3 files changed, 50 insertions, 7 deletions
diff --git a/internal/api/client/accounts/accountcreate.go b/internal/api/client/accounts/accountcreate.go
index c8247ecf2..473000f6d 100644
--- a/internal/api/client/accounts/accountcreate.go
+++ b/internal/api/client/accounts/accountcreate.go
@@ -87,7 +87,7 @@ func (m *Module) AccountCreatePOSTHandler(c *gin.Context) {
 		return
 	}
 
-	if err := validateCreateAccount(form); err != nil {
+	if err := validateNormalizeCreateAccount(form); err != nil {
 		apiutil.ErrorHandler(c, gtserror.NewErrorBadRequest(err, err.Error()), m.processor.InstanceGetV1)
 		return
 	}
@@ -110,9 +110,10 @@ func (m *Module) AccountCreatePOSTHandler(c *gin.Context) {
 	c.JSON(http.StatusOK, ti)
 }
 
-// validateCreateAccount checks through all the necessary prerequisites for creating a new account,
+// validateNormalizeCreateAccount checks through all the necessary prerequisites for creating a new account,
 // according to the provided account create request. If the account isn't eligible, an error will be returned.
-func validateCreateAccount(form *apimodel.AccountCreateRequest) error {
+// Side effect: normalizes the provided language tag for the user's locale.
+func validateNormalizeCreateAccount(form *apimodel.AccountCreateRequest) error {
 	if form == nil {
 		return errors.New("form was nil")
 	}
@@ -137,9 +138,11 @@ func validateCreateAccount(form *apimodel.AccountCreateRequest) error {
 		return errors.New("agreement to terms and conditions not given")
 	}
 
-	if err := validate.Language(form.Locale); err != nil {
+	locale, err := validate.Language(form.Locale)
+	if err != nil {
 		return err
 	}
+	form.Locale = locale
 
 	return validate.SignUpReason(form.Reason, config.GetAccountsReasonRequired())
 }
diff --git a/internal/api/client/statuses/statuscreate.go b/internal/api/client/statuses/statuscreate.go
index e4d8588c7..e8378f461 100644
--- a/internal/api/client/statuses/statuscreate.go
+++ b/internal/api/client/statuses/statuscreate.go
@@ -98,7 +98,7 @@ func (m *Module) StatusCreatePOSTHandler(c *gin.Context) {
 	// }
 	// form.Status += "\n\nsent from " + user + "'s iphone\n"
 
-	if err := validateCreateStatus(form); err != nil {
+	if err := validateNormalizeCreateStatus(form); err != nil {
 		apiutil.ErrorHandler(c, gtserror.NewErrorBadRequest(err, err.Error()), m.processor.InstanceGetV1)
 		return
 	}
@@ -112,7 +112,9 @@ func (m *Module) StatusCreatePOSTHandler(c *gin.Context) {
 	c.JSON(http.StatusOK, apiStatus)
 }
 
-func validateCreateStatus(form *apimodel.AdvancedStatusCreateForm) error {
+// validateNormalizeCreateStatus checks the form for disallowed combinations of attachments and overlength inputs.
+// Side effect: normalizes the post's language tag.
+func validateNormalizeCreateStatus(form *apimodel.AdvancedStatusCreateForm) error {
 	hasStatus := form.Status != ""
 	hasMedia := len(form.MediaIDs) != 0
 	hasPoll := form.Poll != nil
@@ -162,9 +164,11 @@ func validateCreateStatus(form *apimodel.AdvancedStatusCreateForm) error {
 	}
 
 	if form.Language != "" {
-		if err := validate.Language(form.Language); err != nil {
+		language, err := validate.Language(form.Language)
+		if err != nil {
 			return err
 		}
+		form.Language = language
 	}
 
 	return nil
diff --git a/internal/api/client/statuses/statuscreate_test.go b/internal/api/client/statuses/statuscreate_test.go
index 05f24c24c..d47a74bbc 100644
--- a/internal/api/client/statuses/statuscreate_test.go
+++ b/internal/api/client/statuses/statuscreate_test.go
@@ -391,6 +391,42 @@ func (suite *StatusCreateTestSuite) TestAttachNewMediaSuccess() {
 	suite.Equal(statusResponse.ID, gtsAttachment.StatusID)
 }
 
+// Post a new status with a language tag that is not in canonical format
+func (suite *StatusCreateTestSuite) TestPostNewStatusWithNoncanonicalLanguageTag() {
+	t := suite.testTokens["local_account_1"]
+	oauthToken := oauth.DBTokenToToken(t)
+
+	// setup
+	recorder := httptest.NewRecorder()
+	ctx, _ := testrig.CreateGinTestContext(recorder, nil)
+	ctx.Set(oauth.SessionAuthorizedApplication, suite.testApplications["application_1"])
+	ctx.Set(oauth.SessionAuthorizedToken, oauthToken)
+	ctx.Set(oauth.SessionAuthorizedUser, suite.testUsers["local_account_1"])
+	ctx.Set(oauth.SessionAuthorizedAccount, suite.testAccounts["local_account_1"])
+	ctx.Request = httptest.NewRequest(http.MethodPost, fmt.Sprintf("http://localhost:8080/%s", statuses.BasePath), nil) // the endpoint we're hitting
+	ctx.Request.Header.Set("accept", "application/json")
+	ctx.Request.Form = url.Values{
+		"status":   {"English? what's English? i speak American"},
+		"language": {"en-us"},
+	}
+	suite.statusModule.StatusCreatePOSTHandler(ctx)
+
+	suite.EqualValues(http.StatusOK, recorder.Code)
+
+	result := recorder.Result()
+	defer result.Body.Close()
+	b, err := ioutil.ReadAll(result.Body)
+	suite.NoError(err)
+
+	statusReply := &apimodel.Status{}
+	err = json.Unmarshal(b, statusReply)
+	suite.NoError(err)
+
+	suite.Equal("<p>English? what's English? i speak American</p>", statusReply.Content)
+	suite.NotNil(statusReply.Language)
+	suite.Equal("en-US", *statusReply.Language)
+}
+
 func TestStatusCreateTestSuite(t *testing.T) {
 	suite.Run(t, new(StatusCreateTestSuite))
 }