ID
 	phrase := "GNU/Linux"
 	context := []string{"home"}
-	_, err := suite.putFilter(id, &phrase, &context, nil, nil, nil, nil, http.StatusNotFound, `{"error":"Not Found"}`)
+	_, err := suite.putFilter(id, &phrase, &context, nil, nil, nil, nil, nil, http.StatusNotFound, `{"error":"Not Found"}`)
 	if err != nil {
 		suite.FailNow(err.Error())
 	}
@@ -268,8 +271,60 @@ func (suite *FiltersTestSuite) TestPutNonexistentFilter() {
 	id := "not_even_a_real_ULID"
 	phrase := "GNU/Linux"
 	context := []string{"home"}
-	_, err := suite.putFilter(id, &phrase, &context, nil, nil, nil, nil, http.StatusNotFound, `{"error":"Not Found"}`)
+	_, err := suite.putFilter(id, &phrase, &context, nil, nil, nil, nil, nil, http.StatusNotFound, `{"error":"Not Found"}`)
 	if err != nil {
 		suite.FailNow(err.Error())
 	}
 }
+
+// setFilterExpiration sets filter expiration.
+func (suite *FiltersTestSuite) setFilterExpiration(id string, phrase *string, expiresIn *int, expiresInStr *string, requestJson *string) *apimodel.FilterV1 {
+	context := []string{"home"}
+	filter, err := suite.putFilter(id, phrase, &context, nil, nil, expiresIn, expiresInStr, requestJson, http.StatusOK, "")
+	if err != nil {
+		suite.FailNow(err.Error())
+	}
+	return filter
+}
+
+// Regression test for https://github.com/superseriousbusiness/gotosocial/issues/3497
+func (suite *FiltersTestSuite) TestPutFilterUnsetExpirationDateEmptyString() {
+	filterKeyword := suite.testFilterKeywords["local_account_1_filter_1_keyword_1"]
+	id := filterKeyword.ID
+	phrase := filterKeyword.Keyword
+
+	// Setup: set an expiration date for the filter.
+	expiresIn := 86400
+	filter := suite.setFilterExpiration(id, &phrase, &expiresIn, nil, nil)
+	if !suite.NotNil(filter.ExpiresAt) {
+		suite.FailNow("Test precondition failed")
+	}
+
+	// Unset the filter's expiration date by setting it to an empty string.
+	expiresInStr := ""
+	filter = suite.setFilterExpiration(id, &phrase, nil, &expiresInStr, nil)
+	suite.Nil(filter.ExpiresAt)
+}
+
+// Regression test related to https://github.com/superseriousbusiness/gotosocial/issues/3497
+func (suite *FiltersTestSuite) TestPutFilterUnsetExpirationDateNullJSON() {
+	filterKeyword := suite.testFilterKeywords["local_account_1_filter_1_keyword_1"]
+	id := filterKeyword.ID
+	phrase := filterKeyword.Keyword
+
+	// Setup: set an expiration date for the filter.
+	expiresIn := 86400
+	filter := suite.setFilterExpiration(id, &phrase, &expiresIn, nil, nil)
+	if !suite.NotNil(filter.ExpiresAt) {
+		suite.FailNow("Test precondition failed")
+	}
+
+	// Unset the filter's expiration date by setting it to a null literal.
+	requestJson := `{
+		"phrase": "fnord",
+		"context": ["home"],
+		"expires_in": null
+	}`
+	filter = suite.setFilterExpiration(id, nil, nil, nil, &requestJson)
+	suite.Nil(filter.ExpiresAt)
+}

internal/api/client/filters/v1/validate.go

@@ -46,12 +46,11 @@ func validateNormalizeCreateUpdateFilter(form *apimodel.FilterCreateUpdateReques
 		return errors.New("irreversible aka server-side drop filters are not supported yet")
 	}
 
-	// Normalize filter expiry if necessary.
+	// If `expires_in` was provided
-	if form.ExpiresInI != nil {
+	// as JSON, then normalize it.
-		// If we parsed this as JSON, expires_in
+	if form.ExpiresInI.IsSpecified() {
-		// may be either a float64 or a string.
 		var err error
-		form.ExpiresIn, err = apiutil.ParseDuration(
+		form.ExpiresIn, err = apiutil.ParseNullableDuration(
 			form.ExpiresInI,
 			"expires_in",
 		)
@@ -60,10 +59,5 @@ func validateNormalizeCreateUpdateFilter(form *apimodel.FilterCreateUpdateReques
 		}
 	}
 
