Problem

  • When an exception is thrown during a entity storage controller save() operation, all you get is this fatal error:
    Error message

Exception: Serialization of 'Closure' is not allowed in serialize() (line 154 of \core\modules\dblog\dblog.module).

The website has encountered an error. Please try again later.
  • Whereas the dumping the entry that was supposed to be logged contains the actual error that may be this:
    SQLSTATE[42S22]: Column not found: 1054 Unknown column ...

Cause

  • The $log_entry being passed to hook_watchdog() contains a 'backtrace' in its variables, which in turn contains the DrupalKernel/DI container and other classes and Closures that cannot be serialized.
  • dblog_watchdog() performs this:
          'variables' => serialize($log_entry['variables']),
CommentFileSizeAuthor
#1 watchdog.backtrace.1.patch596 bytessun

Comments

sun’s picture

sun
Primary language German
Location Karlsruhe
commented
Status: Active » Needs review
StatusFileSize
new watchdog.backtrace.1.patch596 bytes

Attached patch at least shows the actual error message.

However, we might want to revisit whether it is a good idea to put the backtrace into those variables in the first place...?

We could add it to $log_entry itself instead of 'variables'? Or do you want to record the backtrace in the log message?

If so, we'd have to find a way to serialize a backtrace that contains objects that cannot be serialized.

That said, I'd bet that you actually want to log the string representation of the backtrace only?

das-peter’s picture

das-peter commented

Related: #1872690: Exception: Serialization of 'Closure' is not allowed in serialize

olli’s picture

olli commented

I'd bet that you actually want to log the string representation of the backtrace only?

Do you mean something like:

-    'backtrace' => $backtrace,
+    '!backtrace' => format_backtrace($backtrace),

already in _drupal_decode_exception() instead of killing the backtrace everywhere?

tim.plunkett’s picture

tim.plunkett
he/him
Primary language English
Location Philadelphia
commented
Status: Needs review » Reviewed & tested by the community
Issue tags: +Quick fix

That doesn't actually work, you get "Undefined index 'args'" in format_backtrace(). This is fine as is, and is holding up patches like #1952842: Views UI still uses NOT_USED for page callbacks

webchick’s picture

webchick
she/they
Primary language English
Location Vancouver 🇨🇦
commented
Status: Reviewed & tested by the community » Fixed

I couldn't quite parse that comment, but Tim and I went back and forth a bit and came up with:

// Remove any backtraces since they may contain an unserializable variable.

If that's not quite correct we can adjust it in a follow-up, but in the meantime this would unblock #1952842: Views UI still uses NOT_USED for page callbacks which is quite a silly problem to have.

Committed and pushed to 8.x. Thanks!

yched’s picture

yched commented

Couldn't we rework format_backtrace() so that it only contains the function names in the callstack, without the arguments ?

olli’s picture

olli commented

@tim.plunkett: you are right. That is getting fixed in #1832300: Followup: Add backtrace to all errors - Notice undefined index 'args'.

Automatically closed -- issue fixed for 2 weeks with no activity.