Call to a member function getDisplayName() on null [#3206057]

Problem/Motivation

On my website, when I go to the revisions for a node:
https://www.example.org/node/2959/revisions/view/38665/39409/split_fields

We get the following error

Call to a member function getDisplayName() on null
in Drupal\diff\DiffLayoutBase->buildRevisionData()
line 182 of modules/contrib/diff/src/DiffLayoutBase.php

The problem is that $revision->getRevisionUser() is returning null.

This is a probably a case of bad data on my site, but I attach my patch here in case someone finds it useful.

The fix is simply to do a check for null:

$revision_link['author'] = [
  '#type' => 'link',
  '#title' => ($revision_user = $revision->getRevisionUser()) ? $revision_user->getDisplayName() : '',

Comment	File	Size	Author
#11	diff-3206057-11.patch	1.45 KB	martijn de wit
#7	diff-3206057-7.patch	1.47 KB	mingsong
#6	diff-3206057-6.patch	1.52 KB	mingsong
#4	3206057-4.patch	670 bytes	michaellenahan

Issue fork diff-3206057

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changes, plain diff MR !6

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Comments

Comment #1

27 March 2021 at 20:51

michaellenahan created an issue. See original summary.

Comment #2

michaellenahan commented 27 March 2021 at 20:52

Issue summary:

View changes

Comment #3

27 March 2021 at 20:57

michaellenahan opened merge request !6

Comment #4

michaellenahan commented 27 March 2021 at 21:23

Status	File	Size
new	3206057-4.patch	670 bytes

Adding the patch manually here, in addition to the Merge Request.

We're using cweagans/composer-patches in our composer.json - so we will use the url https://www.drupal.org/files/issues/2021-03-27/3206057-4.patch in our composer.json

A method for using gitlab merge requests for patch management is still being worked on here - https://www.drupal.org/project/drupalorg/issues/3204538

Comment #5

michaellenahan commented 27 March 2021 at 21:22

Status:

Active

» Needs review

Comment #6

mingsong

🇦🇺

commented 1 April 2021 at 00:42

Status	File	Size
new	diff-3206057-6.patch	1.52 KB

In the revisions table, the user name for NULL is 'Anonymous (not verified)'. So I suggest using the same name rather than '' for the consistency.

Here is the patch.

I am happy to push it to the PR created for this issue. Just let me know what you think.

Comment #7

mingsong

🇦🇺

commented 1 April 2021 at 00:48

Status	File	Size
new	diff-3206057-7.patch	1.47 KB

1 file was hidden/shown/deleted

Status	File	Size
hidden	diff-3206057-6.patch	1.52 KB

Sorry, patch from #6 was failed from the test.
Here is the new one.

Comment #8

michaellenahan commented 1 April 2021 at 11:26

I am happy to push it to the PR created for this issue. Just let me know what you think.

Yes, that's a good improvement I think.

Comment #9

mingsong

🇦🇺

commented 3 April 2021 at 00:08

Unfortunately, I don't have the access to push code to the repository.

I attach the git diff code here, in case you want to push it back to your repository.

Author: AMDS <AMDS@2986445.no-reply.drupal.org>
Date:   Sat Apr 3 11:02:58 2021 +1100

    Issue #3206057: Call to a member function getDisplayName() on null

diff --git a/src/DiffLayoutBase.php b/src/DiffLayoutBase.php
index e53c32e..b05ca73 100644
--- a/src/DiffLayoutBase.php
+++ b/src/DiffLayoutBase.php
@@ -167,7 +167,17 @@ abstract class DiffLayoutBase extends PluginBase implements DiffLayoutInterface,
   protected function buildRevisionData(ContentEntityInterface $revision) {
     if ($revision instanceof RevisionLogInterface) {
       $revision_log = Xss::filter($revision->getRevisionLogMessage());
+      $revision_user = $revision->getRevisionUser();
       $user_id = $revision->getRevisionUserId();
+      // Get the revision user name.
+      // For historical reason, the revision user might be NULL.
+      // If it is the case, use 'Anonymous' as the user name.
+      if ($revision_user) {
+        $user_name = $revision_user->getDisplayName();
+      }
+      else {
+        $user_name = $this->t('Anonymous (not verified)');
+      }
 
       $revision_link['date'] = [
         '#type' => 'link',
@@ -179,10 +189,10 @@ abstract class DiffLayoutBase extends PluginBase implements DiffLayoutInterface,
 
       $revision_link['author'] = [
         '#type' => 'link',
-        '#title' => ($revision_user = $revision->getRevisionUser()) ? $revision_user->getDisplayName() : '',
+        '#title' => $user_name,
         '#url' => Url::fromUri(\Drupal::request()->getUriForPath('/user/' . $user_id)),
         '#theme' => 'username',
-        '#account' => $revision->getRevisionUser(),
+        '#account' => $revision_user,
         '#prefix' => '<div class="diff-revision__item diff-revision__item-author">',
         '#suffix' => '</div>',
       ];