-	// Interpret zero as indefinite duration.
-	if form.ExpiresIn != nil && *form.ExpiresIn == 0 {
-		form.ExpiresIn = nil
-	}
-
 	return nil
 }

internal/api/client/filters/v2/filterpost.go

@@ -225,12 +225,11 @@ func validateNormalizeCreateFilter(form *apimodel.FilterCreateRequestV2) error {
 	// Apply defaults for missing fields.
 	form.FilterAction = util.Ptr(action)
 
-	// Normalize filter expiry if necessary.
+	// If `expires_in` was provided
-	if form.ExpiresInI != nil {
+	// as JSON, then normalize it.
-		// If we parsed this as JSON, expires_in
+	if form.ExpiresInI.IsSpecified() {
-		// may be either a float64 or a string.
 		var err error
-		form.ExpiresIn, err = apiutil.ParseDuration(
+		form.ExpiresIn, err = apiutil.ParseNullableDuration(
 			form.ExpiresInI,
 			"expires_in",
 		)
@@ -239,11 +238,6 @@ func validateNormalizeCreateFilter(form *apimodel.FilterCreateRequestV2) error {
 		}
 	}
 
-	// Interpret zero as indefinite duration.
-	if form.ExpiresIn != nil && *form.ExpiresIn == 0 {
-		form.ExpiresIn = nil
-	}
-
 	// Normalize and validate new keywords and statuses.
 	for i, formKeyword := range form.Keywords {
 		if err := validate.FilterKeyword(formKeyword.Keyword); err != nil {

internal/api/client/filters/v2/filterpost_test.go

@@ -36,7 +36,7 @@
 	"github.com/superseriousbusiness/gotosocial/testrig"
 )
 
-func (suite *FiltersTestSuite) postFilter(title *string, context *[]string, action *string, expiresIn *int, keywordsAttributesKeyword *[]string, keywordsAttributesWholeWord *[]bool, statusesAttributesStatusID *[]string, requestJson *string, expectedHTTPStatus int, expectedBody string) (*apimodel.FilterV2, error) {
+func (suite *FiltersTestSuite) postFilter(title *string, context *[]string, action *string, expiresIn *int, expiresInStr *string, keywordsAttributesWholeWord *[]bool, statusesAttributesStatusID *[]string, requestJson *string, expectedHTTPStatus int, expectedBody string, keywordsAttributesKeyword *[]string) (*apimodel.FilterV2, error) {
 	// instantiate recorder + test context
 	recorder := httptest.NewRecorder()
 	ctx, _ := testrig.CreateGinTestContext(recorder, nil)
@@ -64,6 +64,8 @@ func (suite *FiltersTestSuite) postFilter(title *string, context *[]string, acti
 		}
 		if expiresIn != nil {
 			ctx.Request.Form["expires_in"] = []string{strconv.Itoa(*expiresIn)}
+		} else if expiresInStr != nil {
+			ctx.Request.Form["expires_in"] = []string{*expiresInStr}
 		}
 		if keywordsAttributesKeyword != nil {
 			ctx.Request.Form["keywords_attributes[][keyword]"] = *keywordsAttributesKeyword
@@ -130,7 +132,7 @@ func (suite *FiltersTestSuite) TestPostFilterFull() {
 	keywordsAttributesWholeWord := []bool{true, false}
 	// Checked in lexical order by status ID, so keep this sorted.
 	statusAttributesStatusID := []string{"01HEN2QRFA8H3C6QPN7RD4KSR6", "01HEWV37MHV8BAC8ANFGVRRM5D"}
-	filter, err := suite.postFilter(&title, &context, &action, &expiresIn, &keywordsAttributesKeyword, &keywordsAttributesWholeWord, &statusAttributesStatusID, nil, http.StatusOK, "")
+	filter, err := suite.postFilter(&title, &context, &action, &expiresIn, nil, &keywordsAttributesWholeWord, &statusAttributesStatusID, nil, http.StatusOK, "", &keywordsAttributesKeyword)
 	if err != nil {
 		suite.FailNow(err.Error())
 	}
@@ -197,7 +199,7 @@ func (suite *FiltersTestSuite) TestPostFilterFullJSON() {
 			}
 		]
 	}`
-	filter, err := suite.postFilter(nil, nil, nil, nil, nil, nil, nil, &requestJson, http.StatusOK, "")
+	filter, err := suite.postFilter(nil, nil, nil, nil, nil, nil, nil, &requestJson, http.StatusOK, "", nil)
 	if err != nil {
 		suite.FailNow(err.Error())
 	}
@@ -245,7 +247,7 @@ func (suite *FiltersTestSuite) TestPostFilterMinimal() {
 
