Fix linking to invariable image URLs

[ahukkanen]

🎩 What? Why?

Not all environments support creating "variable URLs" for all image types. Let's say the admin user would allow uploading image files that cannot be converted using ImageMagick.

In this case, the file conversion fails because of an exception of type ActiveStorage::InvariableError is thrown.

How the user would see this is that they cannot e.g. preview their proposal or see the proposal page because it is trying to create the thumbnail URLs for these images. This PR fixes the issue by falling back to the original URL of that file.

📌 Related Issues

• Fixes Invariable attachments cause the proposal page to break #10237

Testing

• Within the development_app's config/environments/development.rb, add the following configuration: config.active_storage.variable_content_types = %w(image/png)
• Make sure image/jpeg is allowed from the Decidim system panel (it should be if you haven't changed anything)
• Allow attachments for proposals
• Try to submit a proposal with a JPEG image or attachment
• See error (before this patch)

[alecslupu]

@ahukkanen I do not have enough informations for testing scenario.
I have addded ActiveStorage.variable_content_types = %w(image/png) to decidim initializer, tried to move it to application.rb, yet in both cases, the image ( jpeg files ) were uploaded.

All the changes ere tested for replication on develop brach, using ruby 3.1.2

[alecslupu]

I have tried with the following image magick versions:

Setting up imagemagick (8:6.9.11.60+dfsg-1.3+deb11u1) ...
Setting up imagemagick-6.q16 (8:6.9.11.60+dfsg-1.3+deb11u1) ...

root@58cdd7681fae:/code# identify --version
Version: ImageMagick 6.9.11-60 Q16 x86_64 2021-01-25 https://imagemagick.org
Copyright: (C) 1999-2021 ImageMagick Studio LLC
License: https://imagemagick.org/script/license.php
Features: Cipher DPC Modules OpenMP(4.5) 
Delegates (built-in): bzlib djvu fftw fontconfig freetype heic jbig jng jp2 jpeg lcms lqr ltdl lzma openexr pangocairo png tiff webp wmf x xml zlib

[alecslupu]

i have upgraded to

Version: ImageMagick 7.1.0-4 Q16 x86_64 2021-07-18 https://imagemagick.org
Copyright: (C) 1999-2021 ImageMagick Studio LLC
License: https://imagemagick.org/script/license.php
Features: Cipher DPC HDRI Modules OpenMP(4.5) 
Delegates (built-in): bzlib djvu fontconfig freetype gslib heic jbig jng jp2 jpeg lcms lqr ltdl lzma openexr pangocairo png ps raqm raw tiff webp wmf x xml zip zlib

Yet, i could not replicate the bug.
My system admin panel looks like:

[ahukkanen]

@alecslupu Sorry, I have mistakenly written the configuration instructions for this. I have just corrected it. You need to set the variable_content_types configuration through the environment configuration file, not through an initializer.

Rails will actually override the initializer configuration with the value set in the environment configuration.

Here is a screencap how I can replicate this issue at develop:

decidim-invariable-error.mp4

And when running under this branch I don't get that error anymore.

[alecslupu]

I still could not replicate the upload problem, yet, i could see the ActiveStorage::InvariableError on the homepage using latest develop branch. It dissapeared one the patch was applied.

[sdelcroix]

Any chance to see this backported to v0.26 ? :)