Addressing some PHP8 incompatibilities - Diffusion & Differential

Summary: Running through setting up and using Diffusion repositories and addressing PHP8 issues that come up.

Test Plan:
I set up a hosted mercurial repository and pushed commits to it over ssh.
I set up a hosted git repository and pushed commits to it over ssh.
I set up a mirrored mercurial repository over ssh.
I set up a mirrored git repository over ssh.

I created a diff on a git repository and landed it.
I created a diff on a mercurial repository and landed it.

I cloned and pushed a commit to a mercurial repo over http.
I cloned and pushed a commit to a git repo over http.

Reviewers: #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

Subscribers: Korvin, epriestley

Differential Revision: https://secure.phabricator.com/D21864

Author: neandrake

scripts/ssh/ssh-auth.php

@@ -36,7 +36,7 @@
 
 $authstruct = null;
 
-if (strlen($authstruct_raw)) {
+if ($authstruct_raw !== null && strlen($authstruct_raw)) {
   try {
     $authstruct = phutil_json_decode($authstruct_raw);
   } catch (Exception $ex) {
@@ -135,7 +135,7 @@
 
   $cmd = csprintf('%s %Ls', $bin, $key_argv);
 
-  if (strlen($instance)) {
+  if ($instance !== null && strlen($instance)) {
     $cmd = csprintf('PHABRICATOR_INSTANCE=%s %C', $instance, $cmd);
   }
 

src/applications/almanac/util/AlmanacKeys.php

@@ -58,7 +58,7 @@ public static function getLiveDevice() {
 
   public static function getClusterSSHUser() {
     $username = PhabricatorEnv::getEnvConfig('diffusion.ssh-user');
-    if (strlen($username)) {
+    if ($username !== null && strlen($username)) {
       return $username;
     }
 

src/applications/conduit/query/PhabricatorConduitSearchEngine.php

@@ -39,7 +39,7 @@ public function buildQueryFromSavedQuery(PhabricatorSavedQuery $saved) {
     $query->withIsInternal(false);
 
     $contains = $saved->getParameter('nameContains');
-    if (strlen($contains)) {
+    if ($contains !== null && strlen($contains)) {
       $query->withNameContains($contains);
     }
 

src/applications/config/controller/module/PhabricatorConfigModuleController.php

@@ -9,7 +9,7 @@ public function handleRequest(AphrontRequest $request) {
 
     $all_modules = PhabricatorConfigModule::getAllModules();
 
-    if (!strlen($key)) {
+    if ($key === null || !strlen($key)) {
       $key = head_key($all_modules);
     }
 

src/applications/differential/conduit/DifferentialGetCommitMessageConduitAPIMethod.php

@@ -56,7 +56,7 @@ protected function execute(ConduitAPIRequest $request) {
     // show "Field:" templates for some fields even if they are empty.
     $edit_mode = $request->getValue('edit');
 
-    $is_any_edit = (bool)strlen($edit_mode);
+    $is_any_edit = $edit_mode !== null && (bool)strlen($edit_mode);
     $is_create = ($edit_mode == 'create');
 
     $field_list = DifferentialCommitMessageField::newEnabledFields($viewer);
@@ -115,7 +115,7 @@ protected function execute(ConduitAPIRequest $request) {
 
       $is_title = ($field_key == $key_title);
 
-      if (!strlen($value)) {
+      if ($value === null || !strlen($value)) {
         if ($is_template) {
           $commit_message[] = $label.': ';
         }

src/applications/differential/customfield/DifferentialBranchField.php

@@ -39,13 +39,20 @@ private function getBranchDescription(DifferentialDiff $diff) {
     $branch = $diff->getBranch();
     $bookmark = $diff->getBookmark();
 
+    if ($branch === null) {
+      $branch = '';
+    }
+    if ($bookmark === null) {
+      $bookmark = '';
+    }
+
     if (strlen($branch) && strlen($bookmark)) {
       return pht('%s (bookmark) on %s (branch)', $bookmark, $branch);
     } else if (strlen($bookmark)) {
       return pht('%s (bookmark)', $bookmark);
     } else if (strlen($branch)) {
       $onto = $diff->loadTargetBranch();
-      if (strlen($onto) && ($onto !== $branch)) {
+      if ($onto !== null && strlen($onto) && ($onto !== $branch)) {
         return pht(
           '%s (branched from %s)',
           $branch,

src/applications/differential/field/DifferentialCommitMessageField.php

@@ -60,7 +60,7 @@ public function readFieldValueFromObject(DifferentialRevision $revision) {
   }
 
   public function renderFieldValue($value) {
-    if (!strlen($value)) {
+    if ($value === null || !strlen($value)) {
       return null;
     }
 

src/applications/differential/field/DifferentialRevisionIDCommitMessageField.php

@@ -72,7 +72,7 @@ public function readFieldValueFromConduit($value) {
   }
 
   public function renderFieldValue($value) {
-    if (!strlen($value)) {
+    if ($value === null || !strlen($value)) {
       return null;
     }
 

src/applications/differential/storage/DifferentialChangeset.php

@@ -325,7 +325,7 @@ public function getDiff() {
 
   public function getOldStatePathVector() {
     $path = $this->getOldFile();
-    if (!strlen($path)) {
+    if ($path === null || !strlen($path)) {
       $path = $this->getFilename();
     }
 

src/applications/differential/view/DifferentialRevisionUpdateHistoryView.php

@@ -251,6 +251,7 @@ public function render() {
     $content = phabricator_form(
       $this->getUser(),
       array(
+        'method' => 'GET',
         'action' => '/D'.$revision_id.'#toc',
       ),
       array(