 	title := "GNU/Linux"
 	context := []string{"home"}
-	filter, err := suite.postFilter(&title, &context, nil, nil, nil, nil, nil, nil, http.StatusOK, "")
+	filter, err := suite.postFilter(&title, &context, nil, nil, nil, nil, nil, nil, http.StatusOK, "", nil)
 	if err != nil {
 		suite.FailNow(err.Error())
 	}
@@ -267,7 +269,7 @@ func (suite *FiltersTestSuite) TestPostFilterMinimal() {
 func (suite *FiltersTestSuite) TestPostFilterEmptyTitle() {
 	title := ""
 	context := []string{"home"}
-	_, err := suite.postFilter(&title, &context, nil, nil, nil, nil, nil, nil, http.StatusUnprocessableEntity, "")
+	_, err := suite.postFilter(&title, &context, nil, nil, nil, nil, nil, nil, http.StatusUnprocessableEntity, "", nil)
 	if err != nil {
 		suite.FailNow(err.Error())
 	}
@@ -275,7 +277,7 @@ func (suite *FiltersTestSuite) TestPostFilterEmptyTitle() {
 
 func (suite *FiltersTestSuite) TestPostFilterMissingTitle() {
 	context := []string{"home"}
-	_, err := suite.postFilter(nil, &context, nil, nil, nil, nil, nil, nil, http.StatusUnprocessableEntity, "")
+	_, err := suite.postFilter(nil, &context, nil, nil, nil, nil, nil, nil, http.StatusUnprocessableEntity, "", nil)
 	if err != nil {
 		suite.FailNow(err.Error())
 	}
@@ -284,7 +286,7 @@ func (suite *FiltersTestSuite) TestPostFilterMissingTitle() {
 func (suite *FiltersTestSuite) TestPostFilterEmptyContext() {
 	title := "GNU/Linux"
 	context := []string{}
-	_, err := suite.postFilter(&title, &context, nil, nil, nil, nil, nil, nil, http.StatusUnprocessableEntity, "")
+	_, err := suite.postFilter(&title, &context, nil, nil, nil, nil, nil, nil, http.StatusUnprocessableEntity, "", nil)
 	if err != nil {
 		suite.FailNow(err.Error())
 	}
@@ -292,7 +294,7 @@ func (suite *FiltersTestSuite) TestPostFilterEmptyContext() {
 
