To reproduce this issue, visit this page:
```
/auth/config/edit/?provider=PhabricatorPhabricatorAuthProvider
```
Stack trace:
```
[Fri May 19 14:23:35.506028 2023] [php7:notice] [pid 20439] [client 127.0.0.1:39692] [2023-05-19 14:23:35] EXCEPTION: (InvalidArgumentException) Call to phutil_nonempty_string() expected null or a string, got: PhutilSafeHTML. at [<arcanist>/src/utils/utils.php:2127]
[Fri May 19 14:23:35.506647 2023] [php7:notice] [pid 20439] [client 127.0.0.1:39692] arcanist(head=arcpatch-D25049, ref.master=c14785c3795c, ref.arcpatch-D25049=1b6412c24640), phorge(head=arcpatch-D25216_1, ref.master=2df7ea13a387, ref.arcpatch-D25216_1=02b40a9e25eb)
[Fri May 19 14:23:35.506661 2023] [php7:notice] [pid 20439] [client 127.0.0.1:39692] #0 <#2> phutil_nonempty_string(PhutilSafeHTML) called at [<phorge>/src/view/form/control/AphrontFormControl.php:206]
[Fri May 19 14:23:35.506665 2023] [php7:notice] [pid 20439] [client 127.0.0.1:39692] #1 <#2> phutil_tag(string, array, array) called at [<phorge>/src/view/form/PHUIFormLayoutView.php:54]
[Fri May 19 14:23:35.506667 2023] [php7:notice] [pid 20439] [client 127.0.0.1:39692] #2 <#2> PHUIFormLayoutView::render() called at [<phorge>/src/view/form/AphrontFormView.php:160]
[Fri May 19 14:23:35.506670 2023] [php7:notice] [pid 20439] [client 127.0.0.1:39692] #3 <#2> phutil_tag(string, array, array) called at [<phorge>/src/infrastructure/javelin/markup.php:70]
[Fri May 19 14:23:35.506672 2023] [php7:notice] [pid 20439] [client 127.0.0.1:39692] #4 <#2> phutil_escape_html(array) called at [<phorge>/src/infrastructure/markup/render.php:139]
[Fri May 19 14:23:35.506675 2023] [php7:notice] [pid 20439] [client 127.0.0.1:39692] #5 <#2> phutil_escape_html(array) called at [<phorge>/src/infrastructure/markup/render.php:97]
[Fri May 19 14:23:35.506678 2023] [php7:notice] [pid 20439] [client 127.0.0.1:39692] #6 <#2> phutil_tag(string, array, array) called at [<phorge>/src/view/phui/PHUITwoColumnView.php:242]
[Fri May 19 14:23:35.506680 2023] [php7:notice] [pid 20439] [client 127.0.0.1:39692] #7 <#2> PHUITwoColumnView::buildFooter() called at [<phorge>/src/view/phui/PHUITwoColumnView.php:123]
[Fri May 19 14:23:35.506683 2023] [php7:notice] [pid 20439] [client 127.0.0.1:39692] #8 <#2> PHUITwoColumnView::getTagContent() called at [<phorge>/src/view/AphrontTagView.php:161]
[Fri May 19 14:23:35.506685 2023] [php7:notice] [pid 20439] [client 127.0.0.1:39692] #9 <#2> AphrontTagView::render() called at [<phorge>/src/view/AphrontView.php:222]
[Fri May 19 14:23:35.506688 2023] [php7:notice] [pid 20439] [client 127.0.0.1:39692] #10 <#2> AphrontView::producePhutilSafeHTML() called at [<phorge>/src/infrastructure/markup/render.php:115]
[Fri May 19 14:23:35.506691 2023] [php7:notice] [pid 20439] [client 127.0.0.1:39692] #11 <#2> phutil_escape_html(PHUITwoColumnView) called at [<phorge>/src/infrastructure/markup/render.php:171]
[Fri May 19 14:23:35.506693 2023] [php7:notice] [pid 20439] [client 127.0.0.1:39692] #12 <#2> phutil_implode_html(string, array) called at [<phorge>/src/view/page/PhabricatorBarePageView.php:58]
[Fri May 19 14:23:35.506696 2023] [php7:notice] [pid 20439] [client 127.0.0.1:39692] #13 <#2> PhabricatorBarePageView::willRenderPage() called at [<phorge>/src/view/page/PhabricatorStandardPageView.php:216]
[Fri May 19 14:23:35.506699 2023] [php7:notice] [pid 20439] [client 127.0.0.1:39692] #14 <#2> PhabricatorStandardPageView::willRenderPage() called at [<phorge>/src/view/page/AphrontPageView.php:46]
[Fri May 19 14:23:35.506701 2023] [php7:notice] [pid 20439] [client 127.0.0.1:39692] #15 <#2> AphrontPageView::render() called at [<phorge>/src/view/page/PhabricatorStandardPageView.php:904]
[Fri May 19 14:23:35.506704 2023] [php7:notice] [pid 20439] [client 127.0.0.1:39692] #16 <#2> PhabricatorStandardPageView::produceAphrontResponse() called at [<phorge>/src/aphront/configuration/AphrontApplicationConfiguration.php:722]
[Fri May 19 14:23:35.506707 2023] [php7:notice] [pid 20439] [client 127.0.0.1:39692] #17 <#2> AphrontApplicationConfiguration::produceResponse(AphrontRequest, PhabricatorStandardPageView) called at [<phorge>/src/aphront/configuration/AphrontApplicationConfiguration.php:299]
[Fri May 19 14:23:35.506709 2023] [php7:notice] [pid 20439] [client 127.0.0.1:39692] #18 phlog(InvalidArgumentException) called at [<phorge>/src/aphront/handler/PhabricatorDefaultRequestExceptionHandler.php:41]
[Fri May 19 14:23:35.506712 2023] [php7:notice] [pid 20439] [client 127.0.0.1:39692] #19 PhabricatorDefaultRequestExceptionHandler::handleRequestThrowable(AphrontRequest, InvalidArgumentException) called at [<phorge>/src/aphront/configuration/AphrontApplicationConfiguration.php:751]
[Fri May 19 14:23:35.506717 2023] [php7:notice] [pid 20439] [client 127.0.0.1:39692] #20 AphrontApplicationConfiguration::handleThrowable(InvalidArgumentException) called at [<phorge>/src/aphront/configuration/AphrontApplicationConfiguration.php:337]
[Fri May 19 14:23:35.506720 2023] [php7:notice] [pid 20439] [client 127.0.0.1:39692] #21 AphrontApplicationConfiguration::processRequest(AphrontRequest, PhutilDeferredLog, AphrontPHPHTTPSink, MultimeterControl) called at [<phorge>/src/aphront/configuration/AphrontApplicationConfiguration.php:204]
[Fri May 19 14:23:35.506723 2023] [php7:notice] [pid 20439] [client 127.0.0.1:39692] #22 AphrontApplicationConfiguration::runHTTPRequest(AphrontPHPHTTPSink) called at [<phorge>/webroot/index.php:35]
```
The problem was caused by the following line, since apparently the caption can also be not just a string:
```
if (phutil_nonempty_string($this->getCaption())) {
```