Fix file_get_content signatures to make it clear it can return false

[come-nc]

Summary

In File::getContent, which must return a string, throw an Exception instead of returning false.

This avoids some TypeError that I’ve seen reported recently, either through SimpleFile which has a strong return type, or through a call to getimagesizefromstring which expects a string.

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)

[DaphneMuller]

Hello!
Thank you for your work on this! I noticed that your PR still has the label 'documentation'. I'm not sure if you already had a look at the documentation for your PR, but at Nextcloud we strive to document changes that affect other app developers or other admins before the release takes place, and I'm pinging you with the hope to get this done.

Are you familiar with our documentation process already?
Changes that affect app developers should be documented here:
https://docs.nextcloud.com/server/27/developer_manual/app_publishing_maintenance/app_upgrade_guide/upgrade_to_27.html

Changes that affect administrators should be documented here:
https://docs.nextcloud.com/server/latest/admin_manual/release_notes/upgrade_to_27.html

While I understand sometimes it's handy to merge fast to get your changes in, it would be great if next time you could try to add the documentation before merging. You can find more information on that here:
https://docs.nextcloud.com/server/27/developer_manual/prologue/compatibility_app_ecosystem.html#documentation-procedures-of-changes-that-affect-app-developers

If all your documentation efforts are done, please remove the label 'documentation' and check the checkbox in your opening note and I'll stop bugging you :)

Many thanks in advance and thanks again for your work!

[digidax]

Problem still present in 26.0.3rc2

https://help.nextcloud.com/t/webdav-with-folder-sync-typeerror-getimagesizefromstring-internal-server-error/164529

[come-nc]

Problem still present in 26.0.3rc2

https://help.nextcloud.com/t/webdav-with-folder-sync-typeerror-getimagesizefromstring-internal-server-error/164529

This PR was not backported to 26.
Not sure it is a good idea to backport this as it touches types in OCP, even if only phpdoc.

[digidax]

Have applied as workaround (until v27 is available) this patch from master and it's working now.

https://github.com/nextcloud/server/commit/997efe44ffd56959f198be2e3aa71687a2f11412

[MWL1701]

Hello, I made an update to 27.0.2 yesterday and since then I have the GenericFileException error. Unfortunately I do not know what to do. Can someone help me with this?
Here is my error-stack:
[core] Fehler: OCP\Files\GenericFileException: at <>

0. /var/www/nextcloud/lib/private/Files/SimpleFS/SimpleFile.php line 74
   OC\Files\Node\File->getContent()
1. /var/www/nextcloud/lib/private/Template/JSCombiner.php line 118
   OC\Files\SimpleFS\SimpleFile->getContent()
2. /var/www/nextcloud/lib/private/Template/JSCombiner.php line 93
   OC\Template\JSCombiner->isCached()
3. /var/www/nextcloud/lib/private/Template/JSResourceLocator.php line 145
   OC\Template\JSCombiner->process()
4. /var/www/nextcloud/lib/private/Template/JSResourceLocator.php line 103
   OC\Template\JSResourceLocator->cacheAndAppendCombineJsonIfExist()
5. /var/www/nextcloud/lib/private/Template/ResourceLocator.php line 73
   OC\Template\JSResourceLocator->doFind()
6. /var/www/nextcloud/lib/private/TemplateLayout.php line 377
   OC\Template\ResourceLocator->find()
7. /var/www/nextcloud/lib/private/TemplateLayout.php line 222
   OC\TemplateLayout::findJavascriptFiles()
8. /var/www/nextcloud/lib/private/legacy/OC_Template.php line 182
   OC\TemplateLayout->__construct()
9. /var/www/nextcloud/lib/private/Template/Base.php line 132
   OC_Template->fetchPage()
10. /var/www/nextcloud/lib/private/legacy/OC_Template.php line 331
    OC\Template\Base->printPage()
11. /var/www/nextcloud/index.php line 74
    OC_Template::printExceptionErrorPage()

GET /index.php/apps/files/
from by at 2023-08-16T06:37:02+00:00

[MWL1701]

Found the solution:
In the config.php there was a new entry "update-secret", which had to be removed. Then it worked again.

[gjanssens]

My nextcloud setup is tracking the stable branch and currently only offers 25.0.13 as most recent version. Any chance this fix will be backported to that version ? For now I have manually applied part of the patch to lib/private/Files/Node/File.php and that seems to work, but I hope I don't have to continue applying these until the stable channel offers me an upgrade to 27.0.x.

[come-nc]

My nextcloud setup is tracking the stable branch and currently only offers 25.0.13 as most recent version. Any chance this fix will be backported to that version ? For now I have manually applied part of the patch to lib/private/Files/Node/File.php and that seems to work, but I hope I don't have to continue applying these until the stable channel offers me an upgrade to 27.0.x.

Are you on PHP 7.4 by any chance? That may explain why the update to 26 is not offered to you, you need to update PHP to a supported version first I think.

[gjanssens]

I'm indeed still on PHP7.4. I had seen the warnings in the admin panel but didn't realize those were actually preventing further upgrades. Thanks for pointing that out, I'll go and upgrade PHP first.

[gjanssens]

I'm indeed still on PHP7.4. I had seen the warnings in the admin panel but didn't realize those were actually preventing further upgrades. Thanks for pointing that out, I'll go and upgrade PHP first.

In case anyone else gets here with the same question I had, upgrading PHP did indeed result in nextcloud offering upgrades to newer releases again. Thanks @come-nc for the pointer.