 func (suite *FiltersTestSuite) TestPostFilterMissingContext() {
 	title := "GNU/Linux"
-	_, err := suite.postFilter(&title, nil, nil, nil, nil, nil, nil, nil, http.StatusUnprocessableEntity, "")
+	_, err := suite.postFilter(&title, nil, nil, nil, nil, nil, nil, nil, http.StatusUnprocessableEntity, "", nil)
 	if err != nil {
 		suite.FailNow(err.Error())
 	}
@@ -301,8 +303,37 @@ func (suite *FiltersTestSuite) TestPostFilterMissingContext() {
 // Creating another filter with the same title should fail.
 func (suite *FiltersTestSuite) TestPostFilterTitleConflict() {
 	title := suite.testFilters["local_account_1_filter_1"].Title
-	_, err := suite.postFilter(&title, nil, nil, nil, nil, nil, nil, nil, http.StatusUnprocessableEntity, "")
+	_, err := suite.postFilter(&title, nil, nil, nil, nil, nil, nil, nil, http.StatusUnprocessableEntity, "", nil)
 	if err != nil {
 		suite.FailNow(err.Error())
 	}
 }
+
+// postFilterWithExpiration creates a filter with optional expiration.
+func (suite *FiltersTestSuite) postFilterWithExpiration(title *string, expiresIn *int, expiresInStr *string, requestJson *string) *apimodel.FilterV2 {
+	context := []string{"home"}
+	filter, err := suite.postFilter(title, &context, nil, expiresIn, expiresInStr, nil, nil, requestJson, http.StatusOK, "", nil)
+	if err != nil {
+		suite.FailNow(err.Error())
+	}
+	return filter
+}
+
+// Regression test for https://github.com/superseriousbusiness/gotosocial/issues/3497
+func (suite *FiltersTestSuite) TestPostFilterWithEmptyStringExpiration() {
+	title := "Form Crimes"
+	expiresInStr := ""
+	filter := suite.postFilterWithExpiration(&title, nil, &expiresInStr, nil)
+	suite.Nil(filter.ExpiresAt)
+}
+
+// Regression test related to https://github.com/superseriousbusiness/gotosocial/issues/3497
+func (suite *FiltersTestSuite) TestPostFilterWithNullExpirationJSON() {
+	requestJson := `{
+		"title": "JSON Crimes",
+		"context": ["home"],
+		"expires_in": null
+	}`
+	filter := suite.postFilterWithExpiration(nil, nil, nil, &requestJson)
+	suite.Nil(filter.ExpiresAt)
+}

internal/api/client/filters/v2/filterput.go

@@ -269,12 +269,11 @@ func validateNormalizeUpdateFilter(form *apimodel.FilterUpdateRequestV2) error {
 		}
 	}
 
-	// Normalize filter expiry if necessary.
+	// If `expires_in` was provided
-	if form.ExpiresInI != nil {
+	// as JSON, then normalize it.
-		// If we parsed this as JSON, expires_in
+	if form.ExpiresInI.IsSpecified() {
-		// may be either a float64 or a string.
 		var err error
-		form.ExpiresIn, err = apiutil.ParseDuration(
+		form.ExpiresIn, err = apiutil.ParseNullableDuration(
 			form.ExpiresInI,
 			"expires_in",
 		)
@@ -283,11 +282,6 @@ func validateNormalizeUpdateFilter(form *apimodel.FilterUpdateRequestV2) error {
 		}
 	}
 
-	// Interpret zero as indefinite duration.
-	if form.ExpiresIn != nil && *form.ExpiresIn == 0 {
-		form.ExpiresIn = nil
-	}
-
 	// Normalize and validate updates.
 	for i, formKeyword := range form.Keywords {
 		if formKeyword.Keyword != nil {

internal/api/client/filters/v2/filterput_test.go

@@ -36,7 +36,7 @@
 	"github.com/superseriousbusiness/gotosocial/testrig"
 )
 
