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Bug #106785

open

PHP Warning: ob_start(): Output handler 'ob_gzhandler' cannot be used twice when creating backend user/group

Added by Sébastien Delcroix 23 days ago. Updated 7 days ago.

Status:
New
Priority:
Should have
Assignee:
-
Category:
System/Bootstrap/Configuration
Target version:
-
Start date:
2025-05-27
Due date:
% Done:

0%

Estimated time:
TYPO3 Version:
12
PHP Version:
Tags:
Complexity:
Is Regression:
Yes
Sprint Focus:

Description

Hi,

since 12.4.31 or 12.4.32, we got this warning when creating backend user or group :

PHP Warning: ob_start(): Output handler 'ob_gzhandler' cannot be used twice in [...]/typo3/sysext/backend/Classes/Middleware/OutputCompression.php line 55

In some dev instances where we enable the Debug preset, this lead to an exception which prevents the user/group creation.

Note : as Garvin asked on Slack, this is not a composer installation

Files

exception_stacktrace_12_4_32_ob_gzhandler.txt (12 KB) exception_stacktrace_12_4_32_ob_gzhandler.txt Stack Trace Sybille Peters, 2025-06-02 08:44
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 #1

Updated by Garvin Hicking 23 days ago

  • Category set to System/Bootstrap/Configuration
  • Is Regression set to Yes
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 #2

Updated by Sébastien Delcroix 23 days ago · Edited

Error happens after clicking on the "verify" button in the modal.

Here is the middlewares sequence :

  1. VerifyHostHeader
  2. NormalizedParamsAttribute
  3. LockedBackendGuard
  4. ForcedHttpsBackendRedirector
  5. ContentSecurityPolicyReporter
  6. BackendRouteInitialization
  7. RequestTokenMiddleware
  8. BackendUserAuthenticator
  9. BackendModuleValidator
  10. OutputCompression
  11. ContentSecurityPolicyHeaders
  12. AdditionalResponseHeaders
  13. SudoModeInterceptor

There is a call to SudoModeInterceptor->handleRequestGrantedException()

this calls typo3_src-12.4.32-dev/typo3/sysext/backend/Classes/Middleware/SudoModeInterceptor.php line 127 :

return $this->application->handle($request);

And then the middlewares sequence starts again until crash :

  1. VerifyHostHeader
  2. NormalizedParamsAttribute
  3. LockedBackendGuard
  4. ForcedHttpsBackendRedirector
  5. ContentSecurityPolicyReporter
  6. BackendRouteInitialization
  7. RequestTokenMiddleware
  8. BackendUserAuthenticator
  9. BackendModuleValidator
  10. OutputCompression
=> #1476107295 TYPO3\CMS\Core\Error\Exception 

PHP Warning: ob_start(): Output handler 'ob_gzhandler' cannot be used twice in [...]/typo3_src-12.4.32-dev/typo3/sysext/backend/Classes/Middleware/OutputCompression.php line 55
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 #3

Updated by Sébastien Delcroix 23 days ago

Weird thing is that I'm in developer context but I have to enter the admin (or Install Tool) password when creating a backend user/group.

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 #6

Updated by Sébastien Delcroix 23 days ago

Hmm OK, I thought that I've read somewhere that this step is bypassed in developer context

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 #7

Updated by Sébastien Delcroix 22 days ago

  • Description updated (diff)
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 #8

Updated by Sybille Peters 17 days ago

Had (probably the same problem:

  • version: 12.4.32
  • Composer installation
  • Development system
  • debug preset

Steps to reproduce:

1. In BE-User module create a new BE user name username "test", fill out name and password
2. Save
3. Now exception is displayed:

#1476107295 TYPO3\CMS\Core\Error\Exception
PHP Warning: ob_start(): Output handler 'ob_gzhandler' cannot be used twice in /var/www/site-uol12/vendor/typo3/cms-backend/Classes/Middleware/OutputCompression.php line 55

Cache was flushed previously.

Stack trace:

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 #9

Updated by Hannes Bochmann 9 days ago

I ran into the same problem when changing the admin flag for BE users.

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 #10

Updated by Michaela Spandl 7 days ago

Same for us in TYPO3 13 and TYPO3 12 - since the last TYPO3 Update (12.4.33) if we change user permissions the password field appears - right after the password confirmation the errors is shown. When I go back to the user permission I can change them. Until next password confirmation. In the last versions I never was able to change user permissions, so now it is a little bit better but still the error first.

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