[SOLVED] Error after J3.6.4 update: Error decoding JSON data: unexpected end of data

Hi, after update to J3.6.4, i get in administrator when trying to access content items :
Error decoding JSON data: unexpected end of data
I tried to update to FC3.1.0.
No change...

Browser cache and site cache cleared without any change...
Any clue ?
Thanks
Xavier

Ok.
If i try to access to all content in the admin, i get the error.
I i acces the categories and then click on the number showing the number of items, i can have the list, modifying, etc..
But if i removed all the filter, i have then the error.
???

Hello

- J3.6.4 has changed the code and when a bad JSON string is encountered, and it will throw an exception
(and if extension does not catch the exception, the page breaks)

There is long discussion about it in Joomla issue tracker:
github.com/joomla/joomla-cms/issues/12460

To get more info e.g. for Joomla backend if using ISIS Template:
edit file:
administrator/templates/isis/error.php

Find:

and after it add:
This way we can know where the error has occured

Hello

actually you only need to enable "DEBUG" in Joomla global configuration

and then visit the page that should tell us where the error is thrown
- copy paste here the "Trace" that will be printed

Hi Georges,
First, after modifying isis error page, i get with the debug (replace my site name by "mysite" :

0 Error decoding JSON data: unexpected end of data
72 /var/www/vhosts/mysite.com/httpdocs/libraries/vendor/joomla/registry/src/Format/Json.php

Call stack
# Function Location
1 JApplicationCms->execute() /var/www/vhosts/mysite.com/httpdocs/administrator/index.php:51
2 JApplicationAdministrator->doExecute() /var/www/vhosts/mysite.com/httpdocs/libraries/cms/application/cms.php:261
3 JApplicationAdministrator->dispatch() /var/www/vhosts/mysite.com/httpdocs/libraries/cms/application/administrator.php:152
4 JComponentHelper::renderComponent() /var/www/vhosts/mysite.com/httpdocs/libraries/cms/application/administrator.php:98
5 JComponentHelper::executeComponent() /var/www/vhosts/mysite.com/httpdocs/libraries/cms/component/helper.php:380
6 require_once() /var/www/vhosts/mysite.com/httpdocs/libraries/cms/component/helper.php:405
7 require_once() /var/www/vhosts/mysite.com/httpdocs/administrator/components/com_flexicontent/flexicontent.php:22
8 JControllerLegacy->execute() /var/www/vhosts/mysite.com/httpdocs/administrator/components/com_flexicontent/admin.flexicontent.php:291
9 FlexicontentController->display() /var/www/vhosts/mysite.com/httpdocs/libraries/legacy/controller/legacy.php:702
10 JControllerLegacy->display() /var/www/vhosts/mysite.com/httpdocs/administrator/components/com_flexicontent/controller.php:323
11 FlexicontentViewItems->display() /var/www/vhosts/mysite.com/httpdocs/libraries/legacy/controller/legacy.php:664
12 JViewLegacy->get() /var/www/vhosts/mysite.com/httpdocs/administrator/components/com_flexicontent/views/items/view.html.php:362
13 FlexicontentModelItems->getData() /var/www/vhosts/mysite.com/httpdocs/libraries/legacy/view/legacy.php:408
14 Joomla\Registry\Registry->__construct() /var/www/vhosts/mysite.com/httpdocs/administrator/components/com_flexicontent/models/items.php:369
15 Joomla\Registry\Registry->loadString() /var/www/vhosts/mysite.com/httpdocs/libraries/vendor/joomla/registry/src/Registry.php:72
16 Joomla\Registry\Format\Json->stringToObject() /var/www/vhosts/mysite.com/httpdocs/libraries/vendor/joomla/registry/src/Registry.php:366

After reading the post you gave me, i have tried "update xxxx_modules set params="" WHERE params = "{\"\"}";" without any results..

Can give me a hand on this ?
I check other sites : no issues of this type on FC items in backend.
Only one site have the issue. The strange thing : that's not a migrated site from J1 or j2, just an update from 3.6.2 to 3.6.4...
Thanks Georges,
Xavier

Hello

the trace that you posted tell us exactly where the error is

actually the fix is simple in case of bad data we need to catch the exception thrown by

new JRegistry(...);

and prevent the fatal error,

- also proper thing is to automate fixing this, if we detect bad JSON data then we clear the data from DB so that user does not need to do it manually

i will give you shortly or later today (because i also want to write a few lines of code to automate fix it in the DB),

and then of course will add the fix to our next release, so that the check benefits other users too

Georges, i'm not a "full beginner" but in this case, you are so far in the sky amongst me
You write "the trace tell you exactly where is the error".
Well i'm sure you see it but i don't get the full knowledge to see what you see in debug
I don't know yet how to handle this message and resolve it.
I wait hungerly for your script and, if and only if you have the time for, the explanation on how to read and resolve this kind of issue in general with the debug info
Thanks to you Georges
Xavier

Hello

edit file: (at line 369)
administrator/components/com_flexicontent/models/items.php:

Replace line:
with:
Then view the backend items manager page 2 times

- note there are more places to add checks

e.g. if you try to view the item with the broken JSON attributes in the frontend then you will get an error

but if you list it in the backend items manager then it will be fixed (thanks to above fix) then it will be fixed and you can then view it in frontend


- I will manually break the attributes of an item to see where the error is triggered to add check to all needed places ...

all these will be in v3.1.1 (coming this weekend) (v3.1.1 will only have a handful of fixes for rare issues and no new features)

Hi Georges,
Uh.... in the file item.php i only have 44 lines...