-func (suite *FiltersTestSuite) putFilter(filterID string, title *string, context *[]string, action *string, expiresIn *int, keywordsAttributesID *[]string, keywordsAttributesKeyword *[]string, keywordsAttributesWholeWord *[]bool, keywordsAttributesDestroy *[]bool, statusesAttributesID *[]string, statusesAttributesStatusID *[]string, statusesAttributesDestroy *[]bool, requestJson *string, expectedHTTPStatus int, expectedBody string) (*apimodel.FilterV2, error) {
+func (suite *FiltersTestSuite) putFilter(filterID string, title *string, context *[]string, action *string, expiresIn *int, expiresInStr *string, keywordsAttributesKeyword *[]string, keywordsAttributesWholeWord *[]bool, keywordsAttributesDestroy *[]bool, statusesAttributesID *[]string, statusesAttributesStatusID *[]string, statusesAttributesDestroy *[]bool, requestJson *string, expectedHTTPStatus int, expectedBody string, keywordsAttributesID *[]string) (*apimodel.FilterV2, error) {
 	// instantiate recorder + test context
 	recorder := httptest.NewRecorder()
 	ctx, _ := testrig.CreateGinTestContext(recorder, nil)
@@ -64,6 +64,8 @@ func (suite *FiltersTestSuite) putFilter(filterID string, title *string, context
 		}
 		if expiresIn != nil {
 			ctx.Request.Form["expires_in"] = []string{strconv.Itoa(*expiresIn)}
+		} else if expiresInStr != nil {
+			ctx.Request.Form["expires_in"] = []string{*expiresInStr}
 		}
 		if keywordsAttributesID != nil {
 			ctx.Request.Form["keywords_attributes[][id]"] = *keywordsAttributesID
@@ -159,7 +161,7 @@ func (suite *FiltersTestSuite) TestPutFilterFull() {
 	keywordsAttributesWholeWord := []bool{true, false, true}
 	keywordsAttributesDestroy := []bool{false, true}
 	statusesAttributesStatusID := []string{suite.testStatuses["remote_account_1_status_2"].ID}
-	filter, err := suite.putFilter(id, &title, &context, &action, &expiresIn, &keywordsAttributesID, &keywordsAttributesKeyword, &keywordsAttributesWholeWord, &keywordsAttributesDestroy, nil, &statusesAttributesStatusID, nil, nil, http.StatusOK, "")
+	filter, err := suite.putFilter(id, &title, &context, &action, &expiresIn, nil, &keywordsAttributesKeyword, &keywordsAttributesWholeWord, &keywordsAttributesDestroy, nil, &statusesAttributesStatusID, nil, nil, http.StatusOK, "", &keywordsAttributesID)
 	if err != nil {
 		suite.FailNow(err.Error())
 	}
@@ -231,7 +233,7 @@ func (suite *FiltersTestSuite) TestPutFilterFullJSON() {
 			}
 		]
 	}`
-	filter, err := suite.putFilter(id, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, &requestJson, http.StatusOK, "")
+	filter, err := suite.putFilter(id, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, &requestJson, http.StatusOK, "", nil)
 	if err != nil {
 		suite.FailNow(err.Error())
 	}
@@ -281,7 +283,7 @@ func (suite *FiltersTestSuite) TestPutFilterMinimal() {
 	id := suite.testFilters["local_account_1_filter_1"].ID
 	title := "GNU/Linux"
 	context := []string{"home"}
-	filter, err := suite.putFilter(id, &title, &context, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, http.StatusOK, "")
+	filter, err := suite.putFilter(id, &title, &context, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, http.StatusOK, "", nil)
 	if err != nil {
 		suite.FailNow(err.Error())
 	}
@@ -302,7 +304,7 @@ func (suite *FiltersTestSuite) TestPutFilterEmptyTitle() {
 	id := suite.testFilters["local_account_1_filter_1"].ID
 	title := ""
 	context := []string{"home"}
-	_, err := suite.putFilter(id, &title, &context, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, http.StatusUnprocessableEntity, `{"error":"Unprocessable Entity: filter title must be provided, and must be no more than 200 chars"}`)
+	_, err := suite.putFilter(id, &title, &context, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, http.StatusUnprocessableEntity, `{"error":"Unprocessable Entity: filter title must be provided, and must be no more than 200 chars"}`, nil)
 	if err != nil {
 		suite.FailNow(err.Error())
 	}
@@ -312,7 +314,7 @@ func (suite *FiltersTestSuite) TestPutFilterEmptyContext() {
 	id := suite.testFilters["local_account_1_filter_1"].ID
 	title := "GNU/Linux"
 	context := []string{}
-	_, err := suite.putFilter(id, &title, &context, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, http.StatusUnprocessableEntity, `{"error":"Unprocessable Entity: at least one filter context is required"}`)
+	_, err := suite.putFilter(id, &title, &context, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, http.StatusUnprocessableEntity, `{"error":"Unprocessable Entity: at least one filter context is required"}`, nil)
 	if err != nil {
 		suite.FailNow(err.Error())
 	}
@@ -322,7 +324,7 @@ func (suite *FiltersTestSuite) TestPutFilterEmptyContext() {
 func (suite *FiltersTestSuite) TestPutFilterTitleConflict() {
 	id := suite.testFilters["local_account_1_filter_1"].ID
 	title := suite.testFilters["local_account_1_filter_2"].Title
-	_, err := suite.putFilter(id, &title, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, http.StatusConflict, `{"error":"Conflict: you already have a filter with this title"}`)
+	_, err := suite.putFilter(id, &title, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, http.StatusConflict, `{"error":"Conflict: you already have a filter with this title"}`, nil)
 	if err != nil {
 		suite.FailNow(err.Error())
 	}
@@ -332,7 +334,7 @@ func (suite *FiltersTestSuite) TestPutAnotherAccountsFilter() {
 	id := suite.testFilters["local_account_2_filter_1"].ID
 	title := "GNU/Linux"
 	context := []string{"home"}
-	_, err := suite.putFilter(id, &title, &context, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, http.StatusNotFound, `{"error":"Not Found"}`)
+	_, err := suite.putFilter(id, &title, &context, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, http.StatusNotFound, `{"error":"Not Found"}`, nil)
 	if err != nil {
 		suite.FailNow(err.Error())
 	}
@@ -342,8 +344,70 @@ func (suite *FiltersTestSuite) TestPutNonexistentFilter() {
 	id := "not_even_a_real_ULID"
 	phrase := "GNU/Linux"
 	context := []string{"home"}
-	_, err := suite.putFilter(id, &phrase, &context, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, http.StatusNotFound, `{"error":"Not Found"}`)
+	_, err := suite.putFilter(id, &phrase, &context, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, http.StatusNotFound, `{"error":"Not Found"}`, nil)
 	if err != nil {
 		suite.FailNow(err.Error())
 	}
 }
+
+// setFilterExpiration sets filter expiration.
+func (suite *FiltersTestSuite) setFilterExpiration(id string, expiresIn *int, expiresInStr *string, requestJson *string) *apimodel.FilterV2 {
+	filter, err := suite.putFilter(id, nil, nil, nil, expiresIn, expiresInStr, nil, nil, nil, nil, nil, nil, requestJson, http.StatusOK, "", nil)
+	if err != nil {
+		suite.FailNow(err.Error())
+	}
+	return filter
+}
+
+// Regression test for https://github.com/superseriousbusiness/gotosocial/issues/3497
+func (suite *FiltersTestSuite) TestPutFilterUnsetExpirationDateEmptyString() {
+	id := suite.testFilters["local_account_1_filter_2"].ID
+
+	// Setup: set an expiration date for the filter.
+	expiresIn := 86400
+	filter := suite.setFilterExpiration(id, &expiresIn, nil, nil)
+	if !suite.NotNil(filter.ExpiresAt) {
+		suite.FailNow("Test precondition failed")
+	}
+
+	// Unset the filter's expiration date by setting it to an empty string.
+	expiresInStr := ""
+	filter = suite.setFilterExpiration(id, nil, &expiresInStr, nil)
+	suite.Nil(filter.ExpiresAt)
+}
+
+// Regression test related to https://github.com/superseriousbusiness/gotosocial/issues/3497
+func (suite *FiltersTestSuite) TestPutFilterUnsetExpirationDateNullJSON() {
+	id := suite.testFilters["local_account_1_filter_3"].ID
+
+	// Setup: set an expiration date for the filter.
+	expiresIn := 86400
+	filter := suite.setFilterExpiration(id, &expiresIn, nil, nil)
+	if !suite.NotNil(filter.ExpiresAt) {
+		suite.FailNow("Test precondition failed")
+	}
+
+	// Unset the filter's expiration date by setting it to a null literal.
+	requestJson := `{
+		"expires_in": null
+	}`
+	filter = suite.setFilterExpiration(id, nil, nil, &requestJson)
+	suite.Nil(filter.ExpiresAt)
+}
+
+// Regression test related to https://github.com/superseriousbusiness/gotosocial/issues/3497
+func (suite *FiltersTestSuite) TestPutFilterUnalteredExpirationDateJSON() {
+	id := suite.testFilters["local_account_1_filter_4"].ID
+
+	// Setup: set an expiration date for the filter.
+	expiresIn := 86400
+	filter := suite.setFilterExpiration(id, &expiresIn, nil, nil)
+	if !suite.NotNil(filter.ExpiresAt) {
+		suite.FailNow("Test precondition failed")
+	}
+
+	// Update nothing. There should still be an expiration date.
+	requestJson := `{}`
+	filter = suite.setFilterExpiration(id, nil, nil, &requestJson)
+	suite.NotNil(filter.ExpiresAt)
+}

internal/api/model/filterv1.go

@@ -95,5 +95,5 @@ type FilterCreateUpdateRequestV1 struct {
 	// Number of seconds from now that the filter should expire. If omitted, filter never expires.
 	//
 	// Example: 86400
-	ExpiresInI interface{} `json:"expires_in"`
+	ExpiresInI Nullable[any] `json:"expires_in"`
 }

internal/api/model/filterv2.go

@@ -134,7 +134,7 @@ type FilterCreateRequestV2 struct {
 	// Number of seconds from now that the filter should expire. If omitted, filter never expires.
 	//
 	// Example: 86400
-	ExpiresInI interface{} `json:"expires_in"`
+	ExpiresInI Nullable[any] `json:"expires_in"`
 
 	// Keywords to be added to the newly created filter.
 	Keywords []FilterKeywordCreateUpdateRequest `form:"-" json:"keywords_attributes" xml:"keywords_attributes"`
@@ -199,7 +199,7 @@ type FilterUpdateRequestV2 struct {
 	// Number of seconds from now that the filter should expire. If omitted, filter never expires.
 	//
 	// Example: 86400
-	ExpiresInI interface{} `json:"expires_in"`
+	ExpiresInI Nullable[any] `json:"expires_in"`
 
 	// Keywords to be added to the filter, modified, or removed.
 	Keywords []FilterKeywordCreateUpdateDeleteRequest `form:"-" json:"keywords_attributes" xml:"keywords_attributes"`

internal/api/model/nullable.go

@@ -0,0 +1,107 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package model
+
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+)
+
+// Nullable is a generic type, which implements a field that can be one of three states:
+//
+// - field is not set in the request
+// - field is explicitly set to `null` in the request
+// - field is explicitly set to a valid value in the request
+//
+// Nullable is intended to be used with JSON unmarshalling.
+//
+// Adapted from https://github.com/oapi-codegen/nullable/blob/main/nullable.go
+type Nullable[T any] struct {
+	state nullableState
+	value T
+}
+
+type nullableState uint8
+
+const (
+	nullableStateUnspecified nullableState = 0
+	nullableStateNull        nullableState = 1
+	nullableStateSet         nullableState = 2
+)
+
+// Get retrieves the underlying value, if present,
+// and returns an error if the value was not present.
+func (t Nullable[T]) Get() (T, error) {
+	var empty T
+	if t.IsNull() {
+		return empty, errors.New("value is null")
+	}
+
+	if !t.IsSpecified() {
+		return empty, errors.New("value is not specified")
+	}
+
+	return t.value, nil
+}
+
+// IsNull indicates whether the field
+// was sent, and had a value of `null`
+func (t Nullable[T]) IsNull() bool {
+	return t.state == nullableStateNull
+}
+
+// IsSpecified indicates whether the field
+// was sent either as a value or as `null`.
+func (t Nullable[T]) IsSpecified() bool {
+	return t.state != nullableStateUnspecified
+}
+
+// If field is unspecified,
+// UnmarshalJSON won't be called.
+func (t *Nullable[T]) UnmarshalJSON(data []byte) error {
+	// If field is specified as `null`.
+	if bytes.Equal(data, []byte("null")) {
+		t.setNull()
+		return nil
+	}
+
+	// Otherwise, we have an
+	// actual value, so parse it.
+	var v T
+	if err := json.Unmarshal(data, &v); err != nil {
+		return err
+	}
+
+	t.set(v)
+	return nil
+}
+
+// setNull indicates that the field
+// was sent, and had a value of `null`
+func (t *Nullable[T]) setNull() {
+	*t = Nullable[T]{state: nullableStateNull}
+}
+
+// set the underlying value to given value.
+func (t *Nullable[T]) set(value T) {
+	*t = Nullable[T]{
+		state: nullableStateSet,
+		value: value,
+	}
+}

internal/api/util/parseform.go

@@ -20,12 +20,13 @@
 import (
 	"fmt"
 	"strconv"
+
+	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
+	"github.com/superseriousbusiness/gotosocial/internal/util"
 )
 
-// ParseDuration parses the given raw interface belonging to
+// ParseDuration parses the given raw interface belonging
 // the given fieldName as an integer duration.
-//
-// Will return nil, nil if rawI is the zero value of its type.
 func ParseDuration(rawI any, fieldName string) (*int, error) {
 	var (
 		asInteger int
@@ -60,11 +61,28 @@ func ParseDuration(rawI any, fieldName string) (*int, error) {
 		return nil, err
 	}
 
-	// Someone submitted 0,
-	// don't point to this.
-	if asInteger == 0 {
-		return nil, nil
-	}
-
 	return &asInteger, nil
 }
+
+// ParseNullableDuration is like ParseDuration, but
+// for JSON values that may have been sent as `null`.
+//
+// IsSpecified should be checked and "true" on the
+// given nullable before calling this function.
+func ParseNullableDuration(
+	nullable apimodel.Nullable[any],
+	fieldName string,
+) (*int, error) {
+	if nullable.IsNull() {
+		// Was specified as `null`,
+		// return pointer to zero value.
+		return util.Ptr(0), nil
+	}
+
+	rawI, err := nullable.Get()
+	if err != nil {
+		return nil, err
+	}
+
+	return ParseDuration(rawI, fieldName)
+}

internal/processing/filters/v1/create.go

@@ -43,7 +43,7 @@ func (p *Processor) Create(ctx context.Context, account *gtsmodel.Account, form
 	if *form.Irreversible {
 		filter.Action = gtsmodel.FilterActionHide
 	}
-	if form.ExpiresIn != nil {
+	if form.ExpiresIn != nil && *form.ExpiresIn != 0 {
 		filter.ExpiresAt = time.Now().Add(time.Second * time.Duration(*form.ExpiresIn))
 	}
 	for _, context := range form.Context {

internal/processing/filters/v1/update.go

@@ -67,7 +67,7 @@ func (p *Processor) Update(
 		action = gtsmodel.FilterActionHide
 	}
 	expiresAt := time.Time{}
-	if form.ExpiresIn != nil {
+	if form.ExpiresIn != nil && *form.ExpiresIn != 0 {
 		expiresAt = time.Now().Add(time.Second * time.Duration(*form.ExpiresIn))
 	}
 	contextHome := false

internal/processing/filters/v2/create.go

@@ -41,7 +41,7 @@ func (p *Processor) Create(ctx context.Context, account *gtsmodel.Account, form
 		Title:     form.Title,
 		Action:    typeutils.APIFilterActionToFilterAction(*form.FilterAction),
 	}
-	if form.ExpiresIn != nil {
+	if form.ExpiresIn != nil && *form.ExpiresIn != 0 {
 		filter.ExpiresAt = time.Now().Add(time.Second * time.Duration(*form.ExpiresIn))
 	}
 	for _, context := range form.Context {

internal/processing/filters/v2/update.go

@@ -21,8 +21,6 @@
 	"context"
 	"errors"
 	"fmt"
-	"time"
-
 	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
 	"github.com/superseriousbusiness/gotosocial/internal/db"
 	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
@@ -30,6 +28,7 @@
 	"github.com/superseriousbusiness/gotosocial/internal/id"
 	"github.com/superseriousbusiness/gotosocial/internal/typeutils"
 	"github.com/superseriousbusiness/gotosocial/internal/util"
+	"time"
 )
 
 // Update an existing filter for the given account, using the provided parameters.
@@ -68,10 +67,16 @@ func (p *Processor) Update(
 		filterColumns = append(filterColumns, "action")
 		filter.Action = typeutils.APIFilterActionToFilterAction(*form.FilterAction)
 	}
-	// TODO: (Vyr) is it possible to unset a filter expiration with this API?
 	if form.ExpiresIn != nil {
+		expiresIn := *form.ExpiresIn
 		filterColumns = append(filterColumns, "expires_at")
-		filter.ExpiresAt = time.Now().Add(time.Second * time.Duration(*form.ExpiresIn))
+		if expiresIn == 0 {
+			// Unset the expiration date.
+			filter.ExpiresAt = time.Time{}
+		} else {
+			// Update the expiration date.
+			filter.ExpiresAt = time.Now().Add(time.Second * time.Duration(expiresIn))
+		}
 	}
 	if form.Context != nil {
 		filterColumns = append(filterColumns,